Silkscreening Modular Synth Panels

DIY modular synthesis has become very popular as more and more vendors offer printed circuit boards (PCBs) which can be populated to become synthesizer modules.  Some of these PCBs even come in kit form which includes the board, component parts and a panel. Many, however, come as a standalone board leaving it up to the end user to obtain the rest of the items required to complete the module.  This option is (arguably) the most cost effective method as it gives the builder the choice of component vendors and purchase quantities.  If you are planning on building several modules buying electronic components in bulk a very good way to keep your modules cost down.

Panels, however, are a different story.  Mention panels to many modular builders and they’ll cringe.  Often times, at least for me, obtaining a panel to house your electronics is the hold-up point for the project.  Many fine vendors out there sell finished panels which include the graphics for the potentiometers, jacks, switches, lights, etc… along with the pre-drilled holes to mount your parts into.  This is a great option for builders and while it does add some expense to the project, the convenience of being able to order the panel and then finish the build is worth the cost.

Sometimes, though, with the addition of shipping expenses, taxes and currency conversions a panel which is priced very reasonably by the vendor can end up costing more than the electronics portion of the module itself.

I have gone through a number of options for obtaining panels for my builds;  I’ve purchased panels from vendors who produce them for sale.  I’ve had them screened by a local printing company and I’ve produced them myself through the process of silkscreening.  For me the first two options have been very cost prohibitive.  If building one-off versions of the modules for myself this is sometimes a viable option but if building the modules for sale to others it drives the construction price right out of the market.  Ultimately I discovered that producing the screened panels myself has been the best option for me.

The silkscreening process can seem very daunting and I personally found it that way.  Through trial and error as well as some online support I have managed to work out a process to create my own screens and screen the panels themselves and finally to drill out the panels for installation.  By keeping the items I require on hand I’m able to produce finished panels in a very short time (less than half a day).  This article is meant to share some of my experiences with other builders who wish to screen their own panels.

Before I begin I should note that the process I use is for MU (Moog Unit) format panels.  For MOTM style panels I have used FPD files and Front Panel Express where I have obtained excellent results at reasonable costs (plus they ship gummi-bears with their orders).  Mmmmm gummi-bears.

The Screen

Following my adventures in having a local printing company screen the panels for me (at a very high cost) I decided to screen panels myself.  I purchased panels from Synthesizers.com so I could be sure the size and quality was spot on.  The next step was to obtain the silkscreens with the images of the panels which I produced using Microsoft Visio.  I have been using Visio since it came out and I’m quite familiar with it.  I even created a small library of the shapes I frequently require.  These include knob graphics (0 to 10, -10 to 0 to 10, no numbers) as well as graphics representing jacks, LEDs, switches and more.

I found a company that would produce the screens for me from SVG files (Standard Vector Graphic).  Because of the fine lines and small letters and numbers used on the panels I chose a screen mesh count of 230.  That is 230 threads per inch.  Lower mesh counts work but like lower resolution on monitors, fine images get a chunky, unappealing look.

The trouble I encountered was that the screen production company was manipulating the graphics files I was sending.  This was mainly to fit two panel images on a single screen.  In several cases the graphics were not lined up correctly or some of the text and images were changed or omitted.  Vertical text sometimes had words run together despite the original version being correctly and meticulously laid out. The biggest problem for me, however, was the large cost of shipping the screens.  Some of the screens were used for personal one-off panels and these once again made the process less than cost-effective.

The process of creating my own screens seemed daunting but after a bit of trial and error I’ve been able to do it with good results.  The first step was finding a company to purchase the screens from.  I located a company just outside of Toronto (I live about 100 miles north of the city in a rural area).  They provide ready made screens in the mesh density I desire.  I use a standard 20″ x 24″ framed screen.  They also sell the emulsion, emulsion remover and other supplies necessary to produce the screens.

I should mention that I first tried using my own hand made screens along with a kit I picked up at a local art supply chain (Michaels here in Canada).  The kit was by a company called Speedball and it contained small sizes of emulsion, remover and a screen (110 mesh count).  I had also purchased some squeegees spatulas and a roll of 230 mesh from a mail order house to make my own screens with.  I purchased some small framed canvases at the art store, removed the canvas and stapled the 230 mesh to the empty frame, stretching it tightly.  While this did work out the tension was nowhere near what a good quality screen should be so after making a couple of panels with this setup I switched to professionally stretched screens.

Emulsion

When I made my mail order purchase early on in my learning of the process I also purchased some film emulsion.  This could be cut to size then applied to the screen with a two step spray on adhesive.  I thought this would be easier than the process of using liquid emulsion.  It wasn’t.

The Speedball emulsion that came with my kit was far easier to use.  The emulsion is mixed with an activator when first opened.  The mixed solution can stay usable for several months if refrigerated and even with the small quantity contained in the kit I was able to produce several screens.  After running out of the Speedball emulsion I switched to Chromaline UDC-HY.  I was able to purchase a larger quantity of it for a much better price.

While the best way to apply the emulsion to the screen is with an emulsion applicator ( a trough-like device that evenly spreads a thin layer of emulsion) I was able to use a 9″ squeegee with a good degree of success.  Remember to keep the layer very thin and very smooth.  Any imperfections will affect your screening process.

Make sure to allow the emulsion to fully dry before proceeding and keep the emulsified screen in a dark place once it’s dry to prevent exposure.  I would apply the emulsion in a lighted room but once the emulsion was applied I would move the screen into a dark room to dry and then transfer it to a closet until needed.  Using a red LED light bulb in that room was handy for avoiding bumping into things in the dark.

It’s also a good idea to have emulsion remover on hand in case your emulsion job goes awry or in case you just want to reuse a screen.  This is typical when making a single screen  for a single, one-off panel.

The Film Positive

To create the image for the screen I printed my graphics onto transparency film.  This is called a Film Positive.  The transparency film is available at your local office supplies store.  It costs a bit of cash but is well worth it.

While there are many types of professional films for Film Positives I’ve found that regular transparency film works fine.  The critical thing to make sure of is that your inkjet printer has a good, full black ink cartridge.  If the image printed is not solid enough light will pass through during exposure causing a poor screen image.  I’ve tried using two copies of the same transparency laid atop one another and taped on the edges but this can cause distortion if the two transparencies aren’t perfectly aligned.  Generally a single well printed transparency will work just fine.  Make sure your inkjet’s black toner is fresh and well topped up and that the print head is clean.  Be sure to let the ink dry before moving around the output as well.

Oh, one last tip;  some transparency film comes with a white strip on one edge for handling the transparency without getting fingerprints on it.  I recommend cutting this off with an Exacto knife (or similar) as it will create a big blank line on your screen into which ink may accidentally seep through.  Not critical though.

Exposure

When reading about the screen creation process I read a lot about light tables and other complex methods of exposing the emulsion to light.  I ended up finding a video that showed me how to create my own exposure lamp using some 2″ x  4″ wood and a halogen work light.  Even this is not fully necessary and exposure can be performed with good old sunlight.

I found this video online which was very helpful for building an exposure unit for an extremely low cost.

This exposure unit has worked great for me.

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My Exposure Unit With Black Cardboard Base

Exposure time is another factor when preparing your screen.  At first I would get exposed screens but the emulsion would not wash out of the printed area.  This was because I was exposing the screen for far too long.  I found that for my exposure unit and the emulsion I was using that four (4) minutes of exposure time was perfect.

I watched the following video to learn a technique to determine exposure time (the whole video is good although I’ve time indexed the exposure section)

Again, when working with the screen in preparation for exposure I had a red LED bulb on in the room just to prevent accidental exposure during handing.

The Ink

Finding the right ink was a challenge which turned out to have a very simple solution.  At first when I was having the screens done by a professional printing company they told me that a big part of the cost was in determining the appropriate paint to screen with as the surface was metal.

Actually the surface of the Dotcom panels is powder coated paint which holds the screened ink quite well.  When obtaining my own screens then experimenting with material I started with acrylic paints.  I chose acrylic because it was easy to handle and washed off with water.  If I messed up a screen I could wash the error away if I got to it within a minute or two.  Warm to hot water was good for this.  The trouble was the different paints I tried were all a bit too runny and yielded poor results.

I finally tried Speedball Screen Printing Ink for Fabric (white).  This turned out to be an excellent choice.  The ink was thick, bright and was easy to handle and to wash off.  Remember to keep your squeegee, spatulas and particularly your screen very clean.

The real trick to ensuring good adhesion with the ink is in the curing process.  More on that later…

The Screening Table

While many sophisticated screening tables are available for big bucks I was looking for a more cost effective system.  Using some scrap wood, a pair of screws and (most importantly) two Butterfly Hinges ($5 each) I fashioned a device which would allow me to screen my panels.  The system works just fine for single colour screens and while I wouldn’t recommend it for high-volume production it works great for small quantity panel creation.

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Some scrap wood, Butterfly Clamps and two screws – that’s it!
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Here is the unit with a screen installed

The screen itself should be about 1 millimetre above the panel itself.  This allows only the portion of the screen under the squeegee to be touching the panel at any given moment and avoids smearing.  I use a pair of screws in the table which the frame of the screen rests on.  They are positioned at a depth allowing this 1 millimetre gap.

The Process – Part 1: Emulsifying the Screen

Mix the emulsion with the activator according to the instructions for your particular brand of emulsion.  Mark the container with the date so you’ll know when it expires as you don’t need a whole lot of it for each screen.  I use a large Zip-Lok bag to store the container in the fridge after I’m done.  The bag prevents stray emulsion which may have got on the container from dirtying the fridge and getting my wife angry with me.

The emulsion may stain plastic wash sinks if left for any length of time so make sure to have a source of water and scrub brush handy.  Latex gloves are also a good idea.  I have a short length of hose with a garden spray nozzle connected to my sink to add some pressure.

Since I don’t have an emulsion applicator I use a squeegee to apply the emulsion to the screen.  Emulsion is applied to the bottom side of the screen.  That is the side the screen is attached to frame.  The side that makes contact with the panel.  Apply a thin even layer to the screen.  If you have to go back and forth just make sure the layer is even and smooth.  I don’t cover the whole screen as I’m only using a panel-sized graphic (smaller that 8.5″ x 11″).

When I apply the emulsion I squeegee the emulsion right off the edge of the screen into a large aluminum tray that I place in my laundry room work sink (see: keeping the wife happy).  I can then recover the excess emulsion and return it to the container before refrigerating it for storage.  Plastic paint spatulas are ideal for this.

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My Drip Tray With a Handy Warning

Once satisfied with my layer of emulsion I place the screen bottom side up on a table in my dark(ish) room with a fan which gently blows across the surface.  If the layer of emulsion is thin and even it should dry in one to two hours.  If you have a bead of thicker emulsion down the sides of the emulsified area (caused by the edge of the squeegee) I carefully remove it with my paint spatula to avoid a wet thick section which takes longer to dry.  Just make sure not to muck up the smooth centre area where the panel image will ultimately go.

Once dry you can either proceed to the next step or store the screen in a cool, dry, DARK place until you need it.  Sometimes it’s handy to make several screens if you plan to create a bunch of different panels.

The Process – Part 2: Screen Image Creation

Double check, then triple check your image ensuring the spacing is correct, fonts are suitable and that the spelling is correct.  Print on plain paper first and stare at your panel design.  Sometimes mistakes make it through to this stage.  Have someone else check it for you as a fresh pair of eyes can spot errors you miss or see logistical problems you didn’t foresee.  Also remember that you don’t want to print the image of the panel if you included that in your design.  You only want the text / graphics which will be screened onto the panel plus crosshairs for where drilling should be done.

Once the graphic is confirmed ready on your computer  print it onto transparency film.  Let the ink dry thoroughly once printed and avoid bending the transparency so that the ink doesn’t crack.

The next steps involve using the exposure unit I chose so this process may differ from other systems.  First, I place a piece of black cardboard (available at your local office supply store) across the bottom of my exposure unit.  This prevents light from bouncing back up and ruining the exposure.  Next I place the screen, bottom up onto the cardboard and place my film positive UPSIDE DOWN onto the screen.  It is upside down because when the screen is turned over it will be in the correct orientation.  Finally I place a piece of glass over the film positive to ensure firm contact between the film and the emulsion side of the screen.

And now… LET THERE BE LIGHT!  I activate the halogen light and at the same time activate a 4 minute timer.  Actually I have SIRI activate my timer.  At this point I also turn off the red light and turn on the room light.  After all, we are exposing using light so what the heck.

At the end of 4 minutes I immediately remove the glass and Film Positive from the screen and take the screen to sink where my hose and nozzle is set up.  Sometimes in the summer I do this outside.  Whatever you do, don’t dally (who talks like that anymore ; )

First I spray each side of the screen very quickly and for just a second in order to wet it down.  This starts the exposed areas to begin to appear through the emulsion.  Then after 10 to 15 seconds I begin to spray the screen to wash out the exposed areas.  Use only cold or lukewarm water (tending towards cold).  DO NOT USE HOT WATER.  I use the “Flat” setting on my nozzle which generates a wide, flat fan shape from the nozzle which has a good deal of pressure but not the heavy duty maximum pressure.  Spray from the top of the screen through.  You’ll be looking at the correct orientation of the text if you’re looking at the top (providing you didn’t screen the Film Positive backwards : ) You only want to wash out the exposed area, not blow all the emulsion off the other side.  You also don’t want to damage fine areas like lettering, numbers and knob graduations.

When done correctly you should be able to see through the mesh where the exposed areas have been removed.  There should be no emulsion remaining.  Watch for “cloudy” areas where a thin layer of exposed emulsion hasn’t washed off.  Again, be sure not to use too much pressure or to focus your water stream too much in one place or you could damage your work.

Once satisfied with the washed off screen I then place the screen back on my work table with fan to dry it off.  This only takes about 10 minutes.

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Not Totally Pretty But Perfectly Functional

The Process – Part 3: Screening the Panel

With the screen all complete it’s time to put ink to panel.  The frame of the screen must be snugly mounted into the Butterfly Clamps.  The important thing is that everything not move during the process.  Because I don’t use a specific positioning system when preparing the graphic on the silk screen I have to “eye” the location of the panel.

This involves carefully placing the panel beneath the graphic and carefully moving into the correct position.  I also use a pair of aluminum rails to help firm up the position of the panel once it’s in place.  This is a slow and carefully executed procedure.  I use duct tape to hold everything in position.

I’ve also found that if only the panel is used on the table during screening there can be some smearing at the top and bottom of the panel as the squeegee pushes the screen down to the panel at these points.  To prevent this I use 2 blank panels wrapped in cellophane (to protect them from stray ink) positioned at the top and bottom of the panel I’m screening.  This acts as a buffer so the panel is printed more evenly.

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When everything is in place I lower the screen and apply ink over the area of the panel.  This ensures that the ink will cover everything and will not rely alone on the squeegee process to spread the ink.  I also apply a bit more ink along the top of the panel to ensure that there is plenty of ink when the squeegee is used.

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The next part goes smooth and quickly;  firmly grasping the squeegee drag it down the panels (over the top buffer, down the main panel and across the bottom buffer).  Apply even pressure all the way and be deliberate.  Use a slight tilt to the squeegee so the edge of the rubber rather than the flat bit makes contact with the screen.  Don’t use too much of an angle though.  Don’t hesitate or lose your nerve during this portion of the operation.  If a mistake is made you’ll have a minute or two to wash the panel off and try again.  If everything goes ok (which after much trial and error it has been) then I lift the screen to check the panel then use my spatula to remove excess ink and place it back into the ink container.

The next part MUST BE DONE QUICKLY.  Get your screen, squeegee and spatula to your wash area.  Wash the screen thoroughly with cold or cool water.  Make sure to get all the ink out of the exposed areas to ensure the screen can be used again.  A thin scrim of ink will likely stick to a portion of the screen but as long as the exposed areas are clear you’ll be fine.  Warm or even hot water can be used to wash your tools once the screen is clean and out of the way.  If you wait longer than a minute or two to wash your screen there is a good chance it will be ruined so don’t hang around admiring your panel.  Once you check that it’s ok do your clean-up quickly.

But what if it’s not ok?  Something may have moved or perhaps your pressure wasn’t even.  If this is the case first carefully remove the panel from your setup.  You don’t want to mess up your positioning apparatus as you’ll have to put the panel exactly back into position for your next attempt.  After the panel has been removed quickly use your squeegee to cover the exposed area of the screen with a very thin layer of ink.  Don’t press hard with the squeegee as you don’t want the ink to go through the screen.  You only want to cover the exposed area so that the ink doesn’t dry into it while you’re washing your panel.

Take the panel to your wash area and use warm / hot water and even a light scrub brush to remove the ink.  This must be done quickly before the ink dries (on either the panel or the waiting screen).  You must then dry the panel thoroughly, re-install it in your table and repeat the screening process.  If it fails a second or third time you may want to remove the ink and execute the cleaning process on your panel, screen and tools before trying again.

It sounds complicated and takes some practice but with time you’ll find that it’s not that difficult and takes only a few minutes.

The Process – Part 4: The Curing Process

I like to ensure my ink has set firmly by “curing” my panels.  I use a toaster oven dedicated to this process as there is a smell and thin residue produced that I don’t want in my oven where my food is cooked (and again, I don’t want to piss off my wife).  I have found that 15 minutes at 320 degrees Fahrenheit  does the job just fine.  If you cure for too long or at too high a temperature the ink can turn an off-white brownish shade.

Finishing Up

The last part of the process involves drilling the panel, filing off the backside of the panel to remove burrs and then installing the components.  I won’t talk about this too much although I will say I recommend using a drill press and using pilot holes before drilling the actual holes.

So there you have it!

There are a lot of helpful videos on the Net which you may gain tips from which are helpful to your process.  I learned a lot from them.  I also learned a pile of info from Jeff at GuitarFool.com.  It was his site and his support that helped me get my screening project off the ground.  Thanks dude!

Remember that this is just “what works for me”.  There are many ways to skin a cat (sorry Wigglers) and you have to find the right technique to suit your personal needs.

 

Author’s Note:  I posted a link to this article on the Muff Wiggler DIY Forum.  If you’re not already aware, Muff Wiggler is the FINEST resource on the Internet for modular synthesizer enthusiasts.  There are some excellent points being made in relation to this article.  You might find it interesting to follow this link and read them for yourself.

Modular In The Lower West Side – One Year Later

As you may have read in this thread, modular synthesis, particularly DIY modular synthesis came to Lower West Side Studio in May of 2015.  The PAiA 9700 modular became the first truly analog modular synthesizer I had ever personally worked with.

Excited by this new / old technology I got more and more involved in the modular synthesizer world.  October 2015 marked the addition of a Synthesizers.com modular system and things took off from there!

The initial system consisted of the components required to build sounds;  MIDI to CV interface, Oscillators, Envelope Generators a Filter and a Voltage Controlled Amplifier as well as a Noise Source.  These modules lived happily in a Dotcom 22U walnut cabinet on top of which I stacked my PAiA 9700.

 

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The Synthesizers.com Modular atop the Moog Sub 37

Very soon after acquiring the new modular I got into the DIY world of building my own modules.  Numerous vendors produce modules for 5U / MU format synthesizers and I began to build a great number of them.

Here are some of the experienced I’ve had with my modular synthesizers as well as the world of DIY.

Formats

There are several formats for synthesizer modules with Eurorack easily being the most popular and providing the largest number of modules.  Personally though I prefer stick with (at least for now) the Moog Unit or MU format.  From a usability standpoint I like the large knobs and switches and the clean, consistent layout of the panels.  I also prefer the way that each module generally performs a single function.  I find that it makes creating and debugging patches easier.

Eurorack does have a lot to  offer though.  The small form factor makes portability very easy.  Coupled with the feature that modules often provide several functions per module you can take a lot of synthesizer with you in a compact case.  The jangley graphics, tiny knobs and inconsistent format don’t appeal to me but a huge number of synthesizer users out there really prefer it.  That is why the bulk of modules available are created for this format.

Cases / Cabinets

Presently my modular system is installed in walnut cabinets.  The first cabinet I received, a 22U (unit) cabinet, was from Synthesizers.com.  The quality and finish are absolutely beautiful.  The problem with living in Canada, though, is that when most of the gear is manufactured in the USA or overseas there is a large cost for currency conversion, HST (yes our greedy government takes a cut of merchandise not even sold in this country) and of course shipping.  Shipping 44U cabinets not to mention the other expenses makes them cost prohibitive.  My solution was to find a local carpenter who could produce the cabinets for me and match them to the Dotcom finish so the entire system would appear as a single unit.  Once I filled the 22U system over the Winter of 2015 / 16 I purchased a 44U cabinet for expansion.  After building several modules (more on that later) I filled the cabinet and by late summer I had ordered a second 44U cabinet giving me a total of 110U and a wall of modules.

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2 x 44U and 1 x 22U Cabinets Ready For Modules

One very critical point to remember is power.  My original Dotcom QPS1 power supply was not going to be able to power 110U worth of modules.  There might have been a chance it would as just because there is 110U doesn’t mean there will be 110 modules.  Running a power supply at its limit, however, does not yield the best performance so I replaced it with a QPS3 power supply.

As you can imagine this system is not very portable.  While it could be moved from location to location it’s not something I would really like to do.  For starters the cabinets are all bolted together so removing and reinstalling the connecting brackets would really wear and tear the wood.

Instead my plan is to build (or buy) a  portable cabinet.  I will use my displaced QPS1 power supply to power the unit.  With a portable I can install modules required to produce sound on the go (VCOs, VCFs, VCAs, a sequencer and support modules) while utilizing it set up next to my main modular unit when it’s not on the go.  The best of both worlds!

DIY

The Do It Yourself side of modular synthesis is very appealing to me.  I got my start in the computer field decades ago by building Apple Computer peripherals from the PCB on up.  Those skills translate very well into the world of DIY synthesis.  MU format modules generally utilize Through-Hole components which are easy to handle and to solder.

The first synthesizer in the studio, the PAiA 9700, was completely DIY and is an excellent way to dive head first into this area.  The 9700 is in FRAC format and while I was able to integrate the 9700 with my Dotcom modular through the use of 1/4″ to 1/8″ conversion cables it never seemed a true part of my system.  To remedy this I mounted the PAiA modules in MU format panels and replaced the 1/8″ jacks with 1/4″ jacks.  I also replaced the tiny potentiometer knobs with larger 1″ knobs (the pots stay the same though).  Overall the conversion was quite simple.

Building new modules turned out to be both easier than expected and quite fun.  There are numerous vendors providing Printed Circuit Boards (PCBs) for MU format or for multiple formats (which allows them to function in MU format systems).  The important thing is that they run on +/-15 volts which is what the MU format (with the exception of Moog themselves) utilizes.

The bulk of the modules I’ve built since beginning the DIY adventure are by Oakley Sound Systems.  I find their boards quite excellent to work with.  The quality of the boards, their clear labeling and good documentation makes them easy to build.  The best part is they sound and function outstanding.  I have also built numerous modules from Cat Girl Synthesizers.  The CGS modules are often quite unique and while not documented as thoroughly as the Oakleys are not too difficult to get completed.  Because both of these manufacturers produce DIY only products they are not as widely found as say something like Synthesizers.com or other vendors (Moon, STG, COTK, etc…) who only provide full working modules.  There are several companies (Lower West Side Studio for example) who will build these DIY boards for sale as completed modules.

I have also found some terrific vendors for DIY products.  While Oakley sells their boards directly to the end user products by CGS, Barton, Moogah, Yusynth (to name a few) can be obtained from companies like SynthCube.com or ModularAddict.com.  I’ve found both these vendors to be excellent at providing quality products for a good price and on time.

Now to the panels.  The toughest part of DIY modular synthesizer building I have encountered is obtaining panels for the boards once they are built.  Some companies such as FreeState FX and SynthCube.com sell finished, drilled panels for many popular modules.  I have used several methods in obtaining panels including having them screened at a printing company but all have been quite expensive.  I have been silk screening my own panels as of late and even produce the screens themselves.  I will be writing a detailed article on this aspect of synth building in the very near future.

 

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Oakley Discreet Ladder Filter Ready For Calibration

Modules

While most of my modules are built in-house I have a large number of modules which have been purchased ready-made.  These (so far) are all by Synthesizers.com.  There are a large number of MU format vendors out there but up until this point I have found everything I need with Dotcom products.  From their oscillators to their sequencers I have not found a module I am dissatisfied with.  Their products are excellent and their service and support is outstanding!

That isn’t to say that I won’t be buying modules from other vendors.  While a wide variety of vendors each make oscillators, filters, amplifiers, sequencers, mixers and other similar modules they are all quite different from one another.  In a way they are like cars.  Sure cars have four wheels, an engine and a steering wheel but they are still all quite different.  Similarly, different modules from different vendors all have their unique attributes.  Some, for example, are workalikes of modules by very well known and respected manufacturers such as Moog, ARP, Oberheim, Korg and others.  Other  vendors have their own take on how modules should sound and perform.  It is my desire to have a wide variety of modules from a large number of vendors to allow my modular to produce an extensive variety of sounds.  At this writing my modular, dubbed SWAN (Synthesizer With A Name), has six oscillators from three vendors and eight filters from eight vendors and five amplifiers from four vendors.

Oh… And The Sound!

While I have heard a large number of synthesizers in my experience, nothing holds a candle to the wide ranging capabilities of modular synthesizers (except maybe the Minimoog).  The extensive patching capabilities can’t be matched by slab synthesizers.  The ability to select just the right filter for just the right oscillator and just the right support modules in any situation gives these synthesizers an ability to produce sounds that can’t be beat.  Further, the degree of understanding that goes along with sound production grows as you delve further into each modules abilities.  You can visually follow the signal paths and alter the sounds as you see fit.  There are no rules for what can plug into what and therefore you can achieve sounds that are difficult or impossible to obtain otherwise.

Having said that, there is of course the difficulty in duplicating sounds once you’ve created them.  There are a wide variety of methods of documenting patches but sometimes even plugging the right cables into the right jacks and setting the knobs the way you’ve got them written down doesn’t cut it in reproducing the sound you originally documented.  Maybe the machine was on for eight hours when you first made the sound.  Maybe there was something electrical going on that affected your original sound.  Don’t get me wrong, patches can be reproduced, however, it’s not always a one hundred percent guarantee that if you document a patch you’ll be able to reproduce it.  That’s where recording and / or sampling the patch comes in very handy.  There is something to be said for the ability to call up a preset sound at the press of a button.

The Future

There are already several modules being built and on order here at Lower West Side Studio.  While there are still lots of spaces available in the 110U rack I expect them to fill up quickly.  Expansion will take place first in one portable unit but likely more will follow.  There are just too many cool toys out there to try out.  We will also be expanding our product offerings here at the Studio so remember to check out our products page and watch for new modules which are often hard to come by but available here.

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SWAN As Of October 2016 – One Year Into Modular Synths

Finally I should mention the greatest resource for the modular synthesizer aficionado ;  Muff Wiggler’s Forum.  Sure the name sounds a bit odd for a synthesizer group (read the backstory though, you’ll laugh) but there are a large number of extremely experienced and talented members who are very generous with their knowledge and expertise.  You’ll get your questions answered and learn a pile to boot.  Give the site a look and remember to keep on wiggling.

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Barton Visits The Lower West Side

For some time now I’ve heard the name Barton Musical Circuits in relation to the DIY modular synthesizer scene.  The trouble is that there is so much stuff out there I find myself inundated with a wide variety of vendors, products and technologies that I sometimes hear something then forget about it a short time afterwards having moved on to something else.

Fortunately the other day while surfing I came across a site which I had never found before.  It is a vendor called Modular Addict.  Intrigued by the name I began to check out their site.  Modular Addict officer a substantial number of DIY kits in multiple formats.  Under their Multiple / None format I found the Barton line of PCBs.  These boards were designed for the Eurorack format, however, it was my intention to modify them for the Moog Unit (MU) / Dotcom  format.  The boards can operate at 12 or 15 volts which is perfect as Dotcom utilizes + / – 15 volts.  The boards even support an MOTM style power connector.

I purchased three types of PCBs;  The BMC018 Analog Drum module, the BMC030 Guitar Interface module and the BMC034 Switched Resistor Voltage Controlled Filter module.  I figured this was a good place to start.

The boards arrived quickly and were packaged very well.  The cost of the boards was very reasonable which is great for something you’ve never tried out before.  I looked up some videos on the modules on YouTube and liked the sounds and functions the modules produced.

Documentation for the boards is available for download and is clear and easy to follow for the most part.  A bit more detail on the flying wires could be helpful but overall I was able to determine how to wire the jacks from the photos provided.

In order to accommodate the MU format I did have to wire the potentiometers with flying wires rather than using the PCB mounted potentiometers indicated in the documentation. This required an added level of complexity to the build but in reality is wasn’t difficult at all.

One thing I did notice from the photos was that the Ground (Earth) pins on the input / output jacks were not connected.  Personally I like my gear to be Grounded so when I wired up my modules I connected the Ground pins together and then to a ground point on the PCB.

I started by building the BMC030 Guitar Interface.  The build went quickly and easily and after a couple of hours I was testing the board with my modular.  It worked very well allowing me to change the sound of my bass guitar with the filters and other toys in my modular.

For my build, though, I had to design a panel suitable for my Dotcom style cabinet and modules.  I chose a 2U panel so that I could use the large knobs associated with MU / Dotcom style builds as well as having the components spaced out comfortably.  Once I had a design I used corrugated cardboard and a printout of the panel to create a mock-up.  This allowed me to test my layout and ensure things would fit.  As it turned out this test showed me that a couple of items needed to be moved a couple of millimetres one way or other.  I have made those changes and the panel is now ready to be sent to my silk screen guy to have a screen made.

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2U MU Version of Barton Musical Circuit’s BMC030

I did take the liberty of slightly modifying the name of the module from Guitar Interface to Instrument Interface as I plan to plug things other than guitars into it.  Just for fun!

Next I moved on to the BMC018 Analog Drum module.  This is a cool little module which allows you to create some really cool bass drum and tom sounds.  Coupled with some noise you can also create some interesting snare drum sounds.

Once again the build went quickly and smoothly.  The module tested out perfectly and I can definitely see adding a few more of these to my modular for some cool electronic drum sounds.

I created a 1U panel for this module which I mocked-up out of cardboard like the first module.  This time no adjustments were necessary.

MU Version of Barton's BMC018 Analog Drum Module
1U Version of Barton’s BMC018 Analog Drum Module

One question that did arise was Barton’s use of 10 Ohm resistors in place of Ferrite Beads to reduce power supply noise.  An interesting discussion sprung up from this subject on MuffWiggler’s Forum but in the end, for this first build at least, I decided to stick with the documentation and go with the resistors.  So far they seem just fine.

Next up will be the BMC034 Switched Resistor VCF.  I have several filters now and I’m very excited to try out another.  The different flavours filters give a modular make for a wildly varying sonic experience and I plan to add a large number to my setup.

Once I complete the next build I’ll post a write-up.

So in a nutshell;  modules by Barton Musical Circuits, in my opinion, are quite a nice addition to my modular rig.  I really like them in the MU format I have modified them for but even as Eurorack modules they are a great add-on.  I would also highly recommend them for beginner DIY builders as you get an easy build with some excellent features when you’re done.  Oh, and Modular Addict….. excellent place to deal with!

 

 

Cat Girl CGS01 Sub Oscillator

Actually the full name of the module is the Cat Girl Synthesizer CGS01 Sub Oscillator / Harmonic Sequencer…. but that is one heck of a long title.

The CGS01 is a tremendously powerful module whose capabilities are often not completely understood.  Truth be told I have yet to fully understand the module’s abilities but I hope to pass on what I do know with this article.

Several CGS01 modules have been built here in the studio.  The build is actually quite easy. That is they are easy up to the point it’s time to connect the flying wires.  Once you get the trick of where everything goes, though, the modules are a snap to build.

For the CGS01 builds the boards were purchased from Synthcube.com.  At the time of this writing Ken Stone, the board designer and manufacturer is no longer selling the boards through his site but his product line is available from Synthcube.com (at very reasonable prices I might add).

Cat Girl modules are among the most unique of the DIY modules out there.  First of all they  provide a wide and assorted array of features which are not otherwise available in modules by other manufacturers.  If the features are available Ken has put interesting spins in his version.  Second, CGS modules are frightening to build.  When I first came upon the CGS site and read Ken’s FAQ and disclaimer I practically ran away screaming in fright.  As a new DIY builder his warnings are very valid.  With some research and the excellent support of users on forums such as Muff Wiggler and Electro-Music I was able to successfully build several of his designs.

My first build was the CGS01 Sub Oscillator / Harmonic Sequencer which had some very intriguing features.  Rather than acting as a single sub oscillator which would play a note one or two octaves below the main oscillator’s note the CGS01 has a variety of divisions of the primary input note.  Further a combination of two inputs could be multiplied and divided then mixed together to produce even more interesting sounds.

In addition to these sound contorting features the CGS01 could alter control voltage inputs such as LFOs.  The output of these mashups could then be fed into an oscillator’s 1V/Oct input to create bizarre sequence effects.  This is a way cool feature!

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2 CGS01 Modules Built an Ready for Wiring

The largest number of components on the board are resistors, primarily in the mixer section. A few capacitors and some diodes (and 2 ferrite beads) make up the remainder of the small components.  There are 9 integrated circuits used but none of them are particularly expensive or difficult to obtain.  In short;  building the PCB is a snap.

Wiring the board to the outside world is a bit trickier.  There are a number of variations which can be done depending on how large a panel you wish to use, how many potentiometers you want and how complex you want your options.

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Ken’s 14 Potentiometer Design
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8 Pot Alternate Layout

To keep things within reason and to reduce the footprint of the module I decided to go with Ken’s alternate layout with replaces some potentiometers and a 5 position rotary switch with some toggle switches and a reduced number of pots.  I utilized a combination of Ken’s panel layout and one done by Kindredlost from Muff Wiggler to create my panel design which I silk screened onto a Q132 Double Blank panel from Synthesizers.com.

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My Test CGS01 Panel

The wiring diagrams on the CGS site are a bit confusing when it comes to wiring up this alternate panel layout so I created my own wiring diagrams for reference.

CGS01 - Page 2

CGS01 - Page 1

As suggested in Ken’s documentation I did not tie the flying wires together in my build to prevent cross talk so from the back the module is a bit less tidy than I like but we do what works rather than what is pretty.

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The CGS01 Wired Up And Ready To Test

 

Describing the features of the CGS01 doesn’t do the module justice so please watch the following demonstration video for more information.

So to summarize;  Great module.  Not as scary a build as you might think.  Incredible features with a multitude of possibilities.  Try one out!

Stroh Dual Gene Splicer DIY Build

Last week I received a Stroh Dual Gene Splicer kit from Synthcube.com.  This versatile module is actually two boards mounted in a single width (1U) MU panel.  The panel is by Caleb Condit and is laid out clearly and cleanly.

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Complete Dual Gene Splicer Kit from Synthcube.com

 

Each Gene Splicer provides two inputs which are mixed together and then sent to both regular and inverted outputs.  A control voltage can be used to pan between these two inputs.  Either audio or  control voltages can be input into the input ports.

If you’re new to DIY and looking for an easy place to start then this is the module for you.  The board consists primarily of resistors with a few diodes, capacitors and a single Integrated Circuit.  The interface to the outside world is through ten 1/4″ jacks.  There are no potentiometers.  Both boards are identical and can be built quickly and easily.

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Both PCBs Almost Completely Populated

Once the boards are complete it’s time to wire the jacks, install the board mounts and connect the power.  I used a single ground wire connecting all the jacks together then connected the ground to the ground on one of the PCBs.

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1/4″ Jacks Mounted and Ready to Wire

Rather than wiring headers onto each board I opted to solder wires connecting the power pads.  The board uses +/- 15 volts plus ground.  There are pads for both MOTM and Eurorack style power connectors.

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Power Wires Run Under The Boards

The kit comes with an MOTM to Dotcom power connector convertor but I opted to wire my own Dotcom style power connector directly to the board setup.  After soldering all the power wires to the board I connected the remaining flying wires to the 1/4″ jacks.  There are only 5 per board and the wiring went very quickly.  I opted to run the wires through the underside of the board to keep the build more clean.

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The Dual Gene Splicer Wired Up And Ready To Test

With the wiring all done the board was ready to test.  For testing I have a separate power supply which I use on untested modules prior to connecting them to my modular’s actual power supply…. just in case.  Once I confirmed the module was working I installed it in my cabinet.

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The Dual Gene Splicer Mounted In The Cabinet

The kit itself comes without documentation, however, the docs for this and other Stroh modules can be found here on the Muff Wiggler Forum.  The Bill of Materials is available in this thread.

To see the features of the Stroh Dual Gene Splicer check out the following video…

 

 

Sometimes Chaos Is Better!

There’s a saying with modular synthesizer users; You can never have too many VCAs.

Over the past few months I’ve really learned that’s true.  One corollary I’d like to add is that those VCAs should not be the same.  Having a variety of VCAs provides a wide range of sounds as each VCA adds its own subtle difference to the sounds it is processing.  As of this writing my modular has five VCAs; a Cat Girl VCA 3+, a PAiA 9710, 2 Oakley Classic VCAs and of course, a Synthesizers.com Q108.

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But this post is not about VCAs.

I would like to add the statement; You can never have too many VCFs.

Filters, like VCAs and Oscillators each have their own unique characteristics.  Sometimes you’re looking for a rich, creamy filter.  Sometimes it’s a raspy biting filter.  Sometimes it’s a warm and fuzzy filter.  In any case having a variety of filters to choose from just expands your creativity pallet.

Presently in my coral of filters I have; a Yusynth Minimoog clone filter, a Dotcom Q107 State Variable filter, a Synthcube / Moogah SEM filter, a Cat Girl Steiner / Synthacon filter, a DJ Thomas White Triple Low Pass Gate and (the actual subject of this post) a PAiA 9730 filter.

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As I add components to my modular I’ve learned that certain modules have a high degree of precision to them while others tend to have less.  Synthesizers.com modules, for example, have an almost surgical quality of beauty to them.  They have a degree of perfection I can always count on.  I know what to expect of them (most of the time).  PAiA modules, on the other hand, are different.  I’ve described them to others as modules with a handful of sand thrown into the works.  They have a certain degree of unpredictability that has a type of charm all its own.  You can never be 100% sure of what you’re going to get when you throw them into the mix.

Migrating my FRAC sized PAiA modules to MU (see previous posts) was a great thing for my setup.  I now incorporate them into far more patch setups than when I was limited to the number of 1/4″ to 1/8″ patch cables.  Because the 9700 has the basic building block component modules for synthesis I have a PAiA feature available through all portions of the sonic creation process.

The 9730 filter is an interesting beast.  It is sometimes maligned for its unpredictability.  The 9730 can often mangle a sound beyond what you thought you would expect due to functional limitations and / or anomalies.  I won’t get into those specifics here but you can Google them if you’re interested.

One “Fix” offered by PAiA is a resistor addition modification to minimize oscillation of the filter.  This involves tacking in a couple of 4700 Ohm resistors to IC3 on the board and resetting the scale trim pots.

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I performed this process and used it for a couple of months.  During that time I found I used the 9730 less and less.  It became so un-interesting.  The filter worked but without its wild unpredictability it left me flat and bored.  If I wanted a bland filter I would have searched out a bland filter (although why the hell would I do that ; ).  All my filters have unique characteristics which make me love them all.  Having worked with them for a while I now have a good idea of where to go when looking for a particular sound.  When looking for a wildcard I’d go to the 9730 (before the mod).  After the mod, however, it was just another filter and not a particularly interesting one at that.  Removing the modification changed all that.

My bandmate in my electronic band Fizzbin once said to me that he chose some of his effects pedals and synths based on their unpredictability.  He explained that not knowing what was coming could sometimes be more fun then simply dialling in a sound.  He’s right!

Un-fixing the PAiA was the best mod I’ve made in a long time.  I’m excited to have my out of control, whack-job filter back.  I wouldn’t have it any other way.

 

2015 – The Year In Review

I know 5 months into 2016 is a bit late for a Year In Review article but hey… better late than never.  2015 was a very interesting year to say the least.  Musically a lot of stuff was going on while some… not so much.  So here goes;

Drums / Percussion

Another slow year for the drum kits.  Once you have all the toys you need there isn’t room for much more.  I’m still using my Gretsch Renown Maple kit for studio use and my Pearl Exports (now 35 years old) for live shows.

I’ve played around with heads this year settling on a set of Evans Hydraulic Black for the Gretsch batter heads and continuing to used Remo Pinstripes on the Pearls while using Evans Hydraulic Blues on the resonant heads.  I tried the Hydraulics on the Pearl batter side, however, the sound doesn’t carry well in live situations.  In the studio the Hydraulics work great, especially for recording.

I also scored a great deal on a Pearl hi-hat stand for my gigging kit.  Pawn shops are awesome for gems like this and now I don’t have to tear apart my studio kit hardware when I gig.

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Setting Up For A Gig At Piper’s Sports Bar

 

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The Black Evans Heads Look Awesome and Sound Great

Electronics

2015 was a HUGE year for electronics as I have shifted my focus to DIY gear.  It started with stomp boxes from Tonepad.com.  These guys have some great clones of really excellent pedals.  I began with a Ross Compressor pedal which, after a bout of using bad solder, worked out really well.

Building electronics was something I did early on in my computer career.  My mentor Dave taught me how to build Apple 80 column clone cards, Z-80 cards and Hayes 1200 bps modem clones.  He was a strict teacher and my soldering skills are really good thanks to him.

Incidentally, if you’re into music DIY and haven’t checked out Small Bear Electronics then you’re missing out on some awesome stuff!

While I enjoy building stomp boxes I really put my skills to use in a new area which came to the studio;  Modular Synthesizers.

Modular Synthesizers

I’ve always been a huge fan of modular synthesizers.  There’s something about all those knobs, plugs and cables that appeals to me.  The sounds they create are astounding and in 2015 I finally got into them big time.

It started early in the year when I built a PAiA 9700 from a kit.  PAiA has been around for a long, long time as a DIY supplier.  I first learned of them back in the ’70s when I saw their Strings ‘n Things keyboard.  PAiA also created the first drum machine which was used in Peter Gabriel’s Games Without Frontiers.  It was only natural that I’d test my skills on one of their modular systems.

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The PAiA 9700 – My First Modular Build

I learned to create some incredible sounds with the 9700 and began to study the basis of synthesis itself.  From there I decided to move from the FRAC sized PAiA modules to the larger Moog Unit (MU) size modules which I’ve always liked the look of.

I discovered Synthesizers.com from where, in October, I purchased my first full size modular system.  I got only a few modules to start but the number of toys I added grew quickly.

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Synthesizers.com Modular Atop a Moog Sub 37

Following the addition of the “Dotcom” (as they are known in the community) I put my DIY building skills to use adding modules by Oakley Sound Systems.  Today the modular is quite different from the original version but you’ll have to follow the blog and read the 2016 Year In Review to learn about that : )

Incidentally, the PAiA and the Dotcom get along beautifully with some 1/4″ to 1/8″ patch cables.  In 2016 though there have been some format changes to the 9700 which you can read about in the blog.

Keyboards

Not much has been happening in the studio’s keyboard realm with the big focus being on modular synthesizers.  I should note, however, that I did take part in Moog’s Sub 37 Editor program.  Moog had been working on an editor for the Sub 37 synthesizer which has been released in 2016.  It’s quite a nice piece of software which opens up all sorts of possibilities with the synth.

I have to say though that while I really love my Sub 37 many of it’s features are “computerized” for lack of a better word.  Since working with the modulars I find I can accomplish more things more quickly without having to wade through menus and key combinations.

Software

Still working with Reaper and loving it!  They have a great upgrade cycle and terrific support.  I can’t recommend it more highly.

Bands

Coming of Age has had a great year performing many live shows at multiple venues.  We’ve done charity events and several private parties all of which seem to really have pleased the crowd.  Our repertoire of classic rock tunes has grown and everyone is having a great time.

Fizzbin is also expanding its musical field adding a number of original tunes to the list of songs we perform.  While we haven’t performed live during 2015 we are preparing an awesome show for the 2016 musical year.  Stay tuned!

So that, in a nutshell, was 2015 for Lower West Side Studio!  Sorry for the late entry but at least I got the info out there.  Keep on Rockin’!!!

 

System X ADSR – 5U Version

I’ve recently completed my build of a 5U version of the System X ADSR Envelope Generator by Frequency Central.  I have to admit it was a quick build and not very difficult.  I would definitely recommend it for those interested in getting into modular synthesizer DIY.

I ordered both the PCB and the panel from Frequency Central.  The panel is an MU style panel which sits perfectly in my Synthesizers.com style cabinet.  The panel design is by Caleb Condit.  The PCB is designed to accept either MOTM or Dotcom style power connectors with +/- 15 volts.

Board quality is quite excellent and very easy to work with.  The board is double layered and very clearly labeled.  The components are quite standard and I was able to build this project with items I already had in inventory.  The only items which I did not have were the potentiometers.  I ordered these from Tayda Electronics as they were not available at my normal component suppliers DigiKey or Mouser.  The parts arrived within a week though so the build wasn’t slowed down too much.

The module is very easy and straightforward to use.  As the name implies there are controls for each Attack, Decay, Sustain and Release.  There is also a switch for selecting Fast or Slow envelopes.  There is a gate input and both normal and inverted outputs.  These features together provide some very cool options for creating interesting effects.

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The Completed System X ADSR
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Populated PCB With Dotcom Power Connector
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Mounted In Cabinet

 

The following video demonstrates the use of the Fast / Slow switch on the Envelope Generator…

More PAiA 9700 5U Retrofits

The retrofit of my PAiA 9720 Dual Oscillator / Modulator went really well.  My Moog Unit (MU) style modular synthesizer is growing and the mix of different manufacturer’s brands of components lends to it an eclectic mix of sounds.  While I really love my Synthesizers.com components I’d like to mix up the sounds produced by my modular by integrating modules from a wide variety of manufacturers.  Having started my modular journey by building a PAiA 9700 I definitely wanted to include it in that mix of modules.

At first I integrated the 9700 with crossover cables.  The were cables with 1/4″ jacks on one end and 1/8″ jacks on the other end.  I got some really cool sounds.  The PAiA modules are grittier for lack of a better word.  They sound sort of like a handful of dirt was thrown into them giving them a more unpredictable sound and feeling.  Perhaps this is because of the use of 5% resistors throughout rather than the more conventional 1%.  It allows for far more drift from the designed specification.  Whatever it is I liked the result and wanted to integrate the PAiA modules more fully with my modular.

As mentioned earlier this conversion began first with the 9720 Dual Oscillator / Modulator.  This conversion brought the number of oscillators in my system up to five.  Having five oscillators in a system has allowed me to produce some damn cool sounds.  I intend to double it before I’m finished.  I was now left with the 9700K MIDI2CV8 converter, the 9710 VCA / Modulator and the 9730 VCF / Modulator.  The nice thing about the PAiA modules is that most include an Attack / Release (AR) or an Attack, Decay, Sustain, Release (ADSR) modulator (or envelope generator).  This flexibility gives the PAiA modules the capabilities of multiple modules.  While the cramming of features into a single module is more of a Eurorack thing it does sometimes come in handy.  The modulators are normalized on the PAiA modules which mean they are tied into portions of the modules circuitry without the need for patch cables.  This normalization, however can be broken through the insertion of a cable into the modulator’s output.

As with the 9720 module the 9710 and 9730 modules only require a slight modification to  support the Synthesizer.com’s +/- 15 volt power supply.  This modification involves first removing the R1 and R2 resistors and replacing them with straight wire link jumpers.  I just used left over pieces of component clippings for this.  While you can short the resistors by just wiring one end of the resistor to the other there will still be resistance on the circuit as some of the electricity will pass through the resistor so I opted to remove the resistors entirely and add the jumpers.

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R1 & R2 (Lower Right) Resistors Replaced With Jumpers

The second step in the power modification involved replacing the 4-pin power connector with a 6-pin Dotcom compatible connector.  The PAiA modules use +15 volts, Ground, Signal Ground and -15 volts.  To add the new connector I simply cut the existing 4-pin connector wires around mid-point and added my 6-pin connector.  Because the Dotcom power supply only has a single ground connection I soldered the Ground and Signal Ground cables together and then linked them to pin 4 (Ground) of the Dotcom connector.  Remember to remove pin # 2 on the connector you use so that it will mate correctly with the Dotcom power supply connector where pin 2 has been filled in for correct orientation.

I should note that I made and tested these power modifications prior to removing the panels from their original FRAC settings.  This way if for some reason the modules failed to function I far less troubleshooting to do than if I had modified everything at once and then tested.  Once I was satisfied that the modules worked with the Dotcom power supply I continued my modifications.

You may have noticed that I didn’t include the 9700K MIDI2CV8 module in the list of modules to which I made this power conversion.  This is because modifying this particular module is significantly different.  While the 9710, 9720 and 9730 modules sit downstream from the 9700K the 9700K itself is connected to the 12VAC wall-wart power supply and supplies the other modules with power.  In order to make the necessary modifications I referred to the Powering the 9700K MIDI2CV8 document provided by PAiA.  This document can be found here.  In a nutshell the modification involves replacing the power connector, rerouting a capacitor, removing the 7805 voltage regulator as the Dotcom supply has its own +5 volt pin required for IC3 (this reduces the power draw by a factor of 10), routing +5 volts to the board and modifying the existing power switch.  This last step is important as the switch cannot simply be removed. The 9700K requires a reset to get things going.  This reset was automatically accomplished with the switch was flipped to activate the power.  I replaced the switch with a momentary pushbutton switch.

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Note the Routing of the Yellow (+5) Line from the Power Connector

When transferring the 9700K to a new panel I decided to leave the board’s connectors in their original positions.  This meant drilling out the panel so that the board could simply be mounted in place while allowing access to the MIDI IN, MIDI THRU and DIP switches.  The tricky part was the DIP switch hole which is rectangular rather than round.  For this I drilled out small holes inside the rectangular area and filed it into shape.  My result is not perfect but it works ok for me.  Additionally because the functions of the output jacks varies based on the positions of the switches I opted not to screen the panel but rather refer to a cheat sheet for the functions of the jacks.

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Modified PAiA 9700K Mounted In the MU Modular

 

Speaking of panels…. Rather than pay wild fees to have a single panel screened by a printing company as I did with my 9720 I opted to have a silkscreen produced for each the 9710 and 9730 modules.  This worked out both good and bad.  The screens produced by Metro Graphics in British Columbia were excellent, however, my silkscreening ability is still lacking.  The results I got for the panels were acceptable for my own use but I wouldn’t produce them for sale until I’ve worked out the kinks.  Some things I’ve learned include; keep the screen about 1 – 2 millimetres off the panel itself.  Cover the area to be screened with a layer of paint prior to using the squeegee.  Apply EVEN pressure using both hands when using the squeegee.  Press hard.  In addition the acrylic paint that I’m using may not be ideal and I’m still searching for the best paint for the job.  As you’ll see from the photos the screening isn’t great but as I said… it’ll do for my personal use.

Once the power modifications were done and the panels screened and drilled it was time to  transfer the modules.  The biggest cost for the job was the 1/4″ jacks.  These panels have LOTS of jacks.  The 9730 has sixteen jacks and the 9710 has thirteen.  I used Switchcraft 112AX jacks.  These are 3 connector normally closed jacks.  I could have gotten away with 2 connector jacks for many of the connections but I got a better deal buying the jacks in bulk (for this project and several others I’m currently working on).  Two of the jacks are actually stereo jacks used on the 9710 VCA.  I began by connecting the jack’s ground lugs all together.  The PAiA FRAC modules have some funky methods of connecting the jack grounds to the potentiometers.  By linking all the jack grounds together it became much easier to connect the few pot grounds to the jacks then back to the board.

Once that was done I desoldered the flying wires connecting the 1/8″ jacks to the PCBs for each of the boards.  I should note that I did one complete module at a time rather than complicate things by doing the modules simultaneously.  Then I removed the potentiometers from the FRAC panels and separated the boards and panels.  For all but one connection (the Pan knob on the VCA) the potentiometer wires interconnecting one another did not have to be cut.  Only one or two ground wires linking the pots to the 1/8″ jacks had to be cut and these were easily reconnected to the new 1/4″ jacks as the jack grounds were all linked together.

I used the PAiA Illustration Supplement for each module to guide the re-wiring process.  I first connected the required resistors, capacitors and bridge wires to the necessary jacks before attempting to wire the flying wires to the panels.  This made soldering things in place much easier.  I then mounted the potentiometers to ensure everything fit into place nicely.  The next step was to connect and pot grounds to the jacks to ensure everything was grounded correctly.  Finally, following the supplements, I connected the flying wires to their respective sockets.  Once again, as with the 9720 VCO, the wire lengths were sufficiently long that they reached their target jacks without extension or replacement.

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9710 VCA Refitted

I did have to remove each module’s LED and add some flying wires to the PCB so the LEDs could be relocated to accommodate my panel design.  Just for kicks I used blue LEDs for the PAiA modules making it easy to locate them in the dark.

Once done each panel was tested using a bench power supply before connection to the modular’s Dotcom QPS1.  If I made a mistake the bench supply would take the hit rather than my production machine.  Fortunately each module worked perfectly and I installed them into the modular after calibration.

So now my modular has the added bonus of some PAiA modules plus I now have 2 MIDI to CV modules allowing me to run my keyboard to some oscillators and an external iPad based sequencer (I still don’t have a sequencer module) to other oscillators.  I’m very pleased with the result!

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5U 9730 VCF / Modulator
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9710 VCA – Note the Right Side – Apply EVEN pressure when Screening

 

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PAiA 9720 5U Retrofit

PAiA 9720 5U Retrofit

Last year I began my adventure into the world of modular synthesizers by building a PAiA 9700 modular synthesizer.  The 9700 is a DIY kit consisting of a MIDI to Control Voltage Converter, Voltage Controlled Oscillator / Modulator, Voltage Controlled Filter and Voltage Controlled Amplifier.  These are the basic building blocks of synthesizers whether  modular or all-in-one units.

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9700 Connected To Roland A-300 Pro MIDI Controller

There are several different size formats for modular synthesizers;

Eurorack is by far the most popular.  The modules are 5.06″ tall, utilize 1/8″ connector jacks (like iPhone headphones), are crammed with features and have very colourful and busy faceplates.  They also run on +/-12 volt power supplies.

Moog Unit modules or MU (or 5U) are based on the early Moog Modular synthesizers.  The modules are 8.75″ tall with varying widths.  MU modules use 1/4″ interface jacks (like guitar cords).  They tend to have a more uniform and conservative appearance as well as larger controls with more space between them.  Most modules have one or two specific features.  MU systems generally operate at +/-15 volts.

The PAiA modules are in FRAC format.  These modules are 5.25″ tall and like Eurorack utilize 1/8″ jacks while cramming lots of features and small controls onto each module.  These modules are designed for +/-18 volts but can operate at +/-15 volts with slight modification.

This is a very basic outline of the various modular formats.  For more information you can follow this link.

Each of these different formats can work together providing you use the correct cable types.  Each format, however, must have its own appropriate power supply.

Personally I prefer the Moog Unit format.  I like the clear, clean, consistent design of the panels.  I find the larger plugs and knobs easier to handle and I find their overall appearance quite impressive.  Late last year I began to build a new modular synthesizer by Synthesizers.com.  In addition to the Dotcom system (as they have come to be known) I also build DIY modules by Oakley Sound Systems, Yusynth, Cat Girl Synth, Moogah and others.  These modules provide the basis for a very powerful sound sculpting platform.

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I wanted to make my existing PAiA system part of that platform.  At first I tested the two systems together by cross patching them.   The two modulars work well together but what I really wanted was full integration.  While surfing the web I ran across a modular builder at Guitarfool.com.  He had created custom made panels for his PAiA 9700 modules and remounted the PAiA electronics into these panels as well as replacing the 1/8″ jacks with 1/4″ jacks.  I got in touch with him and he outlined some of the things he had done as well as providing me with his panel graphic.  Thanks for all your help Jeff!

The first module I wanted to convert was the 9720 VCO.  This module is actually two Oscillators and an Attack / Release Modulator.  I made some modifications to the graphic and had a panel screened.  I used a Synthesizers.com Q133 quad panel.  This ensured a consistent look for the modular and a proper size fit.

The next step was to prepare the 9720 to accept +/- 15 volts as output by the Dotcom’s power supply.  This involved removing R1 and R2 on the 9720 and replacing the resistors with a piece of wire.  You can also connect wires between the resistor points to short them out, however, leaving the resistors in place means that there will still be resistance along the electrical path.  Thanks to Scott at PAiA for clarifying this info.  Finally I replaced the power connector with a Dotcom compatible connector.  Both ground lines from the 9720 must be connected together then connected to the Dotcom’s single ground line.  With this done and tested the time had come to swap panels and jacks.

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9720 Modified For +/-15 (Note: Power Connector And Blue & White Wires In Upper Left)

 

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New Panel (Prior To Hole Drilling) Next To Existing 9720

 

Disassembly didn’t take very long.  Fortunately the potentiometers did not require having their flying wires desoldered which saved quite a bit of time.  Some of the pot to pot connections had to be severed due to length constraints then reconnected once moved.

Because the jacks were all being replaced I desoldered all the flying wires connected to each 1/8″ jack.

Following PAiA’s build document for reference I first added the new 1/4″ jacks, connected the ground leads and then (after repositioning the potentiometers) began connecting the specialty connections such as the capacitors, resistors and cross connections between jacks.  I then ensured that all the connections to the potentiometers were back in place.  Finally I soldered the flying wires back to the new 1/4″ jacks.

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Rewired 9720 Panel

With the system rewired I first tested the module on my bench power supply.  I highly recommend a separate bench-test power supply to anyone doing DIY modules.  In case something has gone terribly wrong the bench supply will short out rather than your modular power supply and any of your modules.  Personally I think it’s worth the extra expense.

With the module tested and working it was time to install it in my modular.

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New Panel Integrated Into Modular

My inventory of 25mm knobs was low but I plan to replace all the knobs so that they match the rest of my modular.  The larger knobs are also much easier to manipulate than the tiny PAiA knobs.

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S.W.A.N. – Synthesizer With A Name

I’ve already designed a graphic for the PAiA 9710 VCA which is my next conversion project.  Before that though I have a few new modules to build.

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5U design for 9710 VCA

EDIT:  VCO with nice chunky 25mm knobs

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