Posted by: Rich Sherkin | January 23, 2016

Yusynth Minimoog VCF

So far 2016 has been a great year for DIY modules at Lower West Side Studio.  Following the successful build of a Moogah SEM VCF I built a module that I’ve wanted since the moment I saw it; the Minimoog VCF clone produced by Yusynth.

There is nothing like the sound of a Minimoog and that is largely because of its transistor ladder filter.  Yusynth created a circuit based on the original and, like many of his other modules, he has published details on how you can create your own PCBs and build your own modules from scratch.  Unfortunately he does not sell any of his products.

Fortunately for me I didn’t have to etch my own PCB. came to my rescue by having some of these PCBs in stock!


The PCB quality was quite excellent.  Very well made and very clearly labeled.  The build documentation for the board, however, is pretty much non-existent.  Yusynth has a page on their site detailing the Bill of Materials along with some very detailed images of the board, component layout, off-board wiring and of course the schematics.  If you’re hoping for a step-by-step instruction manual though, Yusynth boards are not for you.  They are more of an intermediate to advanced build.  Yves detailed diagrams are excellent though and I had no problem putting the board together.


While the Minimoog filter is not particularly complicated there are a couple of things to note; there are six BC547 transistors required and these must be matched pairs.  In addition the four 47nF capacitors must be matched to within 1%.  To match the transistors I built a simple breadboard transistor matching circuit.  I used a circuit based on Ian Fritz’s design.

After selecting the correct pairs of transistors and group of capacitors my build went quickly and smoothly.

Once I completed the build I came to the part of DIY synth module building I dread… the panel.  Yusynth provides images for producing silkscreens of the panel, however, presently my silkscreening process is not up to snuff.  This was horrible.  I had a completed, tested working module but no panel to mount it in.


Then I discovered Free State FX.  They are builders in the US who provide panels for a number of Yusynth modules including the Minimoog Filter.  While the Canadian Dollar is very weak as of this writing the Free State FX panel was still significantly less expensive then the panels produced for me by a local screening company.  I received the panel very quickly and the quality was really good.  I should note for all those who do not wish to build their own Minimoog Filter module that Free State FX produces a built version for sale.


Mounting the board into the panel went very smoothly and it was soon connected to my modular for testing.  It works great!  I still have to run the calibration procedure to ensure it tracks volts per octave correctly.  Additionally frequency and emphasis adjustments have to be calibrated.  At this point though I’m extremely happy with the module.

One very nice feature about the Yusynth modules is that they run on 15 volts and utilize a power connector.  This makes for quick and easy installation in my modular synthesizer.  One thing I should stress is the importance of a bench power supply for testing modules before installation into the main system.  It costs a bit extra to have a power supply that only comes out for builds but in the event of a build error it can prevent your modular’s power supply and modules from being damaged.  I use a QPS2 desktop power supply for this purpose.

I’m very excited to have this module as part of my modular synthesizer.  I plan to add several more Yusynth modules to my rig in the near future!  Thanks to Yves Usson for the excellent design and to for stocking the part.

Stay tuned for sound samples…

Posted by: Rich Sherkin | January 22, 2016

Moogah SEM VCF

I recently completed a build of an Oberheim Synthesizer Expansion Module Voltage Controlled Filter work-alike produced by Moogah (Jeff Farr).  I picked up the panel plus PCB package from

I’ve always been a fan of Oberheim gear from way back in the ’70s.  Geddy Lee from Rush was probably my first experience hearing an Oberheim (at least I knew it was an Oberheim that I was hearing).  In fact Geddy had a Moogerheim mashup.  One very cool feature of the Oberheim’s were their filters which, as I began to understand the workings of filters more and more as my modular synth experience grew, I decided I wanted to add to my modular rig.


Geddy and his Moogerheim

A very cool feature about the Moogah SEM VCF was that Jeff Farr got Tom Oberheim’s blessing for his design of Tom’s circuit.  The VCF is a 2-pole filter which runs at either 15 or 12 volts (based on a couple of resistors).  There is no V/Oct control voltage so like the original it will only track a few octaves.  There is also no control voltage for the resonance (like the original), however, there is an option to build this in.  The PCB includes locations for the appropriate circuitry, however, the pre-made panels do not include a location for the required potentiometer and input jack.

Wanting my VCF to be as close to the original as possible I opted for the build without the voltage controlled resonance.  There are presently two panel formats available for purchase;  Eurorack and Dotcom/MU.  Because my modular is Dotcom based I opted for the Dotcom panel with the 15 volt power option., the online supplier of the board and PCB, has a nice panel designed by Caleb Condit.  The panel is made from anodized aluminum and illustrated using the metalphoto process.  It is manufactured in the US.  While I really liked being able to purchase the panel with the board both the design and illustration left me a bit flat.  The panel is painted with a flat black paint which tends to show fingerprints more than its Dotcom counterparts.  The white printing is more off-white and significantly less bright than silkscreened panels.  The design, while functional has more of a Eurorack disco feel to it.  I like my potentiometers labeled with numbers rather than cryptic shapes.  Please note that these are only my personal preference.  The panel is well made and just receiving a panel with the PCB was a blessing.  There’s nothing worse than having a circuit built with no panel to install it into.


The finished SEM VCF (Centre) among Dotcom panels

The SEM VCF is by no means my first, second or even fifth build.  I am not a skilled electrical engineer by any means although I do have relatively good soldering skills.  That said I must point out that this project is definitely NOT FOR BEGINNERS!

Step 1 in the documentation reads “The PCB requires a trace cut to address a design issue”.  YIKES!  That was a new one for me and definitely a bit scary.  The documentation, however, clearly shows where the two traces must be cut.  It also suggests to use a continuity tester to ensure the traces are cut.  I cannot recommend this step enough.  Just because it looks cut doesn’t mean the connection has actually been severed.

Cutting traces often involves adding jumper wires to reroute the flow of those cut traces.  This board is no exception and two jumpers are added later on in the build at step 22 of the manual.  This is a bit of a tight solder to points on the op-amps as they are close to some SMT caps.

Speaking of SMT or Surface Mount Technology caps – these suckers are SMALL.  VERY SMALL!  Normally SMT components are installed by machines.  They allow us to have very tiny devices like cell phones.  Soldering them by hand is a difficult process but not impossible.  It takes patience and a steady hand.  As my first attempt I can say that while not perfect, I did ok.  There is a handy video from Colin’s Lab showing how to solder SMT devices.  In addition – get smaller tweezers than the ones shown below!


Next to my index finger and tweezers – this thing is small!


The PCB quality of the the SEM VCF is quite good, however, unlike several other boards I’ve used the components aren’t marked by their reference numbers (e.g. R1, R2, C15, etc…).  They are, however, marked with their component values.  This makes it a bit trickier locating their positions especially as some of the labels are obscured by the through-holes drilled into the board.  Several of the labels are marked with dollar signs ($) to indicate that they are required for building the version of the board which includes the resonance control voltage.  Others are marked with asterisks (*) to indicate they are to be excluded for the CV resonance version.  Overall though I found it easy to locate the component spots and to populate the board.


The documentation for the project is quite good with one exception;  it is only for the Eurorack build.  While there is reference to which resistors to install depending on your power supply’s voltage, 12 or 15 volts (step 8) there is no warning about soldering the potentiometers to the board for the Eurorack panel (step 18).  I didn’t catch this at first and had to desolder my potentiometers.  What a freaking nightmare.  All went well though and I attached flying wires to the three potentiometer locations for the pots.  While a separate documentation is not necessary for the 5U build of this project it would be helpful if the author could mention the slight differences in the builds for the reader.


Pots soldered on before removal


After desoldering replaced with flying wires

Obtaining parts for the build was not too tough, however, there are three 2N4302 transistors which are discontinued and a bit tricky to find.  I was able to find work-alike versions of these transistors from Small Bear Electronics.  Incidentally, Small Bear is an AWESOME source for components for many DIY projects!

Another VERY important note is that if you are using the provided spreadsheet Bill Of Materials there is an error on row 25.  The Poly Cap listed is 150nF (nano-farad).  It should be 150uF (micro-farad).  Big difference!  This is corrected in the Bill Of Materials contained in the build document, however, not on the spreadsheet.

As I mentioned earlier, having the panel to install the board onto immediately after it was done was a tremendous advantage.  Once completed I tested the unit with my bench power supply.  I cannot stress enough the need for a bench power supply.  If a mistake was made on the board I would much rather blow up a bench supply then the power supply in my modular and also risk taking some modules with it.  I use a QPS2 desktop power supply.  I’ve also modified one of the power connectors to support a MOTM/Oakley style connector.  This allows me to test both Dotcom and MOTM/Oakley modules with no muss nor fuss.  The VCF utilizes an MOTM/Oakley style power connector.  Once tested I built MOTM to Dotcom connector convertor and installed the unit in my modular.


Setup and ready for testing

So there you have it!  A very cool module built in about two days.








Posted by: Rich Sherkin | December 5, 2015 Meet Oakley

The world of modular synthesis is incredibly fascinating.  There are so many different modules from so many different vendors which allow one to mix, match and manipulate sounds and signals in unlimited unique ways.  Each modular synthesizer can be an individual design limited only by the builder’s imagination, capabilities and of course…. cash ; )

For me, building modules from scratch is as much fun as buying them as complete units.  Fortunately the modular world has divided itself into various form factors permitting the artist to chose which size, Frac, Eurorack, MU (Moog Unit) and MOTM, they wish to pursue.  Many DIY vendors provide boards which can be installed in multiple sizes.  Personally I prefer the Moog Unit used by Moog and

One vendor who’s modules I quite like is Oakley Sound Systems in the UK. Not only does Oakley provide top quality PCBs for a variety of very cool modules along with excellent documentation and support, they also provide graphics which can be submitted to Front Panel Express for quick and (reasonably) cost effective panel creation.  As I discovered though, the panel graphics are suited for MOTM rather than Dotcom panel sizes.  While the panels are 8.75″ tall the MOTM panels are 1.75″ wide versus the the 2.125″ for Dotcom and Moog.  The upshot of this is that a gap will exist between modules when they are installed in a cabinet along with other Dotcom modules.  While blank space fillers can be used to bridge the gaps I was looking for a more visually appealing solution.

I decided that the best way to ensure the panels adhered to the Dotcom specification I purchased several blank panels from After looking at various options for labeling the panels including stick on labels and engraving, neither of which were very appealing I came across a synth-builder named Jeff from  He had built and modified a variety of modules which he then fitted into Dotcom panels which he silkscreened the graphics onto.  The result was exactly what I was looking for!

I created a template of the Dotcom panel from the specifications so kindly provided by Roger of  For this I used an old copy of Visio I had lying around.  Once I had the template I overlaid a JPG image of the Oakley graphics which I output from the Front Panel Design program.  Using this image on its own layer as a template I created new graphics using the fonts recommended by Roger for the Dotcom modules.  Now things started to look the same.

Placement of the drill holes was the critical factor.  Because Oakley modules use special mounts on the potentiometers to fasten the PCB to the panel (if you choose to build that way) the holes must be placed in exactly the correct locations.  Further, Oakley provides PCBs for easy wiring of the I/O sockets.  Like the potentiometers the user can opt to choose their own method of wiring them to the panel but I opted for the PCBs (the SOCK4 and SOCK8 panels).  Once again the holes must be perfectly aligned or the sockets will not fit correctly.

For my first run I found a local printing company who was up to the task of screening my metal panels.  While they did a very good job at the screening process the cost was very high.  So high in fact that I could have purchased all the screening gear I required and done it myself with screens left over to do more panels.  Well, everything costs the most during the prototype phase so I chalked it up to that.  In any case, the panels look good and despite a minor numbering error that I overlooked after they re-did my artwork the modules look great.

So now I’m in the process of obtaining the gear to do it myself.  As I plan to build a few modules and sell them I figure it will drive my build cost way down.

For now though I’m happy that the Oakley modules that I’ve built fit perfectly in my Dotcom cabinet!



Posted by: Rich Sherkin | November 16, 2015

Lower West Side Studio Loses A Dear Friend

I am deeply saddened to write that our beloved friend and family member Baxter has passed away.  Baxter was our Doberman Pinscher.  He was not only a part of our family but also a part of our studio.

Baxter was our third Dobe as my wife, son and I love the breed.  Unfortunately Dobes are known as The Heartbreak Breed because they have a ten year life expectancy.  This is not uncommon in larger breed dogs.  Contrary to their imposing appearance and all the negative press they were given throughout the 1970s Doberman Pinschers are a gentle, highly intelligent and loving breed.  Our first two Dobes, Zaphod and Tricia grew up with our son who was four years old when we first got them. Actually Zaphod came first and Tricia joined the family five years later.  After Tricia’s passing in 2005 we visited a wonderful Doberman breeder in Schomberg, Ontario named Angela.  We learned a great deal of the importance of a proper breeding facility through Z and T who came from much lesser quality breeders.  Nonetheless we loved them so much.

Baxter was from Angela’s N Litter and was subsequently given the show name Di Ravallese’s National Treasure.  He was a wonderful boy so full of energy and intelligence.  We socialized him early and well introducing him to many adults, children and other dogs.  Baxter was a show dog in the early years and went on to become a Canadian Kennel Club Champion in 2007.

Di Ravallese's National Treasure

Baxter was a gentle soul who loved everyone and everything.  At our old home in King City Baxter would often lie on the grass in the backyard and watch birds.  Never before had we seen a dog who would lie four or five feet away from birds on the grass watching them rather than barking and chasing them.  He was a very special guy.

When we moved to our new home and I rekindled my passion for making music Baxter was right there with me.  At first when I set up our studio Baxter would come into the room while I was drumming and ‘sing’ along to the music.  He had a preference for Led Zeppelin.  Don’t ask me why… he just did.  After seeing several of my friends come by the house and play their guitars and sing Baxter became interested in the spring door stoppers behind each door in the house.  He would twang them with his paws repeatedly and bark along to the twanging.  It was his version of playing guitar and singing.  He did it so often and to so many door stoppers that we had to remove them and replace them with the type that mount high up on the hinges.  You see he was accidentally damaging the hardwood baseboards and hurting his paws.

Not wanting to stifle his musical ambitions I built him a synthesizer which we dubbed The Baxtersizer.  It consisted of an inverted plastic dog bowl mounted on a sheet of wood as well as a block of wood with a spring door stopper mounted as well.  Inside the bowl was a drum trigger.  The contraption was connected via an XLR cable to either a Roland PAD-80 drum trigger or directly to a DAW running a drum trigger VST.  With this setup the Baxtersizer could trigger a variety of sounds for Baxter to play.  I would start an arpeggio on my synthesizer and the Baxter would play his ‘lead’ and bark his vocals along to the beat. Upon seeing Baxter do this my friend and Fizzbin bandmate John pointed something spooky out;  he’s doing it on tempo!

Since building his synth each time I keyed the first note on my synthesizer Baxter would come running into the studio wanting to play his Baxtersizer.  Most times I let him play for fifteen minutes before beginning my own session.  After all… it gave his pleasure and exercised his mind and body.  Plus it was pretty cool.

Almost two years ago when the Classic Rock band I play in, Coming of Age, began to play here Baxter was right there with us.  I would tell him ahead of time that his boys were coming to play music for him and promptly at 5:30 on rehearsal nights he’d be standing by the front door waiting for the guys to show up so he could greet them and determine which one of them brought the pizza.  Our family spoiled Bax a bit and I would feed him some of whatever I was eating in the studio with the guys.  Bax would then survey the situation and lay outside the glass studio doors so he could watch and listen without it being too loud for his sensitive ears.  Last week we began working on an acoustic version of our set and Bax lay in the middle of the circle of musicians digging the mellow tunes.  He was such a good boy and music lover.

Early last month Bax began to really slow down and show signs of some type of illness.  We suspected it was DCM, a heart condition he had been diagnosed with a few years ago.  It was DCM but in addition to that Baxter also had Lymphoma.  We put him on a series of medication but did not opt to have any Chemotherapy or invasive Cancer treatments done.  At almost ten and a half it would have been cruel to end his life with that kind of suffering.

Earlier this year Baxter’s daughter Fiji was supposed to have a litter.  Baxter was bred twice and has thirteen children.  Unfortunately that litter was never conceived but in early September Fiji did have a litter of fine puppies.  Baxter’s grandchildren.  Nine days ago we brought home Baxter’s grandson Bogey.  Despite his poor health Baxter played with Bogey and taught him many things including (thankfully) where puppies go to the bathroom.  Bogey potty-trained in just two days.  The two of them enjoyed each other’s company lightly playing and going for short walks.  By the end that was all Baxter could manage.

When Bax’s condition declined rapidly starting last Friday night we called the Vet to our home to give Baxter peace and relief.  She did just that and we are so thankful for her help despite the massive sorrow we now feel.  Baxter’s many friends have sent kind words and condolences and we are grateful to them for their comfort in our time of grief.

Now with our fond and wonderful memories of our very special and unique friend we will raise Baxter’s grandson Bogey with all the love, attention and care that we gave to Baxter.  That’s what he would have wanted.  We miss you so much Bax and will never forget your kind nature and wonderful personality.

Baxter Enjoying A Sunny Afternoon In Happier Times

Baxter Enjoying A Sunny Afternoon In Happier Times

Posted by: Rich Sherkin | November 3, 2015

Modular in the Lower West Side with

When I was a young boy back in the ’70s I happened to catch a late-night showing of Brian De Palma’s campy horror movie The Phantom of The Paradise.  In the movie disfigured composer Winslow Leach is taken in by his tormentor, renowned record producer Swan, and tricked into completing the musical score for a rock opera.  Leach looses his voice in an accident and Swan hooks him up to a vast array of synthesizers to allow him to sing so that he might complete his work.  This synthesizer turned out to be the legendary TONTO synthesizer.  TONTO is a synthesizer built by Malcolm Cecil and Robert Margouleff and stands for The Original New Timbral Orchestra.

Phantom and TONTO

At the time I knew none of the synthesizer’s history.  I only knew that one day I wanted a musical machine with knobs, dial and cables just like it!

At the time I was about 12 years old and already playing drums.  Still, I enjoyed visiting music stores and playing around with the synthesizers of the day.  These were legendary synthesizers by Moog, Korg, Arp and others.  I had taken piano for several years and could make some very cool sounds with them.  One day, I decided, I would have a room filled with synthesizers the likes of the machine I saw The Phantom playing.

Flash forward 39 years…


After a long career in Information Technology (so long that it was called Data Processing when I began) I built a home studio and populated it with instruments I had only dreamed of owning as a youth.  While I have a collection of percussion and stringed instruments it is my keyboards that I think I love the most.  If you’ve followed this site you may have read about the Yamaha DX-7 II, Yamaha Motif XF6 and even the Moog Sub 37 I’ve added to my collection over the past few years.  All these machines are wonderful and have their own unique character.  The Moog in particular with its meaty analog sound.  Still, none of them have the wild look and feel of a modular synthesizer.  More importantly none of them have the limitless patchability offered by modular synthesizers.

Earlier this year I began my venture into the modular world by building a PAiA 9700 modular synthesizer.  The building experience was quite awesome and being rewarded with a very cool musical instrument at the end of my journey was wonderful!  The 9700 is a great entry level synth for learning the ropes of modulars and it has taught me many things.  I’m very happy with it.

Wanting to move to the next level I had to decide whether I wanted to expand the PAiA with more modules or veer off in a different direction.  The PAiA uses a form factor known as Frac which is 4U or 5.25″ tall.  The more popular EuroRack format is a bit smaller at about 3U or 5″.  Still my heart yearned for the wall of synthesizers that I had seen as a kid.  I learned that those modules were of the larger format known as Moog Units or MU.  This was because many of the modules in TONTO were made by Moog.  MU is 5U or 8.75″ tall.  Perfect!

I then began research into MU form factor modular manufacturers.  While I would love a Moog Modular they are extremely expensive.  I discovered that a company called was making MU sized modules and they were doing it in a manner which closely replicated the actual Moog components.  I also discovered that (or DotCom) synthesizers were very highly regarded and widely used by professional and non-professional modular synth players.

It was at that point I decided to make the DotCom synthesizer the foundation of my modular synthesizer project.  The modules and cabinetry are all hand made in Texas and the quality is absolutely incredible!  Using their free application SynthInvent I was able to piece together a starter system which would get me on my way to building the wall of synths I desired.  I started with a basic 22U wide oak cabinet.  After choosing a power supply I then added 2 Q106 Oscillators, 2 Q109 Envelope Generators, a Q107 Voltage Controlled State Variable Filter and a Q108 Voltage Controlled Amplifier.  These are the core elements which make up most analog synthesizers, modular or otherwise.  I also added a Q174 MIDI Interface to connect my keyboard and the Q175 MIDI Interface Aid.  This latter provides extra MIDI interfaces, an arpeggiator and a glide feature.  To round off the initial system I included a Q110 Noise Source and a Q124 Multiples module.  The Q124 is like a one-to-many splitter which allows one signal to reach multiple modules.  I filled in the blank spaces in the panel with a Q134 Octal Blank panel.  This wasn’t the best choice for a space filler as I learned later but not a fatal mistake.

The Modular atop the Moog Sub 37

The Modular atop the Moog Sub 37

This, at last, was the start of my journey into the large-format modular world!  Since my initial purchase I added the Q115 Spring Reverb.  Because it is an analog reverb the unit incorporates a reverb tank with 3 springs.  The tank mounts inside the case and it was very easy to do.

I’ve also started building some modules by Oakley Sound Systems in the UK.  These are DIY modules and they are very good quality.  The only problem I encountered (aside from a glitch or two due to errors on my part) are that the supplied panel drawings are MOTM style and don’t quite fit into the DotCom cabinet.  I am presently working on a work-around which I will post about later on.  The modules I am have built are the 4014 Ring Modulator and the Dual LFO.

The sounds I get from the DotCom synth are amazing.  The Oscillators provide a full, rich tone with deep lows that rival even my Sub 37.  The VCF is very flexible and really makes the sound incredible.  I am experimenting with the various optional patches I can make using the gear that I have.

I am also interfacing the PAiA 9700 with the DotCom and vice versa.  I have got sounds out of the PAiA that I never thought possible and altering the DotCom’s control voltages with output from the 9700 has yielded some amazing results.  I intend to expand both synthesizers and see what I can come up with.

Modular synthesizers are very different from standard synths which feature presets.  Once I get a sound on my Sub 37 I can store it, move on and then recall the exact same sound I originally programmed.  With the modulars even if I set the patch cables the same and the knobs in the same positions the sound produced is not always exactly the same as what I first patched.  Close and sometimes the same but not always.  For this reason I have begun to record samples of the patches I make which I can then either program into my Yamaha Motif XF6 or incorporate into tracks in my DAW.  I can even alter them in the DAW and then store them as samples.  The possibilities are limitless.

I also plan to get the Q118 Instrument Interface so I can patch in guitar, bass, vocal and other sounds which I can then mash up with the modular’s components.  Anything imaginable is possible with these units.  It’s a truly amazing technology for something that was invented back in the 1960s.  The fact that we still use it today says something about its longevity.

I only wish I bought more patch cords : )

Posted by: Rich Sherkin | October 19, 2015

Oakley In The Lower West Side

Recap;  Earlier this year I built a PAiA 9700 modular synthesizer.  What a fantastic toy.  Even with only a few modules I am able to generate some very cool sounds.  Further, the 9700 interfaces well to my Moog Sub 37’s Control Voltage (CV) jacks allowing it to modulate features of the Sub 37 to create even cooler sounds.  I’ve also played with outputting audio from the 9700 to be modulated and twisted by the Sub 37.  This has yielded some very interesting results.  These will be out soon on a recording my band Fizzbin will be releasing soon on SoundCloud.

Modular synthesis has always fascinated me as have synthesizers in general.  As a youngster I first saw a massive modular in the movie The Phantom of The Paradise.  That modular was Tonto and although it wasn’t showcased in the movie I was intrigued by all the panels with their knobs, switches and ports.

After building the 9700 I began to seriously look at the modular synthesizer scene.  I discovered that for the most part the scene was common across the board except for formats.  I’m not going to get into East Coast versus West Coast philosophy here although that is another variation of the formats.  The size of the panels themselves is the big differentiating factor.  Power supplies are another main difference.  If you’re interested in learning details about modular synthesizers I highly recommend the documentary I Dream of Wires.  It’s available on Netflix.

The 9700 and other PAiA modules use a size called Frac (5.25″ tall or 3U).  One of the most popular sizes of modules now is the EuroRack (5.06″ tall or close to 3U).  These modules are easily mounted in portable cases making them ideal for schlepping around to live performances without too much effort.  The modules that most caught my attention, however, are sized in MU or  Moog Units (8.75″ or 5U).

While MU modulars can definitely be made portable they are more often seen in studio based cabinets.  The MU factor gives the modules more space on which to mount nice big knobs which are easily manipulated.  They also permit more clear labels and less cramming of controls.  These are, of course, my personal opinions and the primary reason I like the format.

Having said all this I set out in search for an MU style platform from which to launch my modular synthesizer project.  In a perfect world I’d purchase a Moog Modular system, however, it’s 5 figures just to get into that game so I searched for an alternative.  That’s when I discovered  DotCom (as they are known) systems are designed with a very Moogy flavour not only in looks but also in sound.  They are made in Texas by hand.  Many DotCom modules are available and you can mix, max and expand as you require.  My initial system consists of a 22U rack (width), power components, MIDI to CV interface,  2 oscillators, 2 envelope generates, a noise source, multi-port patch panel, voltage controlled amplifier, voltage controlled filter and reverb.  A nice start.

So what about this Oakley business?!?!

I still love the DIY aspect of synthesizers and because of this I was looking for a way to build my own modules for use in my new DotCom unit.  I should mention that as I write this my DotCom synth is in transit and I have not even seen it yet.  Oakley Sound Systems is a manufacturer in the UK which produces a wide variety of PCBs which you can build yourself.  They not only provide the boards and select components for them but also excellent documentation and design specifications for panels.  These panels are available in a variety of sizes so the same board may be used in different format synthesizers.  Not only are the boards very reasonably priced they are excellent quality and very well supported.

I started off by purchasing two boards;  The 4014 Ring Modulator and the Dual LFO board.  I have completed the 4014 at this time.  This board is based on the ARP4014 Ring Modular used in the ARP 2500 and 2600 modular synthesizers.  These modulars were ground-breaking in the 1970s and I felt that using some of their components in my modular would make for some awesome sounds.

The build went very smoothly because as I mentioned, the documentation is excellent!  It would have  been finished a day early if I would have paid closer attention to my parts order and not ordered an incorrect part.  No harm done though.  I can’t plug the unit in to test until I receive a bench power supply that I ordered from  I don’t intend to plug any home-built modules into the actual synthesizer’s power supply until I’ve confirmed they’re working ok in a closed environment.  That’s a holdover method I used as a software developer and network engineer for 30 years and it’s as wise today as it was way back when.

More to come when I build the LFO and especially when my DotCom unit arrives.  Until then, here are some pictures of the 4014 Ring Modulator build…

Beautifully laid out board with easy to read labels

Beautifully laid out board with easy to read labels – Note how the labels are beside the components so you can still read them once the components are installed.  Makes for easy debugging!

Almost populated - Saving the ICs for last

Almost populated – Saving the ICs for last – The board supports multiple power options for use in different manufacturer’s modulars.

Completed the soldering - Time to mount to the panel

Completed the soldering – Time to mount to the panel

Mounted to the front panel

Mounted to the front panel

Completed 4014 Ring Modulator

Completed RM-4014 Ring Modulator

Posted by: Rich Sherkin | August 27, 2015

Two Day Grinder

Last weekend was very exciting for Coming of Age the Classic Rock band I’m in.  We played three shows in two days, Friday night, Saturday Morning then Saturday night.  While exhausting it was a lot of fun.

Saturday’s show was at the Copper Kettle Festival put on by Creemore Springs Brewery in Creemore, Ontario.  Several live bands played including Coming of Age and the Progressive Rock band our Rhythm Guitarist / Vocalist Johnny G. fronts with Lead Vocals, Altered Fate.  While I’ve heard some of Altered Fate tunes on John’s iPhone it was my first opportunity to hear them play live.  Wow are they awesome!

I managed to get some video of Altered Fate and was happy to learn that Rick Z. the guitarist from a band I previously played in called Highway 26 had filmed some of our show.

Here for your viewing pleasure are a couple of those clips…

Posted by: Rich Sherkin | August 21, 2015

August 21st – Weekend of Classic Rock

Coming of Age will be performing this weekend from Thornbury down to Aurora giving everyone a chance to enjoy some awesome Classic Rock music!  Check out one of our shows!

CoA – Pipers Sports Bar & Grill – Thornbury

CoA at The Copper Kettle Festival - Creemore

CoA at The Copper Kettle Festival – Creemore

CoA at Aw Shucks in Aurora

CoA at Aw Shucks – Aurora

Posted by: Rich Sherkin | August 19, 2015

Hohner B2A – Active Electronics Repair

A couple of years ago I purchased a used Hohner B2A Headless Bass.  I love playing it!  It’s light.  It’s unique looking.  It wasn’t too expensive.  And it has Steinberger hardware.  It also has active electronics.

At some point during my playing it the active electronics failed.  That is to say that when the bass was plugged into a guitar cable and the switch was turned on the LED did not light nor did the extra volume kick in.  I replaced the battery and made sure the contacts were clean but still no dice.  The bass still operated fine with the active electronics switch turned off, however, the fact that it wasn’t fully functional bothered me.

I decided I would try to diagnose and repair the problem.  I didn’t think the problem would go too deep unless there was some type of component failure in the active electronics themselves.  Fortunately I was correct.  The first thing I did was to ensure I had details on the wiring of the bass.  Through some searching on the Internet I was able to come up with the following diagrams.  Each was discovered through forums and I never found the original poster but whoever you are; thank you!

B2A Schematic

B2A Schematic

Switch Wiring

Switch Wiring

Circuit Board Connections

Circuit Board Connections

Starting at the beginning of the electronics chain I checked the power connection to the battery compartment.  There are two metal contacts inside the battery compartment and I suspected they may not be making contact with the battery properly.  As it turned out I was correct in this assumption.  To test my theory I connected a pair of alligator connectors (the greatest electronics debugging tool) to the leads connected to the battery compartment and tested them with a multimeter.  Bingo!  No juice was getting through to the electronics.  This, of course, would definitely have an effect on the rest of the circuitry.


Once I determined that the power wasn’t getting out to the electronics from the battery compartment I tested the theory by wiring a battery directly to the power leads using alligator clips.


This setup made the active electronics work.  Remember that if you want to test the electronics you must have a 1/4″ guitar plug inserted into the bass otherwise the electronics will never turn on.

At this point I used some contact cleaner to clean off the battery connection points inside the compartment and I gently bent the metal contacts outward so they would be sure to make contact with the battery terminals.  This worked out perfectly and the bass’ electronics were active once more.

Having the bass on the bench already I decided to have a look inside the main compartment to ensure everything was ok.  Older gear is susceptible to solder joints coming loose over time and I was experiencing a glitch with the electronics volume control.

The B2A Electronics Well

Close inspection revealed that the solder joint on one wire leading to the potentiometer and come loose.  That would explain the intermittent problem.

Note the green wire has no solder holding it in place

A quick soldering touch up and the wire held firmly in place.  Remember when soldering to clear away any wires (gently) to ensure the shielding does not get melted by the shaft of the soldering iron.

I cleaned up the main compartment (it had dust in it) ,sealed up the electronics compartments, gave the bass a polish and presto – new life for an old bass.  I really love this instrument – it’s so much fun to play!

Posted by: Rich Sherkin | August 6, 2015

ESI-2000 Upgrade – Part 2: The Hard Drive

It’s been a while since I performed the floppy disk upgrade to my ESI-2000 sampler.  As I mentioned in the earlier article the USB floppy drive still partitioned itself out as 1.44MB disks.  This caused really inconvenient load times as the unit had to be babysat.  Enter the hard drive.

Finding a hard drive on the EMU’s compatibility list proved a bit of a challenge.  SCSI drives from the mid to late ’90s are hard to come by these days.  Even the cables are long out of fashion.  Still, that’s where Kijiji comes in handy.  I posted the EMU’s drive compatibility list on Kijiji requesting anyone having a drive that matched get in touch with me.  As it happens I met up with this excellent fellow named Frank.  Not only did Frank have a drive I needed, the Quantum VP32210, he drove it up to my remote location to deliver it.  Not only that he also brought a second drive to use as a spare.  This worked out especially well as the Quantum drive didn’t quite pass the EMU’s format procedure – but more on that later.

As a Computer Guy from the early ’80s I have acquired a pile of old cables.  Unfortunately several months ago I threw out a box full of them as I thought I’d never need them again.  Once again Frank came to the rescue sending me a 50 pin SCSI cable and a 3 way power connector.  More on this cable later too.  I have to say that if it weren’t for Frank this project wouldn’t have succeeded.  Thanks so much Frank!

The first problem I ran into was the power connector.  While the EMU had a mini-connector suitable for a floppy drive the hard drive required a standard old-style PC power connector.  Searching for the conversion cable was fruitless so I ended up making my own.  This involved snipping the end of the EMU’s connector as well as the standard connector.  Making sure I had all the wires in the right place (+5, GND, +12)  I soldered the two parts together and voila – a suitable power connector.  When doing this process I highly suggest documenting everything so you don’t run into problems later on.

IMG_5297 IMG_5298

I used shrink tubing to prevent short circuits or other nasty things from happening to the power connectors.  Don’t use electrical tape as it will ultimately come off and leave a gummy mess.

One IMPORTANT NOTE:  The power supply in the EMU is not covered.  Touch one of the capacitors and it might be the last thing you touch!

I configured the SCSI drive as device 2 and left the termination in.  I figured at this point the job would be a cakewalk.  As it turned out that wasn’t the case.  When connected to the internal SCSI connector the EMU would not even power up.  It would just make a clicking sound.  Switching device IDs, termination, etc… had no effect.  I then removed the motherboard cable to the external SCSI connector connected the internal drive to it and everything powered up fine.  I was able to perform the ESI format under the Disk menu.  The Quantum drive failed this process but the Seagate had no trouble.  The only problem was how to get the samples off the CD-ROM and onto the hard drive with only one connector and no daisy-chain SCSI setup.

As it turned out that wasn’t too much of a problem.  The ESI-2000 allowed me to hot-swap the cables.  In between swaps I would use the Disk menu’s Mount Drive option to rescan the SCSI bus.  First I’d connect the CD-ROM and load a sample bank.  Then I’d switch to the cable for the internal drive, rescan the bus and save the sample bank.  Again, writing things down as I went saved a pile of headaches.  While not a perfect solution it allowed me to transfer all my samples to the hard drive, disconnect the external SCSI cable and leave the internal drive hooked up.

One important note when switching the cables;  do not crank the cable up from the right or left side.  This might cause the pins to bend and weaken them.  You should also not brace your hands on the motherboard.  You could inadvertently break off a component.  Grasping the connector rather than the cable will also help you from loosening the thin SCSI connector wires from the connector itself.  These were lessons well learned from my early days in the PC business that saved me from potential problems during this upgrade.

Setup during sample transfer

Setup during sample transfer

Nicely cabled and ready to close

Nicely cabled and ready to close

So there you have it… another piece of vintage synthesizer gear updated to play another day!

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