Saturday, 13 September 2014

5 into 1 Analogue Systems to Doepfer Bus Adaptor/Expander

The new 5ASM2DB Analogue Systems Module to Doepfer A-100 Bus Adaptor/Expander is now in stock and available to order. 

For DIY enthusiasts it is also available as a kit or as a bare PCB. 

The 5ASM2DB offers five Analogue Systems sockets on one small circuit board with low-current LED indicators to show that ±12V and +5V power is available. It comes with a ribbon cable to connect to the A-100 bus and four self-adhesive nylon PCB mounting pillars (you can of course use screwed in pillars so a drilling template will be provided).

If you have several Analogue Systems modules in a Euro rack then the 5ASM2DB could be a better alternative to using several ASM2DB Adaptors because it expands the bus and frees up A-100 Bus connectors for Euro modules; it costs roughly the same as three ASM2DB Adaptors. ASM2DB and DM2ASB Adaptors are still available.

5ASM2DB Adaptor/Expander
What you get with the 5ASM2DB Adaptor/Expander
What you get if you order the 5ASM2DB DIY Kit

Price info and ordering

For sales, support and combined shipping enquiries please contact  

The base price is without delivery and VAT.
The UK and EU prices include delivery and VAT @ 20%
The ROW price only includes delivery; VAT is not applicable. 
Model                                        Base            UK              EU                ROW
5ASM2DB Adaptor/Expander    23.00 GBP   30.06 GBP   32.58 GBP   27.45 GBP
5ASM2DB DIY Kit                      16.00 GBP   21.66 GBP   24.18 GBP   20.45 GBP
5ASM2DB Bare PCB                   (please enquire at
UK delivery by Royal Mail First Class; elsewhere by Royal Mail International Standard.

Friday, 29 August 2014

New product preview

This is a design that has been hanging around for over a year in a 95% complete state but I have now taken the bold step of finishing it and going into production. It is called the 5ASM2DB and is a 5 socket version of the popular ASM2DB Analogue Systems module to Doepfer bus Adaptor. It is fabricated on a small circuit board and has 3 LEDs that indicate the presence of ±12V and +5V. The 5ASM2DB will be supplied with 4 self-adhesive nylon mounting pillars and a short ribbon cable so it can be placed adjacent to a busboard and linked via the ribbon cable (standard Euro rack 16 pin cable). It is not recommended for use with the Analogue Systems RS-370 as this draws a whoppng 680mA from the 5V rail.

It will be priced at roughly that of 3 ASM2DB Adaptors so the aim is you get 5 for the price of 3; which will be of interest to those of you with many Analogue Systems modules to go in a Eurorack case.

Availability is from mid-September and will also be available as a DIY kit and as a bare PCB for the more adventurous DIYers. Here's an image from the CAD package - it will not be red BTW!

Confused by Cwejman ribbon cables?

I received an order to build some Cwejman standard ribbon cables that were 40cm long. Up until then I had no idea they were different to standard Eurorack cables. So here is what I found out and hopefully this takes the mystery out of it for anyone who is lucky enough to own one of these top modules (and it's also a sales plug - no pun intended).

Saturday, 12 July 2014

Eurorack DIY Prototyping Cards Rethink

The Eurorack DIY Kits have been quite successful and when the last DIY1 PCB was sold several weeks ago it provided a great opportunity to reassess the PCB design rather than just reorder more of the same.

What has emerged is a revised and rebranded Eurorack prototyping solution that is more usable and more elegant than before. The revised product revolves around three PCBs in the Synovatron Proto series: ProtoPotz, ProtoJax and ProtoXp

The new Proto PCBs' holes line up with each other to allow each board to be stacked one on the other using header plugs and sockets; allowing power and signals to be routed between boards without resorting to linking ribbon cables. Here is an example board stackup; this all fits neatly behind the Synovatron 8HPJ front panel (8HP wide with pot and jack holes):-

ProtoJax, ProtoPotz and ProtoXp boards stacked together

Examples of headers and sockets used to stack the boards


ProtoPotz is the direct replacement for DIY1 PCB (as used in DIY Kit 1 and DIY Kit 2). It is designed to hold up to five 16mm P160KN series pots using brackets. What's new about it?
  • Plated-through holes for robustness and convenience, essentially it's a double-sided PCB. 
  • Better supports the A-100 bus with dedicated positions for 10 or 16-way open or boxed headers, small electrolytic capacitors and protection diodes (to protect against reverse power connection.
ProtoJax boards with 5 pot brackets are available from Synovatron for 7.50GBP + delivery + VAT @ 20% (UK/EU only). ProtoJax will also be supplied in DIY Prototyping Kit 1 as a replacement for the original DIY1 PCB.

ProtoPotz pot breadboard PCB
Here is the range of pots available from Mouser that Synovatron recommends for use with ProtoPotz:-


ProtoJax is an evolution of DIY2 and DIY3 PCBs. It is designed to hold up to five Cliff CL1384 3.5mm mono jacks. It is almost identical to ProtoPotz except it has footprints for jacks instead of pots and another two rows of breadboard holes. What's make it more advanced than DIY2 and DIY3 pcbs?
  • Larger breadboarding area. 
  • Supports the A-100 bus similar to ProtoPotz.
ProtoJax is available from Synovatron for 7.00GBP + delivery + VAT @ 20% (UK/EU only). It will not replace DIY2 PCB in DIY Prototyping Kits 1 or 3 except as a requested option.

ProtoJax jack breadboard PCB


ProtoXp is a completely new PCB. It is an eXpansion board designed to add more breadboarding area to ProtoPotz or ProtoJax boards. It's features are:-
  • It has a cutout that allows the A-100 bus ribbon cable connector to fit without fouling on the ProtoXp board. 
  • The same ±12V power bus structure as the ProtoPotz or ProtoJax boards.
ProtoXp is available from Synovatron for 5.00GBP + delivery + VAT @20% (UK/EU only).

ProtoXp expansion breadboard PCB

 What else?

Data sheets will be prepared for the Proto series PCBs and download links will be posted online over the coming days.

DIY2 and DIY3 boards will be available for the foreseeable future. These can be used on their own or with the Proto series boards but the PCB holes do not align exactly so a linking ribbon cable is the best way to pass power and signals around between Proto and DIY series boards. Consequently the price of DIY2 and DIY3 PCBs will be discounted while stocks last. 

Sale price for DIY2 is 3.75GBP + delivery + VAT @ 20% (UK/EU only). Was 5.00GBP.

DIY2 jack breadboard PCB

Sale price for DIY3 is 5.00GBP + delivery + VAT @ 20% (UK/EU only). Was 6.75GBP.

DIY3 jack breadboard PCB

Please contact Synovatron for order enquiries, delivery costs and quantity/combined order discounts.

Sunday, 30 March 2014

Website updates

Due to being very busy trying to keep up with orders and developing new modules this blogsite has been sadly neglected. I was thinking I'd get round to putting up a proper grown-up website but that will not happen for a while yet as it requires careful consideration; I hope to setup an e-commerce type site with a basket and checkout facility. So apologies this is long overdue - I have updated details and pricing info for DIY Kits (Prototyping Kits and CV Tools Kit). More will be added to the DIY Kits page over the coming months including front panels and PCBs that can be ordered separately. I have also updated the Adaptors page and added a CVGT1/cvgtMM page.

Saturday, 11 January 2014

cvgt MM Buchla Translator ModuleModules are now shipping

The first cvgt MM modules have started shipping to clients at the top of the pre-order list. If you want to be added to the list then please make contact on

I will build in small batches and work through the list in chronological order and will then contact you when your order is ready to ship. Only at that point will I request payment (see prices below). Please note that this does not form any contract between us and you are not in any way commiting yourself to making a purchase until such a time that you make a payment.
Initially the cvgt MM will be only available directly from me but if there is enough demand then it is possible they will become available at all the usual distributors in due course. 

The current variants are:-
  • Buchla-Euro (round or hex nuts on 3.5mm jacks; please select)
  • Buchla-Serge*
  • Buchla-BugBrand*
  • Buchla-Fenix*
*These are banana socketed variants and only the colour of the banana sockets is different (to match the target system); All are variants (inc. Euro) are to translate from Buchla to 1V/octave systems.

The User Manual is being worked on and will be ready very soon and will posted here in an update. Please checkout the Eardrill website for more info on the ModuleModule concept and other great products from Chris Muir.

The price for the cvgt MM is as follows:-
UK is 180.00GBP plus 9.00GBP delivery (prices include VAT at 20%)
EU is 180.00GBP plus 15.00GBP delivery (prices include VAT at 20%)
ROW 150.00GBP plus 13.00GBP delivery (import duties and taxes may apply).

Either one or two modules can be sent within the quoted delivery price for the UK but add 2GBP per exra module for the EU & ROW. 

It is estimated that it will take up to 2 weeks from registering on the pre-order list before your module is ready to ship and the shipping time from the point of payment could be 2 working days ( UK ) or 5 working days (EU/ROW).
Payment is by PayPal to
Bank transfer is available on request.

Euro variant
Serge variant
Euro (top), Serge (bottom)

Friday, 6 December 2013

cvgtMM - A ModuleModule version of the CVGT1

This project has kept me busy for the past few months. It was suggested some while ago that I do a ModuleModule version of CVGT1 to go in a Buchla (see my earlier post). My initial thoughts were that it was probably not the best solution as front panel space in a ModuleModule is quite restricted and Buchla real-estate is not cheap. However what I didn't consider was that Buchla can also talk to Serge, BugBrand, Fenix etc and Serge users seemed to want this solution. Consequently I set about designing (or redesigning) CVGT1 to fit in a ModuleModule form factor. Chris Muir from Eardrill produced a great interface document which defines just about all I needed to know for designing a ModuleModule (I'll refer to ModuleModule as MM from now on). 

Because of the smaller front panel space I had to lose some features i.e. scaling and offset on the Buchla to other synth CV channel but as it is in a Buchla and will interface to an external 1V/octave synth I've fixed the scaling at 0.8333 (1/1.2) and zero offset. The PCB design allows either 3.5mm jacks or 4mm bananas to be fitted; so one PCB can be configured to for Euro or Serge etc.

Clearly this design has PCBs parallel to the front panel unlike CVGT1 which has them perpendicular hence the change in jack style.  The PCBs had a completely new layout with all front panel related parts on the first board (Front Panel Interface Board) and most of the circuitry on the second (Main Board). Here are some design images of the variants (there are a few very minor tweeks to the graphic since this was drawn and you'll see a few variations in the prototype pics below).

I built a prototype and that's all working nicely. Aside from the new PCB layouts I had to make some changes to the pulse/trigger/gate circuits to run from ±15V rather than ±12V but there were no major changes. Heres a scope image of the Buchla compatible pulse I achieved:-

Here's the prototype with an ink jet printed plastic overlay on the front panel.

All components are conventional through-hole types - I may go over to surface mount if I get more orders than I can personally cope with but think I will still retain through-hole if anyone fancies a kit. You will also notice that the scaling trimmers are front-panel accessible (with a small screw driver) however these are for very fine trimming ±0.5%.

The first pre-production modules will be available in just over a week when the screen-printed panels are in stock. I have a number of interested 'customers' that I will contact soon and will start a pre-order list; please feel free to contact me to get on the list: It will be a 'no-commitment no money up front' arrangement as before with CVGT1 and I will poll all interested parties in turn when I have a module ready to ship to see if you want one. I have not finalised a price yet but guess it will be in the same ballpark as Eardrill's own range of single panel medium complexity MMs.

It will be interesting to see how this takes off, CVGT1 started slow and now there are 200 out there with bags of interest still.  I will do an update in the next week or so. Thanks for reading.