New Euro to Buchla CV Translator - CV1.2

The CV1.2, one of the cvgtElements range of DIY circuits, is available and its data pack is ready to view/download on the support page. CV1.2 is ready built and tested, you have to DIY them into your own modules/panels.

CV1.2 takes a Euro 1V/octave CV and translates it into a Buchla 1.2V/octave CV - ideal if you want to take a Euro pitch CV into the Music Easel's pitch KEYBOARD CONNECTION

The GTPulse datapack is also available to view/download on the support page.

Custom Half-width Buchla Modules

I was asked to design and build a pair of custom half-width Buchla modules for some clients. They each had two half-width slots spare in their custom built cases and wanted to fill the spaces with Euro to Buchla CV and gate translator modules.


The brief was simple (and the same for both clients): 5 channels of 1V/oct to 1.2V/oct CV translation and 5 channels of gate boosting to Buchla levels; the Buchla stepped pulse was not required, just big pulses (10V or more).

This was a great opportunity to use the Synovatron Proto range of prototyping boards which accomodate 5 channels and offer stackability if more circuitry is required than will fit on one board; see below.

The Proto range of boards

As the Proto boards are designed primarily for Euro there was space on the 4U Buchla front panels to add some extras in the form of a passive attenuator. Here are the front panel designs that we agreed on:-

CV and Gate modules

To keep costs down it was decided not to have panel marking as the functions are obvious.

The CV module design used a straightforward precision amplifier with gain of 1.2000 (yes that accurate), 1M Ohm input and 0 Ohm output impedances. The gate module used comparators and output and LED drivers. The outputs each have diodes in series allowing them to be wire-ORed by just connecting outputs together (common to Buchla, wish it was used on Euro).

The CV module electronics fitted nicely on a ProtoJax board with plenty of space as you can see:-

For the gate module I decided to put the input comparators and sockets on the ProtoJax board and output buffers and LEDs on the ProtoXp board and stack them together (it  probably could all have been put on one board but it was simpler to make use of the space). The stacked ProtoJax and ProtoXp boards can be seen here:-

The gate board was powered from an MTA connector and the CV board took its power from the gate module (hence the 10-pin ribbon headers for a linking ribbon cable); this was at the client's request as they only had one spare connector (these are very low current modules and daisy chaining them didn't cause any crosstalk issues). 

The finished panels looked pretty good; they were made by Schaeffer using Front Panel Designer http://www.schaeffer-ag.de/en/front_panel_designer/the_idea/.

  
If you are interested in the Proto range of PCBs or in having a custom module built then please contact me at synovatron@btinternet.com

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. 

SchneidersLaden have stock of 5ASM2DB which can be ordered from their website at http://www.schneidersladen.de/en/manufacturer/synovatron.html.

For DIY enthusiasts it is also available as a kit or as a bare PCB direct from Synovatron (please email synovatron@btinternet.com). 

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

5ASM2DB Adaptor/Expander

5ASM2DB DIY Kit

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!

Eurorack DIY Prototyping Cards Rethink

Post updated 3rd July 2018

The Synovatron Eurorack DIY Kits have now been discontinued. Because many of the kit components are easily available from online retailers it made sense that Synovatron just provides the unique (e.g. PCBs) and harder to source parts (e.g. pot brackets). This provided a great opportunity to reassess the PCB designs 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 stack-up:

ProtoJax, ProtoPotz and ProtoXp boards stacked together

Examples of headers and sockets used to stack the boards

ProtoPotz

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.

ProtoPotz pot breadboard PCB

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

ProtoJax

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 makes it more advanced than DIY2 and DIY3 pcbs?

• Larger breadboarding area. 
• Supports the A-100 bus similar to ProtoPotz.

ProtoJax jack breadboard PCB

ProtoXp

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 expansion breadboard PCB

DIY2 jack breadboard PCB

 

DIY3 jack breadboard PCB

Eurorack synth prototyping products now available

Please check out the product and support pages on this blog. 

Kits and cables are also available through eBay; just search "Modular synth prototyping kit" or click here

Update on New Eurorack modular synth prototyping kits - Circuit boards have arrived

The new DIY prototyping circuit boards have arrived. They look good and the quality is very good.

The pots, pot brackets, headers, caps and jacks all fit which which is a huge relief.  To give you an idea of what they'll look like assembled checkout the preliminary piccies below of both types of board with some components assembled ready for prototyping to start. Note I have added some LEDS to one of the DIY2 boards too.

Time now to sort out the packaging, data pack, options and pricing - about another week before they become available.

Update on front panel artworks

Just thought I'd give a little more detail on front panel artworks as there is already some interest.

The picture below of my module currently in development shows the CAD drawing for a 12HP front panel in the top left. The adjacent front panel overlays show an evolution from a very simple, flat looking artwork to more 'sexy' metallic looking and coloured alternatives with some apparent depth.

 
Edit 08/07/11: The following graphics, based on ink-jet/laser printable vinyl overlays, was attempted on the first off batch of CV Tools modules but has been withdrawn in favour of a standard screen printed panel for two reasons. The first was that it was not liked that much by customers; people saw it as a cheap label. The second was that it was expensive and difficult to apply accurately. I will still use the overlays for prototypes.Please read the following but note it has all been superceded by events.

My task is to make this a service that is affordable by streamlining how I go about setting out the pot scaling, legends, functional grouping (separating lines or boxes). A good place to start from is if you use Schaeffer Front Panel Designer to get the panel made then I can use the DXF file generated to align the graphics to the holes; obviously with as much description from you as possible about what you actually want to see.

The one-off 2mm anodised panel from Schaeffer cost me 27 Euros (about 23GBP, $35US but it is beautifully machined!!); I anticipate the cost of an artworked plastic overlay would need to be less for that size panel to make it attractive, including my design effort (that's why I need to streamline the process - the slicker I get the more viable it'll be!).

The hardest part is lining up the overlay accurately on the panel as the overlay is self-adhesive. I'm getting quite adept at this now as I have prototyped several overlay types. You do get several chances and I may include a spare.

I am still developing the technology as it needs to have great graphics, be cheap to make whilst still having good wear and scratch resistance properties.  This balance is not easy and I will still need to explore better processes and techniques so initially this will be for smaller prototypes with some caviats on how much abuse it can handle. The artwork is great quality though and the durability is reasonable but could be better. The price will reflect this fact. Having said all that I'm going to use it in my system as it stands as I don't tend to abuse my hardware.

Any suggestions and comments would be most welcome.

New Eurorack modular synth prototyping kits preview

Hello fellow synth fans,

In the next few weeks I will be producing a range of Eurorack standard modular synth prototyping kits for synth constructors and enthusiasts; these kits will comprise Doepfer compatible printed circuit boards (PCBs) and components. 

These  will enable you to make neat prototype or one-off projects that accomodate bracketed pots, PCB mounted jacks, switches and LEDS so that they can be easily mounted to a module front panel.

The idea is that you build your designs on the breadboards supplied and get the front panel manufactured separately, either by yourself, or by a company such as Schaeffer http://www.schaeffer-ag.de/en (I can provide some template files that you can use directly or can modify as you require. I will also look at providing some standard panels e.g. five pots and five jacks but this is still being costed; more on this in the coming weeks).

I will also be able to provide you with a relatively low cost high quality front panel overlay to give your module a professional appearance; this service will also be explained in more depth in the coming weeks.

This is an overlay I made for a product in development
(this is the next product - a versatile voltage processor)

There will be 3 kits available:


Kit 1: This comprises 2 single-sided prototyping matrix-type breadboards and cable as follows:-

• DIY1. This PCB is primarily for mounting control pots and prototyping most of the circuitry on a breadboarding area.  It is provided with 5 control pots and mounting brackets; the pot values supplied are 50k linear (type B) but you can request 10k, 100k linears (type B) or 1M log (type A); 2 100nF decoupling capacitors and a 16-pin header are supplied fitted to the board; the pots and brackets are supplied loose. Not all pots need to be fitted and there is provision for PCB mounting of LEDS. The PCB has +12V, -12V and 0V busses.

• DIY2. This PCB is primarily for mounting jack sockets but switches (Taiway series 200 sub-min toggle switches) and LEDS can also be fitted.  It has a smaller breadboarding area than DIY 1. It is provided with 5  3.5mm jack sockets but some can be left out to fit switches or LEDs.

• Doepfer compatible ribbon cable.

• Data sheet.

Kit 2: This comprises just the DIY 1 breadboard and five pots and brackets.


Kit 3: This comprises just the DIY 2 breadboard and five jack sockets.

A range of components such as pots, brackets, knobs, jacks and cables will also be available.

This is just a preview and I will put up more details, costs and photos in the coming weeks.