Sunday, May 12, 2013

Modular Analogue Synth Doepfer DIY Little Dieter Build

In researching modular synths and looking for a way into building my own I found the Doepfer DIY circuit board. The board provides a number of basic building block modules for a reasonable price. It is a DIY board however and it's intended the end user will come up with a panel or/ and case.

After putting together my Shruthi-1 I found this thread on the Mutable Instruments forum on a kit called the Little Dieter that was put together by a guy called Frank. You can check out his webpage here and his Flickr page here which also has instructions for putting the Little Dieter together. It provides a panel in eurorack standard and all switches, pots, LEDs, mechanical bits, resistors, knobs for the pots and connecting socketed wirey bits.

A Doepfer DIY board and the Little Dieter seems like a good way to go so I went ahead and bought a kit.

And here it is!

The blank panel. Beginning to put in pots....
Rear side of the almost fully stuffed board of pots and jacks.

 Front panel with pots and jacks installed ... Also visible the Doepfer DIY board.
 The slow and tedious task of soldering hundreds of point-to-point connections. Here are the beginnings of the ground wiring. I used a combination of wire going from point to point. Also in some other places I experimented with using some wire without a coating to make the connections.
 Continuing with ground wiring. I put some heat-shrink wrap on some of the leads of the LEDs.
 Further wiring...

And completed with knobs attached.

No power supply yet so I am yet to test it.

Thursday, May 9, 2013

Analogue Synth Panel DIY

I have been playing with and learning to work with sheet aluminium recently to make some panels for my modular synth project. I used 2mm aluminium because this is what is used in the Doepfer panels. I got out the ol' paper CAD to sketch out some ideas. The plan is to make a converter to go from 1/8th to 1/4 inch jacks and visa-verse. I mocked up a prototype on cardboard to see if the sockets would fit together on the back. I took height and width dimensions from the Doepfer a100 construction details page to make the panel conform to the eurorack standard.


And then I set about hacking into my sheet to make the panel. Here it is:

 ... and where it could fit in my rack:

The cut was not perfect. There is an art to cutting a straight line with a hack-saw I found. I cut to one side of a scored line to continually reference where the cut should be. Of course it would be easier with a workshop full of pro tools but we shall see how this goes!

I had a brief play also with hand drilling some holes for the sockets but there were off by several millimeters. I'll continue to try and get a better result, failing that I may have to get access to a drill press.

I have been thinking also about how to apply labels to the metal surface and have a few ideas I will play with.

Shruthi-1 Synthesiser Build

I put together a Shruthi-1 kit in a few evenings. It's a nice little synth with a digital oscillator and an analogue filter. Web page for the Shruthi-1 is here.

(nearing completion)

The kit does not come with an AC adapter. Not all adapters are created equal I found out! The circuit requires a voltage within a specific range. No problems here but it turns out the markings on an adapter can specify not what is being output but that the adapter will output at least this amount. Measuring the output of an adapter labeled as 9V gave me 14 volts for example. Something to be aware of! Link to some further info on AC adapters here.

and here she is in her natural habitat...

Wednesday, May 1, 2013

DIY Patch Bay

Some time ago I made my own 1/4 inch jack patch-bay. The wood was in its previous life floor-boards. The metal was an L shaped piece of roof gutter that was hammered flat. I did not know at the time about normalling any of the connections, so cords need to be connected in the front for any connections to be made. At least this way it is easy to visually see what is connected to what. Most of the materials were scavenged and the only thing I bought were cheap 1/4 inch jacks that half fall apart (you can see were one of the small rings has just fallen off) and some wood screws. The thing is quite heavy. Total build cost was less than $10. Dymo tape for labels. Some of the holes are spaced a bit wonkey but it adds to the character I guess. :-P