Modifications by Mike Walters, 2005
Sound Samples on Bottom of Page
For years, I wanted to have the rhythm/auto-accompanyment you find on old living room organs, but in a portable package that wouldn't take up much space. I did some research, but there didn't seem to be anything like this that existed. I even thought about buying an old Lowery or Thomas or Conn, etc, to strip out its rhythm circuits and low octave of the keyboard and recase it. I asked a year or so later on the combo-organ list, and a fellow in the UK named John Brewer told me about The Elka Wilgamat, a quite obscure Italian rhythm box from the Seventies. This sounded exactly what I was looking for! So I typed in"Wilgamat" on ebay, and nothin. I looked at some completed auctions, and there was a broken Wilgamat that tried to sell three times and no bites!! Long story short, I bought this non-working Wilgamat III dirt cheap. Looking back, I see how lucky I was to find this one. These things are super rare. Even on Google. Not that there's much demand for the Wilgamat.
The first thing I had to do was to get it working. It lit up, but no sound. Unfortunately, I never had any schematics for the III. Turned out the magic fix was sending minus 12V to ground. Fixed. Basically the Wilgamat works as follows: It's an analog sound generated, non-programmable drum machine with the option of connecting an auxiliary Elka organ to activate the chord and bass sequences, via an interface on the back. This works by sending -12V to a bus, and each pin of the interface goes to 24 notes on the keyboard. Short the A pin, the C pin, and the E pin with -12V, and the Wilgamat plays a sequence of bass, piano, brass in the key of C major. It also has an arpeggiator. The bass and arpeggiator can play 2 different sequences with each rhythm (Waltz, Rock 'N'Boogie, Disco, Bossa Nova, Cha-Cha, etc).
The keyboard I used came from an extra junked Casio CT-310 I had lying around for parts. I used the existing octopus strip key contacts, but rerouted the switch matrix by cutting traces, bridging, etc. Ultimately, each key bridges a common bus where I sent -12V. I hardwired the back of the keyboard interface inside the Wilgamat to a 25 pin parallel cable from an old computer component. This is so I can undo the keyboard if I needed, though it's meant to be permanent and it's hidden inside the cabinet.
The cabinet is built from oak, and stained cherry. The cool thing I did was route each sound individually from the auto-accomp section to their own 1/4" outputs with an on/off switch. This allows me to patch and process sounds separately. For example, I can send the arpeggiator to a delay pedal, the brass to a flanger, and run 1/2 of the rhythm through a synthesizer's filter. On the the interface with these outputs, the functions are mostly labeled in Italian (Ritmo, Tromba...) in tribute to its origin. One if these functions is titled "Synthi" which is a source of audio I found on the bass circuit. It's routed to a 4 position rotary switch, and plays the bass sequence in 4 selectable octaves of square wave leads.