I'm new to this forum, a proud model D owner usually up to my armpits in one synth's guts or another. I thought my latest project might interest at least some Moog fans following Ken Elhardt's footsteps...
I've spent the last three days rehousing and wiring up an original Formant Resonator pcb rescued from a scrapped Polymoog. This has been done before but I decided to go a few extra miles and rescue the 8 preset formant filters as well as the triple resonator.
This involved building a suitable power supply to generate +15V, -15V and 5V DC and something to drive the 3 to 8 decoder to select the fixed formant modes. I followed the belt and braces route in the end and built up a wafer switch that counted in binary from 0 to 7!
I cut down the remains of the front panel leaving just the resonator controls and built a wooden box to house it and the pcb. I then built the power supply into the rear of the cabinet.
The output of the fixed formant circuits was not buffered so I retasked one of the now unused op amps to act as an output buffer. The two sections are being fed with the same output but end up on different outputs. I fitted a bypass switch and the 8 way fixed formant mode switch to the rear panel.
After three days of toil I powered it up and it didn't do anything useful... just lots of put put put put put noises...
Then I discovered that a wire had fallen off one of the front panel sliders and hey presto the whole thing jumped into action....
Even the fixed formants worked... well 7 of them... one of them was making perculiar noises and I suspect I ended up fixing a fault that the Polymoog had before it was scrapped! One replacement op amp later and 100% functionality.
There is some noise I need to tackle - mainly due to cable routing.
Here is a quick demo:
Firstly a drone sound made whilst moving the front panel controls fed from a JUNO-106. Then some strings from the SY77.... which are turned into a choir by the resonator! Then a brass patch on the Minimoog made a little more brass like, then a nylon guitar made with the Minimoog and the resonator, then a series of formants using a JUNO-106 as the source.
Download Here:
http://www.sendspace.com/file/usxcdn
It needs a little more experimentation but definitely an interesting piece of kit.
It's worth pointing out to all that may be thinking a Polymoog was destroyed in the process of making this resonator that she was simply far too far gone and has been a great source of parts for other's treasured beasts. In fact the irony is that after all my toil I ended up having to repair a fault on one of the formant circuits that I strongly suspect was present prior to the synth being parted out
