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A grounding cable has been made available as an accessory to Theremax.

In many instances, the audio output connection an amp/speaker or mixer establishes a stabilizing earth ground link with a three-prong power cord and there is no need for this cable:  The circuit-common/”ground” of Theremax isn’t floating as is the situation when going into a two-prong (or battery) powered device, but anchored to the stable, zero…

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Polyphony Magazine

Polyphony Magazine Pics - Various Covers

The years from 1975-85 saw electronic music realize the promise of the previous decades as monophonic voltage controlled synthesizers evolved into the polyphonic, multi-timbral music workstations of today.  The pages of Polyphony magazine documented this time of great change with innovative DIY and theory articles, interviews with the artists and engineers who helped shape the future and…

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FatMan Block Diagram

Fatman Block Diagram - Analog Synthesizer

The FatMan analog synthesizer utilizes a MIDI to Control Voltage circuit-section for conversion of Note and Pitch Wheel messages to a Pitch CV, which sets the frequency of the VCOs, and, a Velocity CV which can be routed in an adjustable amount to the VCF and/or VCA. Pitch and Velocity CVs and a key-down Gate…

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FatMan Synth Mods

PAiA Fatman Analog Synthesizer Modules

  Click here for PAiA 9308 FatMan Modifications on PAiATalk   Add LFO function to A(S)R contributed by: The Old Crow This mod adds an LFO function to the FatMan AR / A(S)R.Full details are posted on Scott Rider’s pages. VCO Hard Sync contributed by: Scott Gravenhorst As you can see, this is pretty simple.  The switch allows…

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How Vocoders Work

Vocoder Diagram

by Craig Anderton A block diagram of the PAiA Vocoder is shown below — note that it has two inputs.  Usually, one input is for an Instrument such as keyboard or guitar, while the other is for a Microphone.  Talking into the Microphone impresses vocal effects on to whatever is plugged into the Instrument input…

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How Tubes Work

Operating tubes at low plate voltages exaggerates natural warming distortions … Fig. 3 shows a typical triode vacuum tube.  Because of the Edison Effect, heat from the filament causes free electrons to boil off of an oxide coating on the cathode.  A positive voltage on the plate attracts the electrons and the moving electrons produce…

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Tube MicPre Mods

Dynamic Mics It is fairly obvious that the circuit shown above adapts the TMP’s XLR input to the increasingly popular 1/4″ balanced lines, but there is more here than immediately meets the eye.  Notice that the sleeve of a MONO phone plug grounds the ring of the STEREO jack and consequently the inverting input of…

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Tube Sound?

In the golden age of analog sound every link in the chain introduced warming distortions … If you’ve done any reading about tube amps you’ve probably noticed that much of the legendary “warmth” is attributed to the differences in the way tubes and transistors respond to overload signals.  I believe this is true, as far…

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The 9700 Chronicles

by John Simonton When we went on-line in the mid-90s I was very surprised by the interest in the Voltage Controlled Synth Modules that we manufactured during the ’70s and early ’80s.  If you’re not familiar with them there are some pictures in the photo album.  We were often asked if these modules would be reissued. …

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Frequently Asked Questions about the 9700 Series modules

I’ve heard that VCOs have to use temperature compensating resistors.  Do yours use tempcos? No, they do not.  Instead they use a diode that is part of the CV summation IC.  In practice this compensation is as good as the best of the circuits that use tempcos.  On paper, it’s better because it provides exact…

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