I have 6 working 901bs in my 3C DIY 3C system however I may have a problem…compared to the Synth.Com oscillator the 901b’s only kick out about a third of the volume output from each waveform ..is this normal?
My Oakley Osc. also kicks out about two thirds more power than the 901b’s…
if anyone’s got these in their system have they noticed this? not having a true Moog Modular anywhere near to compare is quite frustrating.
That sounds about right. Most newer modular VCO’s have a very hot signal compared to the older Moog oscillators, typically 10 volts peak to peak.
From a 901 spec sheet:
Fixed level outputs 0.5 volts RMS (-4dB)
From dotcom Q106 spec sheet:
Waveform Levels: 10V PP
This is the way mine work, most other brand 10 V P-P oscillators will distort the CP3 mixers at any setting above 2, making them useless without some attenuation to bring them down to Moog levels. The CP3 will boost the 901, as the CP3 will double each input, and there are 4 inputs.
The old Moog modular with 901’s and CP3’s is a balanced synergy to get those unique tones.
The reason for that was the voltage rails of the original moog modulars. They were (+)12 and (-)6 volt rails. Small wonder that 10VPP waveforms will distort the CP3 circuits.
The rails were oddball because the early opamps from the 1960s couldn’t operate on rails hotter than that. Damn those advances in technology…
well..I couldnt ask for better answers…thanks! (good to know my 901b’s work as they should)