Jen Fuzz & Sustain - - -
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- John Lyons
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- SonicVI
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Re: Jen Fuzz & Sustain - - -
"automatic gain control" aka compressor/gate.sir h c wrote:The UA757DC is a variable gain stage (well two) that is usually used for a radio AGC (automatic gain control) circuit. I wonder if something is wrong with yours, as I would guess that there should be some range of gains available. Still very different than a big muff inside.
I'm gonna guess the 741 is set up as a schmitt trigger like in the MXR Blue Box or Anderton Ultra-Fuzz to give a very squared off synthy distortion and the trimpot sets the sensitivity of the fuzz input. Then the 757 is being used as a gate to cutoff the decay of the fuzz which can be very unnatural with schmitt trigger fuzz circuits. The Blue Box uses a simple pair of transistors for its gaiting. Then the transistor is a buffer for the blend circuit.
"If you want to write rock lyrics you must learn about where the Hobbits dwell."
- edkoppel
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i was bored.
here's another one///
here's another one///
Oh, DB? That's just slang for Dandy Big muff collector.
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Tone Machines, Vintage Effects Blog: www.tonemachinesblog.com
Instagram: https://instagram.com/ed_skymall
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Re: Jen Fuzz & Sustain - - -
Okay, on the ua757, pins 3+4 (connected together)are the AGC stuff. That looks to go to the sustain pot for some control. I don't think so much gating, as that would make this chip so overkill, why not just the 4 transistor FZ-1B circuit for that. What voltage is on these pins? With no input it should be around .8V, and with max signal and max gain reduction, 3V according to the data sheet. The chip has a maximum gain of 74 dB! That is insane amounts if it is ever set that low, but at max attenuation, the gain is about 2 dB. I am now thinking of building something with a similar IF chip that I have lying around...
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