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Author Topic: Popular Electronics Amp Fuzz/Tremolo Circuit  (Read 1326 times)

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jrod

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Popular Electronics Amp Fuzz/Tremolo Circuit
« on: February 23, 2010, 02:02:02 PM »
Here is a copy of a Fuzz/Tremolo portion of a amp project from Popular Electronics magazine circa 1968. Maybe the fuzz circuit can be extracted for a stand-alone unit. I am not really sure what is going on in the circuit. Looks like there are some extra parts than the usual fuzz circuit Also wondering if the section after the tone circuit is there to boost vol. back up or is part of the trem. circuit.

Enjoy!
« Last Edit: February 24, 2010, 09:23:02 AM by jrod »

CountryBoyAtHeart

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Re: Popular Electronics Amp Fuzz/Tremolo Circuit
« Reply #1 on: February 24, 2010, 09:20:54 PM »
The fuzz control is acting as a variable boost, my only concern is that it will mainly add boosting to the bass frequencies rather than treble, which may lead to muddiness rather than just fuzz.

The DpSt adds clipping diodes as well as a 50n cap parallel to a 5uF (Remember, caps divide in series and add in parallel), as far as I can remember, that should help with harshness of the treble. it won't add much more frequencies in compared to the 5uF it's paralleled with. Idk about that whole sawtooth comment, doesn't make much sense to me how that would work because of the cap. You'll need a pot with a switch to accomplish this the way the schematic & text refers to it, a stand alone switch may be neat as well.

I don't think it's that impressive personally. Just a fuzz with a pot and built in switch. The post fuzz part of the circuit is where it gets interesting for me. Q3 splits the signal and Q4 sends it to the output. Q3's emitter then goes to the trem part of the circuit. That's where I run out of help, I'm not that informed on phasers and trems and such.

S2 looks like a bright switch. The volume pot is just an attenuator/ voltage divider like any standard volume pot.
-Jared

N.S.B.A. ~ Coming soon

jrod

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Re: Popular Electronics Amp Fuzz/Tremolo Circuit
« Reply #2 on: February 26, 2010, 11:20:55 AM »
Thanks for the info CountryBoyAtHeart.

Yeah, it probably isn't really ground breaking, but thought I'd post it since I'd seen it floating around.

Q3 & Q4 are interesting. My initial thought without looking over too hard was that they were for gain recovery after the tone circuit.

Thanks again for your insight.