eti fuzz "struzz" hacks (AKA GEU Octaver Fuzz)

Started by pinkjimiphoton, March 31, 2017, 10:54:25 PM

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pinkjimiphoton

hi guys,
i got some bends for this circuit if ya wanna play with 'em.
the actual schematic is indeed the eti fuzz "struzz"
i reccomend doing the following
ditch the 560p cap. ditch the q1 emitter resistor, replace with a jumper.
i like using two separate opamps, and prefer a lm308 or 741 in ic1, and a LF356 in ic2. but a dual opamp is fine, too
use mpsa13 for the transistor
make the diodes water clear green led's. mind the orientation, this isn't a diode clipper in this config (tho a diode clipper will work kinda) it's a rectifier.
ditch the 39k/820r voltage divider and replace it with a 50k linear pot. now ya got volume control of the fuzz side.
ditch the 1k/560r (1k/1k on the schematic) voltage divider for a 1k pot. now you can adjust the volume of the octave side. the sustain will still affect both sides.
i didn't like the fact that there was no dc blocking cap on the output of this.
on the circuit board, i just cut the trace between the footswitches and stuck a 470n to bridge it. no dc worries, slightly smoother sound on the output.
more balls to the fuzz, better drive to the octave side and it will track better and cleaner.
if you wanna break the node the diodes share and put a switch there to connect/disconnect it, you can get a very kinda cool buzzy farty octave downish kinda thing that will track to about your 12th fret on your high e string. once ya go higher, it will die. if ya strum a low string, you can play again.
its kinda insane and not worth a switch really, but fun. and it has a huge effect on the octave side. you loose the fundamental cancellation but still get a noticeable amount of the octave effect.
and for extra fun, ya can mount the led's to the front of the enclosure, they will glow when you play, and will get brighter the harder you play.
it cleans up a little better too from the guitar.. never gets clean clean, but similar to turning down into a cranked tube amp on the dirt channel. it gets quieter and kinda cleaner, but... not all the way.
those are my hacks to it. if ya try 'em, let me know.
peace guys
pink

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pinkjimiphoton

here's a modified schematic and vero layout.
i haven't built the vero, but it's based on miro's excellent verified layout on tagboard effects. i just took a different approach
so it has 3 knobs now instead of just one. also included a daughterboard for +/-9v with an 1cl7660. added a pull down resistor on the vero for the fuzz switch, an output cap and a couple limiting resistors so ya don't smoke your pots.

zmokink yer pots is no good for you. ;)

i've built this on the old graymark kit boards and its a lot of fun and a fairly easy build. anyways...
vero



moddified schematic



this way, you can get the fuzz a little over unity, or turn it down to a useable level. same with the octave side. sustain affects both sides of it still. it sounds pretty good, and the octave part tracks well. if you REALLY want to, you can put a master volume pot on it, but it's just overkill, as ya can set the volume of the fuzz and octave independently.

if ya build it, have fun. peace!

imho, it sounds best on a 9v battery, but YMMV
  • SUPPORTER
"When the power of love overcomes the love of power the world will know peace."
Slava Ukraini!
"try whacking the bejesus outta it and see if it works again"....
~Jack Darr