Gretsch Expandafuzz

[tommy.genes]

Any thoughts on what this is?
-- T. G. --

[Mark Hammer]

Well, the Controfuzz is a quirky, but interesting, beast.  While it provides sizzling fuzz, and a fuzz/dry blend, it does so in a manner that creates the illusion of a sustained note getting fuzzier towards the end.  Too often overlooked, well worth building, and a fairly simple circuit on its own.

The Expandatone part looks like it probably contains three filters, with level control for each, as opposed to a 3-band EQ.  My hunch is that it uses three separate paths because the footswitches likely cancel/engage each separate path.  There were a number of products in the early 70's that adopted a similar approach, so I'm thinking Gretsch just did the same thing.

The question for me is where, in the overall circuit, the filters are situated.

[R.G.]

Yeah, what Mark said!

And if you'll take good high res photos and post them or mail them to me, I'll reverse engineer it.

[tommy.genes]

Unfortunately this is just a picture I found on the web so I can't get any gut shots. It did start me thinking that a generalized disto box with foot-switchable or rotary-switchable voicing could be a neat project. Kinda like multiple distortions in one box - but with a lower parts count.

Too bad I never seem to find the time to get these projects beyond the "thinking" stage though.

-- T. G. --

[Austin73]

Does look kinda coool,


Just done a quick search and found people on Harmony Central who own them. Have posted a request for gut shots, Hopefully they will be kind enough to help out.

Then I will pass them on to RG and let him do his magic.

Aus

[Wild Zebra]

Yes, this seems like it could be a fun little, well big pedal.  Hopefully something will turn up.  I poked around for a schem yesterday to no avail.

[DDD]

4 (four) stomp switches inside 1 (one) box is a serious attempt for the Guinness record. :-)

[Rodgre]

Unfortunately this is just a picture I found on the web so I can't get any gut shots. It did start me thinking that a generalized disto box with foot-switchable or rotary-switchable voicing could be a neat project. Kinda like multiple distortions in one box - but with a lower parts count.

Too bad I never seem to find the time to get these projects beyond the "thinking" stage though.

-- T. G. --

Not a DIY pedal, but the Jacques Fuse Blower has a pretty unique concept in a similar vein. It seems to be three distortion circuits, or else three frequency ranges that each have their own level. You can blend the three ranges to get many cool and unique distortion tones. We have one at Tremolo Lounge.



Roger

[R.G.]

Not a DIY pedal, but the Jacques Fuse Blower has a pretty unique concept in a similar vein. It seems to be three distortion circuits, or else three frequency ranges that each have their own level. You can blend the three ranges to get many cool and unique distortion tones. We have one at Tremolo Lounge.

Cool - that's one less range/distortion than Anderton's Quadrafuzz, which has pretty much the same description.

[Rodgre]

Not a DIY pedal, but the Jacques Fuse Blower has a pretty unique concept in a similar vein. It seems to be three distortion circuits, or else three frequency ranges that each have their own level. You can blend the three ranges to get many cool and unique distortion tones. We have one at Tremolo Lounge.

Cool - that's one less range/distortion than Anderton's Quadrafuzz, which has pretty much the same description.

I keep forgetting about the Quadrafuzz. That's one of those things that I've wondered about building since I first saw it in Guitar Player way back in the day (I think the issue had Eddie Cochran on the cover!) but the description made me pass it up. The Quadrafuzz seems to be 4 separate fuzzes fed from 4 crossed-over frequency ranges, which supposedly sounds more "clear" with less inter-modulation distortion when playing chords. This is also the sonic concept of the Hexaphonic Fuzz built into the old Roland guitar synth controllers (I have the strat-like G-505). The Hex Fuzz has never been very useful or inspiring to me, as I am more of a fan of less-tame distorted tones, with lots of harmonics and possibilities for mayhem.

On the other hand, the Jacques isn't like those. The 3 distortion bands don't sound like they're crossed-over or filtered to affect certain ranges. They sound like 3 circuits fed by the same signal, but with their tones altered one way or the other to do their thing at different tonal ranges. Sort of like "Blow 1" is a heavy and woolly fuzz, "Blow 2" has a barking midrange, and "Blow 3" is kind of like a treble-booster/fuzz. It's not as polite sounding as it might imply.

Back to the Roland Hex-Fuzz, there is a Squeeze song that I'm trying to recall, whose guitar solo sounded like it was done with the Roland. It is a unique sound, but like I said, very polite and neat. In that respect, it does sound more synthy than guitar-like, though it is still just the sound of the hex pickup divided and run through 6 mild fuzzes. The fuzz effect is reminiscent of the distortion built into Jazz Chorus amps.

Roger

[caress]

i've built the quadrafuzz and i wasn't all that impressed by it...  the four frequency bands only have subtle tonal differences from each other.  i added some switches to change the caps/frequencies of each band and that helped a little bit to change up the sound a bit, but even then the effect is only marginally more useful.  as for less intermodulation, i'm not too sure if i can hear it...  my quadrafuzz really only goes from fuzzy to really fuzzy anyways - it doesn't really do subtle, so the fact that the frequency band fuzzing "clears" things out is kind of lost on me.  i think a two or three band fuzz with distinct tonal differences between the bands would be far more useful, IMO...

[Austin73]

hey guys come back to the expandafuzz! lol

Just to let you know how I'm getting on I almost got a schem for it but somebody is being an arse! heres the link so far if I get a shem will post it or send it to RG

Cheers and merry christmas

Aus

[Austin73]

forgot tp put link up

http://acapella.harmony-central.com/forums/showthread.php?t=1835208

Aus

[foxfire]

funny i don't feel like a douche bag. well not right now at least.

[Rob Dobbs]

Thats my pedal in question. Ive had it near 20 years now.
Why is anyone being called names?

Ive plans to get together with a peadl builder localy in regards to a white noise pedal and see what he thinks of the Expandafuzz. Its more in regards to helping out a friends band than anything personal. Until then, I wont post any pics of the schematic.

[Mark Hammer]

The Quadrafuzz splits the signal up four ways before clipping.  Though I am still operating in the dark here, the original Controfuzz likely does not work in that fashion, given the controls we see on the chassis, and the PCB pattern we see on the linked-to forum.

The most basic shortcoming of the Quadrafuzz, aside from misguided expectations, was the manner in which the clipping sections were not really compensated for the different starting levels of the different bands.  Huh?  The clipping diodes have a specific threshold that must be met to achieve clipping.  *IF* it was the case that the signal in each of the different frequency bands started out at the same aplitude, then applying the same amount of gain in each band would yield the same amount of clipping for each band.  The trouble is that each clipping section applies the same amount of gain, even though the higher up you go the lower the starting amplitude of the input signal.  While I have not actually built or played through a Quadrafuzz, it just seems to me that more people could get what they want from it by changing the value of the feedback resistor in each of the clipping sections to more reliably produce the same amount of clipping in each band.

[caress]

The Quadrafuzz splits the signal up four ways before clipping.  Though I am still operating in the dark here, the original Controfuzz likely does not work in that fashion, given the controls we see on the chassis, and the PCB pattern we see on the linked-to forum.

The most basic shortcoming of the Quadrafuzz, aside from misguided expectations, was the manner in which the clipping sections were not really compensated for the different starting levels of the different bands.  Huh?  The clipping diodes have a specific threshold that must be met to achieve clipping.  *IF* it was the case that the signal in each of the different frequency bands started out at the same aplitude, then applying the same amount of gain in each band would yield the same amount of clipping for each band.  The trouble is that each clipping section applies the same amount of gain, even though the higher up you go the lower the starting amplitude of the input signal.  While I have not actually built or played through a Quadrafuzz, it just seems to me that more people could get what they want from it by changing the value of the feedback resistor in each of the clipping sections to more reliably produce the same amount of clipping in each band.

really great point mark.  in my opinion, though, each frequency band was not distinguished enough from the next; that is, there weren't enough frequencies rejected outside of the clipping frequency. 

[Mark Hammer]

in my opinion, though, each frequency band was not distinguished enough from the next; that is, there weren't enough frequencies rejected outside of the clipping frequency. 

That could be easily addressed by improving the filter selectivity, maybe via another pole of filtering.

[Austin73]

Hey Rob thanks for coming over and chatting. Sort of started a bit of a hornets nest with the Dauche thing , god knows why.

If your planning a white noise pedal you could always ask advice on here as we area friendly bunch.

Sorry for asking for the schem just that some of us want to try it in other pedals we make or to adjust it to make more fun.

Hope you can help eventually and good luck with the project.

You should check out the other stuff on this site as we have lots of fun projects and really top chaps that really do know their stuff and are happy to help

Welcome Aboard

Aus

[analogmike]

I have two of them, checked and one has the schem