Introducing: Soapwater Fuzz

[JimRayden]

It's a fuzz. Not a particularly good sounding one, doesn't have much sustain nor "the Ge-tone". It doesn't suck either. Sound-wise, it's the most generic fuzz on earth. Circuit-wise, not so...

I was browsing my old HDD for schematics and stumbled upon the schemo for my Vermona Regent 300K amp (which I still use once in a while). I had never actually used the fuzz channel but tried it again today and found it rather pleasant. So I took the plunge to share it with you for some improvements to make it into a DIY-project.

At first glance it looks like another FF but it has some additional feedback thing going on, plus the dual-gang control. This circuit is designed to be at unity volume at all times because of how the amp's channels are set up. First thing I'd do is ditch that 47k resistor and run 9V into it. I'd also split the dual gang into two individual pots and lose the 220k in the end. Let me know of any other improvements and I'll update the schematic.

Coming up with the name was rather simple 'cause it does sound like soapwater. Pretty dull but has some splatty/squishy feel to it. Excellent for just dirtying up yer tone without that annoying sustain increase that distorting devices often feature.

In conclusion, I think it's simply a pretty cool circuit. If you need any additional information about the amp, just ask.

Soon to come: Soapwater Tremolo

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Jimbo

[brett]

HI
Cool circuit
It's slightly unusual that Q2 runs flat out, while Q1 is controlled with the "fuzz" pot, rather than the other way around (like in the FF).

That feedback path from Q2 collector to Q1 emitter has some interesting possibilities, such as using a 10k or a 25k pot in place of the fixed 10k resistor.
cheers

[JimRayden]

The funny thing about this circuit is that when the input is slammed, it doesn't introduce mad anounts of distortion, sustain and gain, it rather starts acting as an extreme compressor. So driving a booster into it will just produce a quieter fuzz sound. Must be one of the features of that funky FB setup.

I'll get some sound clips of the amp today.

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Jimbo

[Rob Strand]

Circuits using the underlying FF circuit bit with feedback from Q2's C to Q1's E were very common in the pre-IC days; there's a few minor variants.  I don't think that circuit has has been abused enough for distortions effects though.  There might be scope for something good to come out of it for lower gain FF's.

The well known ColorSound overdriver uses it:

http://home.hawaii.rr.com/stompbox/CSOVR.JPG

(from Aron's old schematic page).

[joegagan]

thank you for posting this, it is very fun to look at.

coupla interesting twists as mentioned.

[DDD]

As far as I remember,  Vermona Regent is from German Democratic Republic, isn't it? I've tried some Regent power amps, and have to notice they are "well done" and very reliable.

[JimRayden]

As far as I remember,  Vermona Regent is from German Democratic Republic, isn't it? I've tried some Regent power amps, and have to notice they are "well done" and very reliable.

You are correct. The schematic is 1981 and my particular amp is '86, the Wall era.

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Jimbo

[Steben]

Circuits using the underlying FF circuit bit with feedback from Q2's C to Q1's E were very common in the pre-IC days; there's a few minor variants.  I don't think that circuit has has been abused enough for distortions effects though.  There might be scope for something good to come out of it for lower gain FF's.

The well known ColorSound overdriver uses it:

http://home.hawaii.rr.com/stompbox/CSOVR.JPG

(from Aron's old schematic page).

negative Feedback. Gain is determined by (Zfeedback)/Z(bypassed emitter)
Max is here 10k/100= 100.

Good for controlleable gain with high gain transistors. Bad for smooth compressed germanium sounds.

[JimRayden]

Whoops, recorded it but forgot to post. Strat into the Vermona 300K into two 12" celestions mic'd.

Mp3 Clip

Here you go, sounds like a spongeful of soapy water to me. The sponge is a bit more "wet" in real life though.

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Jimbo

[Stompin Tom]

Huh... it does sound like a soapy sponge... good name.

[mac]

What kind of transistors are these? Si most likely... 

mac

[JimRayden]

Yep Si, couldn't find a datasheet though.

[EDIT] And this just gave me another idea for this months FX-X.

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Jimbo

[mac]

And this just gave me another idea for this months FX-X.

Yeap. Me too.

mac

[Austin73]

Hi Guys,

Am I missing something or is the schem for the sponge missing? I can't seem to see it.

Aus

[JimRayden]

Hmm, works for me, server seems to be okay. Can you hear the sound sample?

Try the copy-the-address-into-a-new-window trick.

http://www.wheatoninvestment.org/playout/schematics/soapwater.gif

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Jimbo

[Dingleberry Electronics]

Tre transistors merked SC239 were most likely 2SC239.
Probably a BC239 will do the job correctly. There is also BC237 and BC238 which will do fine.
I think BC107, BC108, BC109 will all work wery well too.
And don't forget BC547, BC548, and BC549.
All of those comes in three different gain ratings. a, b and c where a being lowest and c highest gain.
If you can get some BC183b's try them. It was used in many fuzz boxes during the seventies.

Actually probably any NPN will work i that circuit, but it's good try different transistors and let your ears decide.

-T.E

[mac]

Hi Guys,
Am I missing something or is the schem for the sponge missing? I can't seem to see it.
Aus

I had to click a couple of times to hear the sound sample. I got the classic 404 error and then it worked.

Actually probably any NPN will work i that circuit, but it's good try different transistors and let your ears decide.

I wonder how a couple of Ge would sound.

mac

[JimRayden]

mac, if you want to use this as this month's fx-x entry, you're more than welcome. I will be working on something else this month anyway.

And I wanna hear if it gets any soapier or spongier with Ge's.

--------
Jimbo

[mac]

I like to replace Si with Ge... BMP, Bazz Fuss, Joe Davisson's opamp, Jordan Bosstone, Rocket, etc

Actually I'm on the Harmonic Percolator, there is a new thread about it, and also trying to re-desing the Fuzz Face to be more temperature stable with the addition of one resistor, which very similar to the soapwater. 
Keep you informed.

mac

[Isaiah]

This circuit looks really interesting.

Someone mentioned that it doesn't sustain very well,
but the last chord in the clip rings out for quite a while.

Would it be possible for someone to make clips using a bass guitar please?

I'm wondering if the circuit would be any good for Sunn O))) / Boris-like drones because
of the squishy/compressing feel to the sound (I'm not sure how drastic that effect would be...)

Thanks,
Alex

EDIT -
I realise that a big part of the Sunn O))) sound is the cranked Model Ts and the excessive (debatable  ) volume.
I'm looking into building one of 3 fuzzes that don't use diode clipping (I find they feel different to me) for going some way to generating feedback.
They are - Tonebender Mk II, MIII and this fuzz.