Japanese Book Fuzz

[lepra85]

Hi everyone,
I would like to build the following Fuzz:
http://experimentalistsanonymous.com/diy/Schematics/OOP%20Japanese%20Electronics%20Book/fuzz-with-tone.gif


I like very much the the simple that it is.
I saw that the pedals of this book are quite popular, but I didnt find one build report or reviews regarding this circuit.
does anyone built this pedal?

thanks,
Lepra85

[merlinb]

It would be faster to breadboard this circuit than to read a review... or this post.

[Mark Hammer]

Could be interesting.  If installed into a wah shell, it can easily be a fuzz-wah, or rather, an overdrive-wah.

Gonna need a bunch of mods to run off +9v, though.

[mac]

First opamp gain is fixed at 100. Think Mxr Dist+ :-)

mac

[anotherjim]

I haven't built it, but the filter option could be interesting - tune your mids. Could work as second stage option for tube screamer too? Hmmm....
If you don't mind running from 2 batteries, as it is, it will have more clipping from the diodes  compared to a single 9v design like the Dist+ where the input amp is doing most of the clipping during note attack.

Note: the input is tuned to work from direct passive guitar input - it won't sound as intended with anything else in between.

[lepra85]

Yes Mac, anotherjim,
seems like a MXR Dist+, the subtle difference is that in the Fuzz gain stage have no cutoff for low frequencies.
The lack of limitation in the low frequencies is what I expect to be the cause the Fuzzy sound.

[Mark Hammer]

A gain of 100 is actually less than what a Dist+ delivers.  If I were building this thing, I'd replace the 10k ground-leg resistor with a 2k2 in series with a 50k pot.  That will give gains ranging from around 20x to around 455x.  The Dist+ max gain is 213x.  A 10-33pf cap, in parallel with the 1M feedback resistor would help things along.

You will note that, because it uses a bipolar supply, it omits any DC-blocking capacitors.

[mac]

The lack of limitation in the low frequencies is what I expect to be the cause the Fuzzy sound.

A flat response in the first stage before all the filtering in the second one?

Another thing I would do is to change the Q. A pot instead of the 100k after the diodes can do it.

mac

[lepra85]

A flat response in the first stage before all the filtering in the second one?

Yes, reaching the clipping "stage" without cutting the low frequencies will produce the fuzz (I suppose).