fuzzface mods? trying to add diode clippers with no success!

[albatross]

Hi, I have got a npn fuzzface on the breadboard with a bc109 for q1 and a bc108c for q2, sounds great, but im trying to add diode clippers after the output cap

But they do nothing ive tried both methods as seen here at the "simple mods page" http://www.diystompboxes.com/wb/pages/build-your-own-stompboxes/stuff-to-read/simple-mods-page-2.php

Code Select Expand

Simply add back to back (anti-parallel) diodes from signal to ground after the output cap to turn a booster circuit into a distortion circuit.

You can put the diodes anywhere on the output as long as there's a blocking capacitor before the diodes.

You can put 2 diodes or 4 for more output. You can also use germanium diodes or silicon diodes.



I also tried it directly on the output, but still nothing, why doesnt this work with the fuzzface?


Oh on my adventures I found swapping the output cap to a 0.47 gives a nice bassy tone and maybe good for bass? I also changed the input cap to a non polar 0.1, and I think it sounds better.

[Meanderthal]

Oh on my adventures I found swapping the output cap to a 0.47 gives a nice bassy tone and maybe good for bass? I also changed the input cap to a non polar 0.1, and I think it sounds better.

I've settled on 1uf film box caps for both input and output, and found it to be very effective on both guitar and bass.

As far as the clipping diodes, I can't think of a reason for them not to work(other than it's already distorted, and just maybe subtly changing the clipping)... try maybe before the output decoupling cap... or, maybe it's the diode type...

[petemoore]

  Ge;s with low clipping threshold.
  maybe the voltage peaks aren't breaking over the diode thresholds enough.
  I've tried this with a FF and it can be a small difference where the circuit clips and where the diodes clip, other times, and with the Lava Rim II I could hear diode selection or adjustment.
  Maybe something else.
  2k gain resistance and 2n5088's or high gain transistors.
  Actually isn't the 109 the higher gain entry of the BC, with the 108 being lower ? Try the higher gain Q's in Q2..did you socket?

[albatross]

Ive tried before the output cap and just after , then on the actual output, after the 500k vol pot lug 2, and using 4 like the pic suggests, but when testing unplugging/plugging the diodes or ground wire from these diodes whist strumming, theres no difference at all.

Im using 1n4001's at the moment, just experimenting . strange ;

Hi pete, yeah im using a breadboard, so everything is socketed, im sorry i already had the bc109 in q2, i just swapped round and i notice its quieter and more finicky

[joegagan]

ck the the dinosaur fuzz.
it is a hotrodded fuzzface with a third gainstage.

the third stage gives enough gain to really drive some si diodes wild baby.
here is a modded dinofuzz that shows a working solution to your problem. you don't have to build the whole circuit, just add the third stage as shown, it will work.

[petemoore]

Ive tried before the output cap and just after , then on the actual output, after the 500k vol pot lug 2, and using 4 like the pic suggests, but when testing unplugging/plugging the diodes or ground wire from these diodes whist strumming, theres no difference at all.
  You want to put the diodes after the DC blocking cap.
  "using 4 like the pic suggests'
  a string of two seriesed Si diodes is a high clipping threshold [I get the idea you have 2 BTB pairs], one BTB pair is half that, Ge's...well measure the diode configuration thresholds, I don't know what FF outputs typically range at, but lowering the threshold of the clipping elements might make evident clipping.
  Joe's plan of boosting before re-clipping would get the voltage to easily break over the diode threshold..1 btb pair there.

[Meanderthal]

 That's a really cool tone control Joe... not yer average lowpass on the tail...

[joegagan]

meanderthal thanks but I didn't think of it myself. someone suggested it to me in 2000, possibly Oskar Bruil but he credited Jack Orman.

almost all of my designs utilized some form of it, i love it

[Gus]

Think about the signal level

Did you use the split resistor collector and take the output from the "standard" FF place (node of the two Q2 collector resistors)?

Take the output from the collector of the 2nd transistor, move the output cap connection to the collector.

You are remaking a circuit kind of like the EH one below


http://www.generalguitargadgets.com/diagrams/muffsc.gif

[petemoore]

  THere it is...
  I used to routinely wire FF's off the collector [among other mistakes] and wonder 'why so fierce and hot?'.

[albatross]

Hi

Thanks for all the helpful feedback (pun intended! )

Sorry for the late reply as ive been asleep, I tried gus's method and it works now , it is very loud before i add the diode clippers, then once added it sort of tames the volume

Feirce and hot is the best way to desribe it like petemoore said !

It needs a bit of work i reckon as its very nasty sounding when pots are cranked all the way, but sounds ok if not quite all the way, downside is : when rolling down the volume, the characteristics of the fuzzface are now gone but that was expected.

Im gonna try adding the 3rd gain stage as mentioned above now .

Thanks!

[albatross]

Heres a waveform from a software oscilloscope, showing the difference so far:

1st is a stock fuzzface cranked
2nd is the fuzzface with input cap changed to 0.1 and output cap, with the diode clippers section.



what type of waveform is that ?