Fuzz Face - gain pot range

[kapsel]

Hi everyone,

Sorry for another noob question.

I built a NPN Si Fuzz Face using this scehmatic: http://fuzzcentral.ssguitar.com/fuzzface/fuzzfacenpnschematic.gif
Overall it works well and the sound is very good, but only when the Fuzz pot (1K lin) is maxed out. As soon as I turn down the pot, from 90% and less, all the "distortion" is gone and a "muddy" non distorted sound is produced.
1. Is this normal?
2. Would changing the pot value (maybe using a bigger value?) help with it?

Again, sorry for the noob question, I think pots and the way they work are the hardest thing to grasp at this early stage  .

Cheers

[Thecomedian]

http://www.geofex.com/Article_Folders/fuzzface/fffram.htm

Maybe this will help. Gain is important to the original fuzz face circuit. That is, the gain of the transistor. You might not have enough gain.

I used a 2k pot because thats all I had at the time for my fuzz circuit, and it allowed more range for fine tuning, but then the DC bias changes.

What transistors are you using?

[kapsel]

Hi, thanks for the reply.

I used a BC108 and a 2N5088 simply because they sounded better (I mean I didn't measure their gain).
At first I used 2 BC108s but the sound was horrible, and with 2 2N5088s the sound was good but more like a distortion and less fuzzy. A combination of the two seemed to produce the best results.

Thanks for the info, I will study the article later on.

[deadastronaut]

imo, take out the 1k fuzz pot , put a 1k resistor and the 22uf straight to ground instead...

now add a 250k pot at the input of your circuit..(pre-gain...)  it has a much better control over the gain, regardless of hfe etc.....

the fuzz pot is useless imo..

[LucifersTrip]

Hi everyone,

Sorry for another noob question.

I built a NPN Si Fuzz Face using this scehmatic: http://fuzzcentral.ssguitar.com/fuzzface/fuzzfacenpnschematic.gif
Overall it works well and the sound is very good, but only when the Fuzz pot (1K lin) is maxed out. As soon as I turn down the pot, from 90% and less, all the "distortion" is gone and a "muddy" non distorted sound is produced.
1. Is this normal?
2. Would changing the pot value (maybe using a bigger value?) help with it?

Again, sorry for the noob question, I think pots and the way they work are the hardest thing to grasp at this early stage  .

Cheers

was just writing the same thing (sadly, that happens with a bunch of builds, which is why you'll read a lot of posts here saying that the fuzz knob is useless. many set it at full and use a pregain like this:)

here's an example:
http://www.freeinfosociety.com/electronics/schematics/audio/pictures/joegaganeasyface.gif

in addition, more on the si version, when the vol is below the top 25%, it can also get a bid muddy. you can put a small cap (try .001uF to start) from wiper of vol pot to the non-grounded side. additionally, you can try a 250K pot instead of 500K

[kapsel]

Ok, very useful comments, thanks a lot guys, I will try these when I get back home 

[nocentelli]

A 1kC, i.e. reverse log taper, is better than 1kB (linear) which in turn is better than a 1kA audio/log pot.

[zombiwoof]

A 1kC, i.e. reverse log taper, is better than 1kB (linear) which in turn is better than a 1kA audio/log pot.

Small Bear sells a reverse log 1k pot exactly for this use.

Al