Taper of the Fuzz pot on the Fuzz Face

[chromesphere]

Hi all!
Built a fuzz face last night, my own layout.  Sounds as it should, looks as it should, smells as it should.  But i noticed that the fuzz pot acted a bit squashed up one end of the taper (the maximum end).  its probably normal, but i thought id ask if anyone would know if a 1kA would be a better choice or would this exacerbate the issue further?
its not critical, its probably behaving as it should...
Cheers,
Paul

[LucifersTrip]

a reverse log will spread the end

[deadastronaut]

@paul: imo the fuzz pot should be left off of this circuit,  put 1k resistor 22uf straight to ground,

but add a pre gain pot instead....much better, more control, ....  the 1k fuzz pot did bugger all ime...it was , as you say bunched at one end making it full on or off...

just my 2p.

[chromesphere]

Hey thats a really useful chart Lucifer thanks i'll hang onto that!

Rob, you know i was kind of thinking that the only good part of the fuzz turn was the last 10% anyway.  I dont think it sounded very good on low fuzz settings.  Anyway, ill keep these stock and mess around with the next one.  Probably goign to change that taper though.  1kb is useless imo.

[smallbearelec]

A few of us figured out many years ago that audio taper opens up a lot more subtleties in the FF Fuzz pot. But the direction of control is then reversed. At the time, I asked the Taiwan Alpha company to make me a 1K reverse audio pot.  I am happy to say, it has become a fairly standard choice, tho I am no longer the only (or cheapest) source for it.

Regards
SD

[chromesphere]

Thanks Steve, that makes sense! I noticed it behaved 'bunched' straight away when i was using it.  But i think i'm going to just leave it.  Because like Rob said, its almost redundant.  Max gain is almost the only good setting imo.
Hopefully get some time tonight to mess around with it some more.
Cheers!
Paul

[smallbearelec]

..like Rob said, its almost redundant.  Max gain is almost the only good setting imo.

With a linear pot, that's true. C taper opens up a different, much wider world. Add a tone stack, and you will discover just how much a Fuzz Face can do:

https://www.smallbearelec.com/Projects/FurFace/FurFace.htm

I agree that a pre-gain control is also helpful, as you can set it so that the FF effect is exactly where you want it without having to fiddle with your guitar volume.

SD

[LucifersTrip]

Thanks Steve, that makes sense! I noticed it behaved 'bunched' straight away when i was using it.  But i think i'm going to just leave it. 

It's so simple to solve the bunching problem, it's worth doing. Remember, you get close to a rev log by putting a resistor across the wiper and outer lug.  Just use a 10K pot with a 1K a resistor across it

btw, if the last 10% is what's cool, why not use a 900 ohm fixed resistor with a 100 ohm pot?

[Thecomedian]

There's ways to use resistors to make log tapers out of normal, or change the taper behavior of a real log taper pot.

I'll try to dig up the site. Presumably, you could use resistors and reverse the in/out of a pot to get reverse log taper out of a normal taper pot.

[LucifersTrip]

There's ways to use resistors to make log tapers out of normal, or change the taper behavior of a real log taper pot.

I'll try to dig up the site. Presumably, you could use resistors and reverse the in/out of a pot to get reverse log taper out of a normal taper pot.

In this case, the rev log is what is necessary and is total cake to make w/ a normal pot, as I wrote above.

edit:
http://www.geofex.com/article_folders/potsecrets/revlog.gif
http://www.geofex.com/article_folders/potsecrets/potscret.htm

Info for how to make a log pot is there, too

[deadastronaut]

Thanks Steve, that makes sense! I noticed it behaved 'bunched' straight away when i was using it.  But i think i'm going to just leave it. 

btw, if the last 10% is what's cool, why not use a 900 ohm fixed resistor with a 100 ohm pot?

thats just too simple...

[stinky]

Lucifers trip, doesn´t that pot + one resistor mess up the bias?
If I understand you correctly in the 10K pot and the 1K resistor case, then between Q2 and ground there will be nearly 1K in min and 10K in max.

[chromesphere]

Thanks for all the suggestions!
I think i may have failed to specify a requirement here.  I'm really trying not to order more parts.  Between you guys and Rob's new reverb demo video...you know...a man only has so much will power...
Paul

[LucifersTrip]

Lucifers trip, doesn´t that pot + one resistor mess up the bias?
If I understand you correctly in the 10K pot and the 1K resistor case, then between Q2 and ground there will be nearly 1K in min and 10K in max.

the 1K across the lugs (parallel) of a 10K will give you around 909 ohm with a strong reverse log type sweep.

[Solidhex]

Lucifers trip, doesn´t that pot + one resistor mess up the bias?
If I understand you correctly in the 10K pot and the 1K resistor case, then between Q2 and ground there will be nearly 1K in min and 10K in max.

the 1K across the lugs (parallel) of a 10K will give you around 909 ohm with a strong reverse log type sweep.

Stinky is right. If you attach a resistor to the wiper and an outside lug of a pot the resistance across the outer lugs changes as the pot is turned making it useless for that application. Running a resistor across the outer lugs will give a steady value but won't get you the reverse log response you're looking for. One could use a fixed resistor for the bias then use a pot with tapering resistor as a rheostat only between the electro cap and ground though.

[stinky]

If you follow Solidhex advice (which may be the best way to go if you don´t buy a rev log pot) and want to use the 1K lin pot, the resistor is a good way make the min gain setting higher.
Clean fuzz is a little boring.

[stinky]

The pot setup suggested by Lucifers Trip is really nice! Thinking it could sound interesting, I tried it out but with a 1K pot and a 100 ohm resistor. Biasing Q2 at max gain and getting the regular max fuzz, which gives a gated, broken sound in the min position of the pot. Now it's more like a blend pot, fuzz face at one side and fuzz factory comp knob at one side.
I'm sure it's old to many but it's brand new to me, and therefore fun.

[Plexi]

I had thought of using 500ohm res + 500ohm pot (...if I find one).
But maybe pre-gain pot and fixed 1k resistor solve all our problems.

Which pre-gain pot value recomends?

[thermionix]

I like 50K (linear), wired as a variable resistor, in series at the input.  I think Fulltone does the same.  For a really high gain FF maybe 100K is better.

I also like to use a trimmer in place of the 1k, and bias Q2 at the emitter instead of the collector.  More specifically, a 330R or 470R in series with a 1k or 2k trimmer, to avoid hitting zero ohms.  Bypass cap in parallel with all of that.

[Plexi]

Thanks thermionix

I'll try the usual pre-gain (lug 3 to ground) in the Lovepedal Silicon FuzzMaster.
It already have a blend knob, so I'll try pre-gain it at the input and see how it works.