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DIY Stompboxes => Building your own stompbox => Topic started by: DJPsychic on March 12, 2021, 05:22:41 PM

Title: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 12, 2021, 05:22:41 PM
Might be a dumb question, but if I put a 300-500k volume put on a Fuzz Face after the input, would this respond like the volume pot on a guitar?

I currently use the 50k fuller bias at the input, would bumping up to 500k give me more "cleanup" range?

Thanks as always  :icon_cool:
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: iainpunk on March 12, 2021, 05:40:17 PM
yes, it does that.
the FF's i build all had that style ''gain control'' and had the other gain control hardwired at full gain.

cheers
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 12, 2021, 05:50:37 PM
yes, it does that.
the FF's i build all had that style ''gain control'' and had the other gain control hardwired at full gain.

cheers

Nice! I typically have a 50k @ input, 1k gain, then 500k vol...will experiment with a 500k at input as well


Thank you!
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: iainpunk on March 12, 2021, 06:54:16 PM
ow, i use 250k for this 'trick' (and all my guitars), but 500k would probably be fine. you might want to put a 10k or 22k 'stopper resistor' in between the pot and ground

cheers
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: Big Monk on March 12, 2021, 07:19:48 PM
yes, it does that.
the FF's i build all had that style ''gain control'' and had the other gain control hardwired at full gain.

cheers

Unfortunately, the “Fuzz” control on a Fuzz Face is useless compared to the “Attack” pot on a Tonebender MKII.

I put this “Pre-Gain” pot on my Tonebender MKII and between guitar volume variations, “Attack” pot settings, and “Pre-Gain” settings, there is a whole plethora of distorted tones to be had.
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 12, 2021, 07:42:21 PM
ow, i use 250k for this 'trick' (and all my guitars), but 500k would probably be fine. you might want to put a 10k or 22k 'stopper resistor' in between the pot and ground

cheers

Interesting the "input" pot I use aren't grounded Just lug 1 and wiper. Also are you using linear or log?
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 12, 2021, 07:43:43 PM
yes, it does that.
the FF's i build all had that style ''gain control'' and had the other gain control hardwired at full gain.

cheers

Unfortunately, the “Fuzz” control on a Fuzz Face is useless co pare to the “Attack” pot on a Tonebender MKII.

I put this “Pre-Gain” pot on my Tonebender MKII and between guitar volume variations, “Attack” pot settings, and “Pre-Gain” settings, there is a whole plethora of distracted tones to be had.

I love the sound of a rolled back fuzz  :)
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: ashcat_lt on March 12, 2021, 08:20:45 PM
Interesting the "input" pot I use aren't grounded Just lug 1 and wiper. Also are you using linear or log?
The series resistance of your pot over the low input Z of the FF probably does fine for full range voltage division anyway, unless you really want to get to silence.  That same series resistance will also tend to isolate the inductance of the pickups from the low FF input, so you get some of the treble back at the same time. 

More simply put, the FF input basically IS the grounded lug of the "pot" plus a stopper resistor already.  :)
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: iainpunk on March 12, 2021, 08:44:44 PM
Quote
Interesting the "input" pot I use aren't grounded Just lug 1 and wiper. Also are you using linear or log?
i doubt it actually matters if you use it as series or with a grounded lug, the grounded lug would probably give you a deeper cut in gain.
i use log, for gain, volume, etc.
you can also add a bright cap if you want more distortion instead of fuzz when you turn down the gain.

cheers, Iain
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 13, 2021, 09:26:26 AM
Edit:

More noob questions:

What are the tonal differences between using a B250k and a A250k in this position? Am I still accomplishing the same thing but on a different curve?

The A250k I have in does it's job cleaning up, but there's only about a 1/4 turn that has an effect on the signal.

I tried a B250 and a B500k - there seems to be a bit more useable range.




Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: anotherjim on March 13, 2021, 11:15:47 AM
Some have gone as far as building a guitar sim to go between a buffered pedal and ye olde fuzz.
Completely passive, a winding of an audio transformer in series with the input stands in for the pickup inductance with a guitar vol & tone to output.
I keep meaning to make one.
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: iainpunk on March 13, 2021, 05:18:52 PM
Some have gone as far as building a guitar sim to go between a buffered pedal and ye olde fuzz.
Completely passive, a winding of an audio transformer in series with the input stands in for the pickup inductance with a guitar vol & tone to output.
I keep meaning to make one.
i build something similar for a friend, using a ua741 with a gain trimmer from 0db to 6db (unity to 2x gain), going in to a guitar pickups with its magnet removed, and through a volume and tone pot like a strat is wired.
Edit:

More noob questions:

What are the tonal differences between using a B250k and a A250k in this position? Am I still accomplishing the same thing but on a different curve?

The A250k I have in does it's job cleaning up, but there's only about a 1/4 turn that has an effect on the signal.

I tried a B250 and a B500k - there seems to be a bit more useable range.
it doesn't make a tonal difference wether you use log or lin pots, resistance is resistance, independent of the wiper sweep.

cheers
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 16, 2021, 06:56:34 AM
Another few more noob questions:

- What is the actual difference between using the 500k pot and the 50? I understand it's "more resistance" but how is it effecting the original signal?

- Are both the 50k and 500k when maxed letting in original signal or are they "boosting" it to their respective resistance? Like am I effecting the tone the same with both pots, just on a wider range? Or am I adding more gain with the bigger value?

- With the 500k, It only really has in effect in the last 1/3 of a turn. Is there a way to just have that range of resistance spread out through the entire range of the pot? In other words, letting the user dial in a more precise tone.


Sorry for the clunky wording, these are probably super dumb questions. not an engineer, just really enjoy building fuzzes

Thanks again
 



Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: iainpunk on March 16, 2021, 08:15:06 AM
Quote
- What is the actual difference between using the 500k pot and the 50? I understand it's "more resistance" but how is it effecting the original signal?
it depends, if its just in series with the input, wihtout going to ground, the 500k pot reduces the gain more, but they still have the same max gain.
if the lug is grounded, the 500k does a bit less loading on the guitar. when its on max, the input impedance of the fuzz face is low enough to ignore the pot value, but when you start to turn down, youll find a slight reduction in top-end with the 50k compared to the 500k, but it will probably be marginal.

Quote
- Are both the 50k and 500k when maxed letting in original signal or are they "boosting" it to their respective resistance? Like am I effecting the tone the same with both pots, just on a wider range? Or am I adding more gain with the bigger value?
all the pots do is take out gain, the 500k has a slightly different sweep and effect due to higher resistance compared to the 50k pot.

Quote
- With the 500k, It only really has in effect in the last 1/3 of a turn. Is there a way to just have that range of resistance spread out through the entire range of the pot? In other words, letting the user dial in a more precise tone.
make sure to try both log and lin pots, and the log pot in reverse. that gives 3 sweeps, and you can choose the best in your opinion.

cheers, Iain
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 16, 2021, 09:18:12 AM
Thank you for the thorough explanations and clarifying everything for me. Makes a lot of sense now

Quote
make sure to try both log and lin pots, and the log pot in reverse. that gives 3 sweeps, and you can choose the best in your opinion.

Yes, I'm just trying to find the best option. I want the full range of gain, without adding any at max (which you explained isn't the case).

Essentially trying find the most sweep for cleaning up gain. I've tried lin and log, but will have to try reverse.

I think the Lin had a more gradual sweep of the gain, where the log seemed abrupt. Want to make sure I'm not "missing" any of the sweet spots. That's where all the magic is for the FF in my opinion.

I guess I have to figure what is best value resistance to get the right amount of cleanup. 500k may be unnecessary.




Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: iainpunk on March 16, 2021, 10:35:08 AM
Quote
500k may be unnecessary.
i use 250k or 220k pots for fuzz face-based circuits, and i generally put a log in reverse (when you turn the control up, you turn the gain down) and call it "attenuate"

cheers,
Title: Re: 500k "guitar" volume pot on a Fuzz Face
Post by: DJPsychic on March 16, 2021, 01:40:08 PM
Will definitely have try that. I like the reverse idea, makes more sense aesthetically as well.