GGG Red Fuzz...substitutes for the LF351?

[skiraly017]

I have just about every op amp except a LF351. Has anyone used another one with success? Thanks.

[slacker]

I'd think any single or half a dual opamp would work fine.

[jrc4558]

TL071 (also 061, 081, 021), LM741, NE5334, LF411, any single op-amp, pretty much. But choose one that has FET input.

[mac]

Before building mine I tried the TL071. It works ok. But I did not compared to the LF351 so as to tell if the are sonic differences. Use a socket and if you get a LF351 later you can replace it.

BTW, nice pedal. I use it just to colorize the dirt channel a little. An alternative to the TS. One mod I'd do to it is changing the tone pot with a lower value, 50 to 25K, and/or reducing a little the 3.3nF to gnd, maybe 2.2 to 1nF.

mac

[Crawf]

Before building mine I tried the TL071. It works ok. But I did not compared to the LF351 so as to tell if the are sonic differences. Use a socket and if you get a LF351 later you can replace it.

BTW, nice pedal. I use it just to colorize the dirt channel a little. An alternative to the TS. One mod I'd do to it is changing the tone pot with a lower value, 50 to 25K, and/or reducing a little the 3.3nF to gnd, maybe 2.2 to 1nF.

mac

Hi, I have a Red Fuzz which i built and have gigged it twice and must say was very pleased with it, what effect would your suggested mods have on the pedal and could a bit more gain/drive be squeezed out of it? cheers Crawf.

[skiraly017]

Thanks for the suggestions. I think I've found one that will work.

[mac]

First, the tone pot should be reverse log if you want the treble CW and bass CCW. Also once the resistance of the pot is increased a little the treble response falls quickly. Since reverse log are not easy to find a linear pot could be on solution, unless you do not care using a log pot having the treble CCW.
A linear pot about 25-50k does not fall as fast as a log pot from the max setting, ie CW. Ans as the treble response decreases in the first 10-20k, a 25-50k pot gives you more control.
The 3.3nF cap shunts some high freq to gnd, so reducing it a little makes the RF more brilliant.
IMO, a 50k-B and a 2.2nF is fine. But it depends on your amp also.

mac

[skiraly017]

Surprisingly I had a C50K on hand. It does offer a little more control over the tone shaping but I'm not sure it is enough to run out and buy one. Dropping from a .0033uF to a .0022uF thinned the tone out too much for my taste. I did however swap out to yellow LED's and preferred them to the red. The yellows cut down on the max amount of gain by a hair but seemed to offer a smoothness during decay that the reds did not have.

Of course I could be imagining this.