GGG "Boutique Late 60’s Fuzz Face Version" confusion

[GilmourD]

OK, I'm just linking to the schematic rather than posting it here and marking what I'm talking about due to the permission refused notice in the PDF.

http://www.generalguitargadgets.com/pdf/ggg_ff5_sc_b69.pdf

OK, so my confusion is how the controls are labeled, especially compared to the Analog Man Sunface. The 50K pot labeled as R7 is labeled on the schematic as bias. However, isn't the 10K trimmer pot labeled R5T the bias adjustment and R7 is the input trimmer (basically the white trimpot in a Sunface)?

Or am I crazy?

[thermionix]

I believe "Boutique Late 60s" is a reference to the Fulltone '69.  But you're right, R7 isn't a bias adjustment.  Don't really know what to call it, it's just variable series resistance on the input.  I did the same on my Ge Fuzz Face, but I usually don't bother labeling anything.

[GilmourD]

I believe "Boutique Late 60s" is a reference to the Fulltone '69.  But you're right, R7 isn't a bias adjustment.  Don't really know what to call it, it's just variable series resistance on the input.  I did the same on my Ge Fuzz Face, but I usually don't bother labeling anything.

OK, good to know that I'm not going crazy... Or at least this isn't hte reason I'm going crazy. 

Dunno if you've ever seen the video That Pedal Show did with Analog Mike about the various Sunfaces, but R7 seems to me to be the white trimpot in his pedals that knocks a bit of signal down and cleans up the fuzz a tad, as if it were a preset rolled down volume setting on your guitar. Would you agree?

https://www.youtube.com/watch?v=GkCT0SDsqmE

[GilmourD]

So, instead of putting the contour control in the circuit I was thinking of getting a 10k pot and wiring that in instead of the 10K trimmer pot for R5T, like a Sundial control.

Part of me also wants to add an additional series resistor on a switch after R7 and mark it Single Coil and Humbucker, so that way I could add a fixed amount of resistance additional to the pot for hot humbuckers. Is that a good idea or am I thinking of this wrong?

[thermionix]

I believe "Boutique Late 60s" is a reference to the Fulltone '69.  But you're right, R7 isn't a bias adjustment.  Don't really know what to call it, it's just variable series resistance on the input.  I did the same on my Ge Fuzz Face, but I usually don't bother labeling anything.

OK, good to know that I'm not going crazy... Or at least this isn't hte reason I'm going crazy. 

Dunno if you've ever seen the video That Pedal Show did with Analog Mike about the various Sunfaces, but R7 seems to me to be the white trimpot in his pedals that knocks a bit of signal down and cleans up the fuzz a tad, as if it were a preset rolled down volume setting on your guitar. Would you agree?

https://www.youtube.com/watch?v=GkCT0SDsqmE

That's a little different, basically a volume pot at the beginning, a voltage divider instead of a variable resistor.  Many here call that a Pre-Gain control.

[thermionix]

So, instead of putting the contour control in the circuit I was thinking of getting a 10k pot and wiring that in instead of the 10K trimmer pot for R5T, like a Sundial control.

Part of me also wants to add an additional series resistor on a switch after R7 and mark it Single Coil and Humbucker, so that way I could add a fixed amount of resistance additional to the pot for hot humbuckers. Is that a good idea or am I thinking of this wrong?

If I understand you right, both ideas should work.  I'd highly recommend experimenting on a breadboard first.  For example, a 10k bias (sun dial) pot might have too much range, and make it hard to keep a usable setting.  Maybe a 1k pot and larger fixed resistor would be more handy, but I don't know.  As for the fixed resistance at the input, I only use mine above 0 ohms if I run another pedal into the fuzz, so basically never.

[GilmourD]

I believe "Boutique Late 60s" is a reference to the Fulltone '69.  But you're right, R7 isn't a bias adjustment.  Don't really know what to call it, it's just variable series resistance on the input.  I did the same on my Ge Fuzz Face, but I usually don't bother labeling anything.

OK, good to know that I'm not going crazy... Or at least this isn't hte reason I'm going crazy. 

Dunno if you've ever seen the video That Pedal Show did with Analog Mike about the various Sunfaces, but R7 seems to me to be the white trimpot in his pedals that knocks a bit of signal down and cleans up the fuzz a tad, as if it were a preset rolled down volume setting on your guitar. Would you agree?

https://www.youtube.com/watch?v=GkCT0SDsqmE

That's a little different, basically a volume pot at the beginning, a voltage divider instead of a variable resistor.  Many here call that a Pre-Gain control.

Is it an actual voltage divider, though? Wouldn't a voltage divider screw up the relationship with the fuzz and the volume control in the guitar? The way they were describing it inferred that it was adding resistance.

[GilmourD]

So, instead of putting the contour control in the circuit I was thinking of getting a 10k pot and wiring that in instead of the 10K trimmer pot for R5T, like a Sundial control.

Part of me also wants to add an additional series resistor on a switch after R7 and mark it Single Coil and Humbucker, so that way I could add a fixed amount of resistance additional to the pot for hot humbuckers. Is that a good idea or am I thinking of this wrong?

If I understand you right, both ideas should work.  I'd highly recommend experimenting on a breadboard first.  For example, a 10k bias (sun dial) pot might have too much range, and make it hard to keep a usable setting.  Maybe a 1k pot and larger fixed resistor would be more handy, but I don't know.  As for the fixed resistance at the input, I only use mine above 0 ohms if I run another pedal into the fuzz, so basically never.

The 10K pot figure was based on the trimmer that's already in the circuit. I know the fixed resistor that's in that spot in an original FF is 8.2K. Supposedly the Sunface has a 2.2K resistor and a 5K pot, which doesn't get to 8.2K, so the 10K was to give it more range above and below.

[PRR]

> The 50K pot labeled as R7 is labeled on the schematic as bias.

It sure is not electrical bias.

It might be "sonic bias", a resistor here will affect response and overload. On a fully-finished pedal "bias" may be as good a label as any. On a DIY, where builders will be fussing with electric bias, I agree it seems confusing.

There's really too many knobs here. But I guess it lets every user find a "unique" sound in their setup.

[thermionix]

Is it an actual voltage divider, though? Wouldn't a voltage divider screw up the relationship with the fuzz and the volume control in the guitar? The way they were describing it inferred that it was adding resistance.

Yeah it will load down the guitar signal at input, same as adding a second volume pot in the guitar.  The higher the pot value, the less it will load it down when turned all the way up.  I've never messed with it myself, but I assume it's useful for getting the effect of turning your guitar volume down, without turning your guitar volume down.  Or something like that.