Footswitchable Fuzz Face Input Pre Gain Pot help

[dwrockdoctor]

Hi all, it's been a while since I last posted. I have recently begun making fuzz pedals off of veroboard layouts and have successfully built my first bazz fuss.

I have now moved my sights to an NPN silicon fuzz face build on vero and was after some advice. I'm putting an 250K input pre-gain pot into the build as I did this with my dunlop JHF1 fuzz face and really liked this mod. This time I'm going to make as a normal pot to tweak whenever instead of a trimmer mounted to the circuit board.

What I was wondering is if it is possible (and easy) to make the input pre-gain pot footswitchable with a 2nd footswitch so it can be defeated. That way I could dial in a cleaned up fuzz with the input pot and be able to turn it off and switch to full on gnarly fuzzy goodness at the tap of a foot...

Here's the veroboard layout that I already edited with the added input pot mod (I think it is correct, let me know if it is off):



I tend to be more of a visual person so if it isn't too much to ask, if someone could take this image and draw in the required wiring to add a DPDT footswitch so I can switch the input pre-gain pot in and out of circuit that'd be great!

Any advice is welcome either way, thanks for your time guys

[Quackzed]

 

[dwrockdoctor]

Awesome, thank you, you sir, are a legend 

[GGBB]

If you are going to add a switch, you might as well add a third option for setting up the gain pot as a standard volume control like in Joe Gagan's Easy Face. See the yellow lines below and use a DPDT on-off-on switch. Gives you bypass, pre-gain, and volume on one switch.

[joegagan]

If you are going to add a switch, you might as well add a third option for setting up the gain pot as a standard volume control like in Joe Gagan's Easy Face. See the yellow lines below and use a DPDT on-off-on switch. Gives you bypass, pre-gain, and volume on one switch.

thanks for the mention!

you can even go one step further, open up your 250k and carefully sand the carbon away on the CW end til you get 0 ohms. like the no-load tone pots.

this way, it goes from full up to FULL UP.

i never really liked the way the clickswitch on CCW went full volume right after you turned the thing down. seemed weird.

[dwrockdoctor]

Great guys, thanks for all the options, it's much appreciated as I am a noob at all of this.

The only reason I thought of a second footswitch was because I am using a marshall style dual footswitch channel switch enclosure I had laying around for the fuzz face build and didn't want an empty hole where the second footswitch would be... that and I do love the fuzz face with controls maxed sound but use the fuzz face with guitar (or pre-gain) volume rolled back a bit much more, and only ever use maxed out settings for those real heavy riffs or freakout moments and it'd be great to footswitch that sound in.

I'll let you know how I go with this one, hopefully will be done within the next day or so.

[pinkjimiphoton]

hey bud, welcome to the forum. you MAY wanna think about adding some anti pop resistors in there too if ya don't wanna hear a loud click or pop in use..

if ya use a 3pdt, you can wire up and led/bicolour led too so ya know which "mode" your fuzz is in at a glance.

[dwrockdoctor]

Okay, trouble shoot time (kind of inevitable at some point)...

I hooked everything up and I am getting the fuzz effect sound with all controls and switches working, but at extremely quiet levels. I've double checked my wiring and veroboard placement to the vero layout I attached earlier and it all matches up fine. I found that if I touch my finger to certain parts of the solder points on the veroboard that the fuzz will get louder, though still much softer than the bypass sound, would this indicate a grounding issue?

Maybe it's time to get the DMM out...

[Quackzed]

did you do the yellow wire third option thing? that would be for a on-off-on switch, and might mess with the available output.

[GGBB]

did you do the yellow wire third option thing ... might mess with the available output.

Not really - works just like rolling back the guitar's volume control - cleans it up. Lowers the input level but that just results in less clipping not actually a lower output level. Unless of course you dial it way back so there's almost nothing going in.

[Quackzed]

true, i was looking at it if the pregain were dialed low, you'd get lowered input plus low resistance to ground at the input , but cranked up- no in line resistace , 250k to ground at the input wouldn't reduce volume very much...
... also a plus 1 to pop resistor on the input, as pinkjimi recommended, to help reduce pops when switching pregain on/off in the circuit, and also keep that input wire from floating and picking up radio static noise etc... just a 1Meg resistor from the tip to the ring of the input jack should do it... 

[induction]

... also a plus 1 to pop resistor on the input, as pinkjimi recommended, to help reduce pops when switching pregain on/off in the circuit, and also keep that input wire from floating and picking up radio static noise etc... just a 1Meg resistor from the tip to the ring of the input jack should do it... 

If it's on the input jack it will be out of the circuit in bypass, so the input wire will still be floating, and it won't do anything to prevent pops when engaging the pedal. Better to put it on the board.

[Quackzed]

  thats true, i think i was focused on the input wires acting like an antenna, so i wanted to put it on that input wire... but on the board makes more sense for an anti pop resistor...
and deal with any weird reception/ antennaish issues IF they show up. i've made a few fuzzes over the years, thats why i'm a bit worried about the input working as an antenna...   

[dwrockdoctor]

No, I didn't do the yellow wire hookup. I didn't have a DPDT switch handy for the pre-gain switch so used a 3PDT but I couldn't imagine that would cause any problems, I only had to use one column of the switch anyway.

I just had another poke around the solder joints and narrowed it down to when I touch the solder joint of the collector of Q2 is when the volume of the fuzz will get louder when I make contact with it...

Any particular reason for this phenomenon?

I'm using sockets for the transistors too (2N3904's). I think I'll whip out the soldering iron and at least resolder the joint to see if that helps.

[induction]

thats true, i think i was focused on the input wires acting like an antenna, so i wanted to put it on that input wire... but on the board makes more sense for an anti pop resistor...
and deal with any weird reception/ antennaish issues IF they show up. i've made a few fuzzes over the years, thats why i'm a bit worried about the input working as an antenna...   

A small cap from Q1 base to ground is supposed to be a good cure for RF noise.

[Brisance]

And I suggest start learning how to read schematics right away! That way you actually know what you are doing and forces to put tought into each circuit.