Germanium Fuzz Face with resistor on output - possible noob question

[mr.adambeck]

Hey, I recently built a germanium fuzz face with "sino" transistors from Small Bear.

It sounds perfect through my little Vox practice amp, but through my Twin Reverb that I use in my band, it's a bit too trebley and has a brittle high end.  I messed around with some Low Pass Filters, but they all caused too much of a drop in volume.  I ended up putting a resistor in series after the output of the circuit and after trying out a few values, found one that knocked off just the right amount of treble.

As far as circuits go, I definitely don't know much about technical information, so I'm wondering if doing this would have any adverse effects that I haven't realized.  I assume it's lowering the impedence a bit and that's why it's less bright, but honestly I'm, not really sure if that's what is actually happening or not.  I don't know if having a lower impedence could cause problems that I just am too noob-y too realize or not, so I thought I'd ask the pro's on this forum.  Any help in understanding would be appreciated.

[John Lyons]

If it sounds good then it is good  
Yes, it is lowering the impedance.
No problem with that. You can also put
a capacitor in parallel with the collector resistor
of Q2 to cut down on some fizz.
Experiment to see what works for you.
Start with .001

John

[petemoore]

  It sounds perfect through my little Vox practice amp, but through my Twin Reverb that I use in my band, it's a bit too trebley and has a brittle high end.
  Sounds like a good example of how different amplifiers can be when reacting to say a FF, Twins are bright amps.
   I ended up putting a resistor in series after the output of the circuit and after trying out a few values, found one that knocked off just the right amount of treble.
  As far as circuits go, I definitely don't know much about technical information, so I'm wondering if doing this would have any adverse effects that I haven't realized.
  Mostly not, don't reverse power on polarized components, don't over-volt [exceed ratings] parts. The FF otherwise is a good circuit to learn some "whats does what". 
  I assume it's lowering the impedence a bit and that's why it's less bright, but honestly I'm, not really sure if that's what is actually happening or not.  I don't know if having a lower impedence could cause problems that I just am too noob-y too realize or not, so I thought I'd ask the pro's on this forum.  Any help in understanding would be appreciated.
 

[petemoore]

  Twins are bright..
  You can try some frequency shaping but that starts being a less pure FF and then..maybe some luck with a variable low pass filter could be wrought out through the Twin.
  Try maybe a different Fuzz pedal, Big Muff Pie has 2 clipping [distorter] stages [nice if the subject amp is very clean/will not contributing anything], and a tone control, and not that a Twin needs lots of boost, BMP has that too.
  Reports of Rat>Twin use are widespread, although not a double clipper, it has 3 controls.
  FF>Mu Amp>Buffer>Tone Control>Amp...
  Something to think about as more long-term project if you're inclined to tweek and experiment, FF>Mu is a pretty nice break-up tone [two distortion stages], that and some low impedance for tone shaping, it's no longer a FF but has interesting characteristics, some FF type tone and flexibility.
  @@Rate, distortion is the pre-distortion or 'internal box' distortion, making a Twin break-over just won't happen easily, nicely or go quietly, the voicing of course being critical to any Fuzz Box expected to make a clean amp sound distortey. 

[mr.adambeck]

Okay, so I think I'm going to keep the resistor, but I was thinking of wiring it to an SPDT as a sort of brightness switch.  Would I wire it like this?

[darron]

Okay, so I think I'm going to keep the resistor, but I was thinking of wiring it to an SPDT as a sort of brightness switch.  Would I wire it like this?

that would work. or this:


in the second diagram, the circuit is never broken. the switch just shorts out the resistor, making it 0 ohms - probably a slightly better idea. you could even use a spst swtich...

if you want to go with the resistor in series then a more functional idea would be to wire in a pot. turned all the way back it will still give you 0 ohms so won't effect the tone at all.

[mr.adambeck]

Yeah, I thought of having it in a pot, however, I already have 4 knobs on this thing and don't have any room left for another! 
Hence, the switch idea.  Thanks for the tip!