help w/ fuzz face mod switch wiring

[raycroft]

Hiya.  I finally fixed my Fuzz Face (the reason I got into electronics was because it was broken- I couldn't fix it; so I built the Rocket  )!  I am modding it some- everything's great-even better than I remember 10 years ago.  I replaced the input cap w/ a 47k , and socketed Q1 so I could put a 2N3906 in there (replacing the NKT275).  Sounds awesome!

My inquiry is;    I like the sound of BOTH transitors, and want the ability to switch between the 2.  I assume there is a way; probably have to run wires to a small daughter board.  I just can't get it into my brain how to make it work.  What switch?      For some reason, I think I don't wanna use a stomp-switch- the other kind instead. 

Anyone got a diagram for this?   

Thanks in advance!

[BaLaClavaAa]

I don't know much about wiring, but I think the switch you are thinking of is a toggle switch, and if you had more then 2 then a rotary.

[petemoore]

I replaced the input cap w/ a 47k ,
  And so no DC blocking input cap?
   and socketed Q1 so I could put a 2N3906 in there (replacing the NKT275).  Sounds awesome!
  Easy Face is a great circuit.
My inquiry is;    I like the sound of BOTH transitors, and want the ability to switch between the 2.
  Yes. Or consider building a 2nd FF..I would think the bias requirements might be such that simply switching transistors could throw bias off..a work around for that exists.
  I assume there is a way; probably have to run wires to a small daughter board.
  ...I'd start with an 8pin IC socket assigned so pins 1-4 carry Q1a, pins 5-8 for Q1b, and emitters common, a DPDT switch required, 3PDt for LED option. Perhaps add a tapering resistance to the collector of the transistor requiring the higher collector resistance to bias.
  I just can't get it into my brain how to make it work.  What switch?
  Look for the layout, gotta be some, or hope for a link-to to appear in this thread.   
  For some reason, I think I don't wanna use a stomp-switch- the other kind instead. 
  Re: Consider the layout 

[raycroft]

"And so no DC blocking input cap?"-
I didn't make myself clear; sorry-  my ff is the original dallas arbiter; about 10 years old.  No dc jack. 

...I'd start with an 8pin IC socket assigned so pins 1-4 carry Q1a, pins 5-8 for Q1b, and emitters common, a DPDT switch required, 3PDt for LED option. Perhaps add a tapering resistance to the collector of the transistor requiring the higher collector resistance to bias.
great reply- right over my head, kinda.  I'm still in the need-detailed-ggg-type-layout stage.  The Rocket was my first ground-up build; other than modding my ts-9, wah, and now fixing the Fuzz.  I do   have some IC sockets laying around.  The biasing part is still beyond me.  All I know is... It sounds great!!   I gotta look for a layout here... gotta be one somewhere; figured it'll take a while.    Thanks mucho!!!

[tungngruv]

Taken from Beavis Audio site:



Might want to put the bias pot on the outside of the box with this setup.

More great stuff here:

http://www.beavisaudio.com/

[raycroft]

dangit!   I knew I had seen this somewhere- just couldn't remember where; It's been awhile.  The answer to this post is on his site under "switches".  Great site, too;  awesome projects w/ good pics. 

Thanks.  I spend about 10 hours a day researching diy.  Guess it's information overload.  Now I've gotta find out which is the bias resistor  .   

I've been thinking about a green/red led to let me know which one is active.  Maybe too far ahead of myself.

[tungngruv]

Now I've gotta find out which is the bias resistor 

The bias resistor is the one coming off the collector of Q2. I would use a 10k linear pot.

[raycroft]

Awesome!    Thanks for the replies, all!!!!

[Dragonfly]

another way to do it...been in my gallery for years (to paraphrase Gus)

[dxm1]

"And so no DC blocking input cap?"-
I didn't make myself clear; sorry-  my ff is the original dallas arbiter; about 10 years old.  No dc jack.

I think Pete was pointing out that 'K' typically referes to a resistor value.  You were talking about the input CAP.  So, did you replace the input CAP with a 47 'uF' capacitor, or did you remove the DC blocking CAP and replace it with a 47K resistor?  No biggie, but the statement was kinda ambiguous...

[petemoore]

  Looks like Beavis is having layout and luck with common base assignment, I figured go for the emitter...try Beavis' or Dragonfly's method..switch all three leads.
  Yea, bias knob on top of the box is nice, indicator markings where the chosen voltages are hit might help, then when you switch to the 'other' one you can have a point at which you know what the voltage should be, then easier to adjust and decide the sounds from that fixed point.
  I was thinking figure out which one likes the smaller collector resistor to bias, then if that's smaller by much, attach a second, added resistor to the collector that likes a little more collector resistance to bias, right between the switch and transistor...ie only that transistor gets the extre resistance.
  There are a million ways to skin a mule and a 1000 FF's.
  Yea, 8 pin IC's with many pins secured is a solid fixture, I used to cut them in 2, but try not to, I like them better whole...I just wrap the circuit around them, sometimes lace a bit of it through the middle hole...see 'perfboard template' at Runoff Groove, practice drawing and checking layouts for errors / neatness, space Vs. compactness.

[raycroft]

I think Pete was pointing out that 'K' typically referes to a resistor value.      Thank you, dxm1, for clearing that up for me.  Yes, I replaced the cap w/ a cap-47uF.  Whoooops! 

I always try to not post one here-coz I don't know what I'm talking about even enough to ask what I want to know.  I'm always glad I did, though, because you all answer my questions that I didn't know to ask. 
Pete, I like your idea best- now I just gotta figure out how to do it!  I think it'd be better to just hit a switch and be ready to go, not have to also turn a knob.  Both valid, though, because There are a million ways to skin a mule and a 1000 FF's.


Thanks again!

[petemoore]

  Daughterboards....ughhh, that and an addendum switch thrown in...how big a box...
  By the time the wiring and daughterboard...might want to try a different FF or FF board.
  I'd go with the Rocket works now and sounds good.
  The next one is bound to fire a bit differently, especially if planned out that way.
  Dunno if you've started yet...
  FF testboard !
  You nearly have that now, socket tranny and in/out caps, make any resistor you wanna diddle with on the large side of what [say make 100k feedback resistor 150k or so, then put a resistance across the resistor to try smaller values there].
  I'd use 2x 8pin IC sockets, one for incap 'n Q1, second for Q2 and output cap.
  Oh you wanted the second transistor in your FF...@@rate.
  Use a trimpot for q2 collector resistor, actually I like a trimpot with stop resistor...collector>6k8>10k trimpot>output, because then 6k8 - 16k8 is the resistance range available with the pot, and the pot is more 'fine tune' instead of oversensative, take it easy on the trimpot !
  Skip socketting a wired cap, start large, use an additional series cap for that position [reduces sum capacitence], to try smaller values, can be put on a lift switch to restore the board input caps value.
  Bias after every Qswap, take notes..