Colorsound Fuzzwah (fuzz section) - voltages please........Dragonfly?

[frequencycentral]

I built the fuzz section of the Colorsound Fuzzwah but I'm finding it really quiet. The bypassed signal is louder. I've gone wrong somewhere.

I built it with a 100K pot for volume. Added a tone control to tame the highs - 47n cap to ground via a 100K pot - this is now disconnected while I debug.

Can anyone provide me with correct voltages?

I've tried it with the following trannies:

BC107
Bc547
2N2369

........with no real differance.

Thanks!

It LOOKS good though!

[frequencycentral]

Here's my voltages, BC547's in place at the moment:

Q1

C: 1.682 v
B: 0.985 v
E: 0.00 v

Q2

C: 1.018 v
B: 1.68 v
E: 0.993 v

Power supply is reading 9.11 v

This is the schematic I worked from:



Such a simple circuit compared to others I've built!

[petemoore]

Q1

C: 1.682 v This is about right
B: 0.985 v  At least a diode drop above emitter, looks ok.
E: 0.00 v  Gnd. is precisely 0.00v ok...
  Everything looks ok
Q2
C: 1.018 v That 8k2 might need adjusted.
B: 1.68 v
E: 0.993 v
  The resistor the 8k2 nodes to Is 100ohms.
  Could be the collector resistor needs to be adjusted.
  Something is pulling the collector V down or not pulling it up, Start at V+, and work your way through the resistors [measuring them] to the Q2 collector.
  Measure resistance between Q2 collector and Gnd. [wherever or everywhere else, looking for a trace which could pull voltage toward Gnd [less likely.
  Orientation of transistor 'ocourse.

[frequencycentral]

Thanks Pete. After scraping between the tracks I'm reading:

Q1

C: 1.271     
B: 0.588
E: 0.00

Q2

C: 3.03
B: 1.271
E: 0.646

So the Q2 collector voltage has gone up, but..............it still seems quiet.................anyone?

[PurpleStrat]

Have you tried increasing the 100ohm resistor?

[frequencycentral]

Have you tried increasing the 100ohm resistor?

No I haven't - yet. That would maeke it closer to a Fuzzface - 330ohm if I remember rightly. Hmmm!

[frequencycentral]

However - what I am getting is an awesome and very loud fuzz if I take the output directly from Q2's collector.........might just go with that!

[frequencycentral]

Ok - debugged. I changed out the 100 ohm for a 470 ohm. Loads more volume.

I found it to be pretty hissy, which I cured by taking a 33n cap to ground from the conjuction of Q1's collector and Q2's base. This also had an interesting side effect - you know how when using a FF the tone control on your guitar works in reverse - well adding that cap made it work the right way. I don't understand why - I just poke about until stuff changes.

My tone control onboard the pedal is less successful - a 47n cap and a 100K pot to ground at the output. I tried some different cap values with no real treble cut which I was hoping for. May have to experiment there! Any suggestions?

I'm back to a 2N2369 for Q1 and a BC107 for Q2.

....................and the Hawkwind album cover is on the pedal cos the Fuzzwah was a Dave Brock favourite at that time!

[PurpleStrat]

Try lowering the resister on Q2.

[frequencycentral]

Try lowering the resister on Q2.

I'll try it tomorrow! Will probably parallel another 8k2.

Thanks!

[frequencycentral]

Still having problems with this build - its way quieter than any other fuzz/overdrive/distortion I have, and the tone control I tried does very little.

My idea is to add the last part of a Big Muff to the circuit, to give a useable tone control and boost the volume a little.

Any thoughts, ideas, advice? Thanks!

[petemoore]

  I'd keep working on getting what you have there go loud like a Fuzz first.