Fuzz Circuit Issues

[spaceace76]

I recently built up a fuzz I designed for a friend, based on the Bazz Fuss/Buzz Box. So far it doesn't produce sound, and I built twice. Once with my own PCB layout, and again on perf with everything socketed, with the same results both times.



I used non polarized 1µF caps in place of the 10µF's listed, and 390R's for R4,5,6.

So far the audio probe hasn't revealed anything, and neither have voltage or continuity tests. My guess at this point is that there is some major design flaw that I'm not seeing.

I'll post voltages tomorrow, and pictures if deemed necessary. Thanks for any help you guys can provide, I'm starting to pull my hair out over this thing

[sundgist]

Apart from the first, should the 10uF caps not be turned the other way?

[sundgist]

Apart from the first, should the 10uF caps not be turned the other way?

Sorry, just read your post properly re: using non polar caps.

But as far as the schem goes can anyone confirm which way the caps should face. Just for my peace of mind!

Does one stage on it's own produce any sound?

[Quackzed]

yeah, i think all the polarized caps need to be turned around...

[petemoore]

  the - side of the capacitor should never see a potential which is + compared to the capacitor + terminal [reverse polarization's no fun].
  For NPN Negative ground circuits:
  Often you'll notice the capacitor - is 'pointing' toward Gnd. [if not Gnd.d].
  Also the + side toward circuit [when DC blocking].
  - needs to be at a negative potential compared to + at all times.
  Some positions require non-polar = bipolar capacitence because polarity inversion takes place there.

[earthtonesaudio]

Remove (open circuit) R7 and see if that fixes it.

[spaceace76]

Sorry, just read your post properly re: using non polar caps.

yes the 10uF caps were NOT used. This version of the schem was drawn with some notes and tweaking ideas for myself. I don't know why I bothered to use polarized caps here as I never intended to have a value that high. I went with 1uF, non-polarized for all 4 caps.

Remove (open circuit) R7 and see if that fixes it.

I've tried that too, along with removing the diodes and flipping the transistors and I get the same results. No sound, and a bit of white noise that varies somewhat in volume when you turn the volume knob. Either the datasheet is incorrect about the pinout, or I'm just dense.

Does one stage on it's own produce any sound?

I was going to try that today. On the PCB build the audio probe never got any signal past the first capacitor. I could trace the signal past the switch, past the cap, but at the second cap (after the first gain stage) I got nothing. That lead me to think my pinout was wrong, so I double checked and it was correct. I even flipped it around just to be sure, and I get the same results. I'm also going to try some different devices, and the audio probe on the perf build.

Thanks for all your insight so far guys!

[Brymus]

>The audio probe never got sound past the first cap.
That sounds like your problem then,you should get some signal through the cap if its good and soldered properly.

[spaceace76]

no it gets through the cap, there just isn't any signal past the first gain stage.

i would advise folks to read my entire post, twice even, since i'm not so great at this writing business  

i just tried it through one gain stage, it had extremely low output, i had to crank the practice amp all the way up to even begin to hear it.

tried one stage with a 2n5088, this particular device has it's pins labeled, so theres no messing up here. still no sound from the transistor. double checked the battery, it still reads 9v, checked both cables im using, ground and 9v connections, etc

[Gus]

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Voltages at the collectors, bases and emitters and at other parts of the circuit should be step 1.

[spaceace76]

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Voltages at the collectors, bases and emitters and at other parts of the circuit should be step 1.

i was just about to post them when i discovered the 9v connection to the transistor was messed up. dunno what happened on the PCB build but this one works now!

thanks guys!

[petemoore]

  I hate that [in a purely sarcastic way !]...just when we're about to nail the problem down you go and get it fixed some other way...lol.
  Congratulations !
  I'm glad it's working and mean this post to be read only in only the funniest and happiest ways.

[stringsthings]

  I hate that [in a purely sarcastic way !]...just when we're about to nail the problem down you go and get it fixed some other way...lol.
  Congratulations !
  I'm glad it's working and mean this post to be read only in only the funniest and happiest ways.

no worries, mate .... to the OP :  it's always a good idea to check power .... over and over and over again  ....