fuzz factory clone signal dies out.

[Vincentdndn]

So I build myself a fuzz factory clone with AC128 germanium transistors. It is quite an easy build so I thaught why not.
Now the problem is that when I turn on the effect the output volume is really low and the signal dies out after about halve a second.
I already checked al the connections but could not find anything that is wrong or broken.
Now I'm thinking it could be the capaciters, maybe they are bad but I don't have a capacitance meter.
Should I just buy some new capaciters or could it be something else?

thanks in advance,

Vincent

[duck_arse]

hello and welcome, vincent.

first things first, you need to go here and follow the steps:

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

then come back with those results, and the circuit diagram (or a link to) you are using. have a layout diagram handy for if we ask, and some photos of your build. then it will be a breeze .....

[Vincentdndn]

here it comes

1. fuzz factory
2. http://imgur.com/a/Y871n (not mine)
3. I followed the perfboard layout as he did. https://drive.google.com/file/d/0B8QZME8Plf4BdlVBcDA5WlRkeXB2aU5kVHdXTUtOREpFNDkw/view?usp=sharing
4. I could not find ac 132 transistors so I used ac 128 instead and yes i checked the pin lay out.
5. It is a negative ground lay out.
6. It makes a harsh distorted sound when strung hard but it dies out after about halve a second. True bypass works. It also drained a battery down in a few days.

Q1
c= 0V
b= 8,8V
e= 8,8V

Q2
c= 0V
b= 8,8V
e= 8,8V

Q3
c= 8,3V
b= 8,7V
e= 8,9V

C1
+=8,15
-=7,2

C2
+= 8,9
-=8,9

C3
+= 8,9
-= 8,6

C4
+=8,9
-=8,6

[duck_arse]

well, here is a schem of the fuzz factory:


when I look at the layout you linked to, I can see some hiding cuts on the vero which, if you made those cuts, would have a number of parts connecting to nothing. that is why we need to see YOUR work, not the other guys. he says his works.

there is something very wrong with your transistor voltages. you might also head over to geofex and read the technology of the fuzz face, if you haven't already.

[anotherjim]

If it is to that scheme - something really doesn't add up. There is 0v on Q1 collector.. A negative ground circuit should have close to 9v there.

[duck_arse]

I think his bad layout has Q3 as the 2n3904.

[anotherjim]

Oh, then it still don't add up. Q3 (3904) emitter is tied to ground on the layout.
Hmmm, not the good old reversed power supply gremlin d'yer think?

[Vincentdndn]

Ehm, what is the reversed power supply gremlin? Thanks for the help!

[anotherjim]

You've either got the DC supply polarity crossed or your meter leads were the wrong way around or on the wrong circuit terminal when you took those measurements (or both). Really easy to do. Getting the power supply crossed is easy to do too if you've been working on Positive ground circuits previously.

Did you have your negative meter lead on the 0volt (ground) of the circuit when you measured? Look at the circuit or strip board layout, Q3 emitter is connected directly to ground -  there should be 0.00 reading there on the meter. Getting nearly 9 volts on the Q3 emitter probably means that your meter negative was on the supply negative, but the circuit ground is actually connected to the positive supply.

First, measure volts across power supply (battery or 2.1mm DC jack). Second, keep the negative meter lead on the power supply negative and test for same voltage with the positive lead on the first part of the circuit it feeds  - the 5k "Stab" control in this case. Keep the positive lead there then place the negative lead on the negative power of the board - that's the connection with the 2N3904 emitter.
All the above readings should be similar. Make sure you don't have a negative (-) polarity indication on the meter reading for any of them.

Then test all your transistor voltages with the negative lead  at any of the last 3 places used above (you have proven that ground actually is negative ground now)

[Vincentdndn]

Ok, I looked at the diagram again and saw that I was missing the ground wire. So Q3 is now 0.00 V but it didn't fix the problem.

EDIT:
It still doesn't work properly but when I turn on the effect the signal comes out a bit compressed and at a lower volume. Any suggestions?

Thanks