zombii Issues

[teknoman2]

I just finished madbeans zoombiiand I am facing some issues. I test it with my rig tester and I have signal but the sound isnt the excepting one so :

1) I connect the pots facing down like 321. is this correct?

2)Also  R4 and Gate lung 3 are on the ground?

I use DMM and they are on the ground but the solder connection doesnt touch the ground.

3) My voltages with Stab at maximum  on Q1 are 1.14/0.62/0, on Q2 are 8.90/8.98/8.60

and on Q3 8.90/8.60/8.90. Are they correct?

4) Finally I have a lot of humming.

I am posting some photos as well.

Thanx on advance.

[teknoman2]

Anyone can verify zombi's voltages??

[Loztboy]

What kind of sound do you get?
Have you tried reversing the transistors?
The Zombi can sound crazy and unfortunate at some knob settings

[teknoman2]

I have some crazy oscillating sound and humming. (Probably because is out of the box)

I have put the trannies as madbean's shows on the pdf.

I reversed them and I didn't have any sound so the trannies orientation is correct I believe.

Also the Stab pot (lung 3)  is 9v on maximum and 0v on minimum so there isn't any pot issue.

Do you think my voltages are off?

[Loztboy]

Crazy oscillating an hum is perfectly normal on some settings. try putting everything on full except volume, you should then get some fuzz/distortion sound. (If I remember correctly.)
I'm not sure about the voltages, sorry.

[teknoman2]

Should I ground output sleeve to limit the oscillation when zombbi isn't engaged?

[Loztboy]

Out of box, you have to ground both input and output.
When in a metal/aluminium box you don't have to wire ground to the output, since the box will be ground.

[teknoman2]

I use Jacob's test rig when is out of the box

http://www.madbeanpedals.com/forum/index.php?topic=1140.0

so both input and output are grounded.

I mean that, if I ground output sleeve as well the humming and the oscillating effect will decrease

when I finally put it inside the box?

[Loztboy]

I never tested mine outside the box, I'm a box it before you rock it person (sux some times)
I think it will be more silent when you box it.
My first fuzzfactory (a musikding.de PCB) did bleed some when in bypass at extreme gain settings, but I think that was a result of too much spaghetti wiring.

[teknoman2]

Can you measure your transistor voltages with stability on max

so we can compare them? that would be very helpfull mate.

If not it's ok.

I believe Stability pot is a bias pot and when is on max (9v measuring the pot )

should the transistor collector must have 9v or 4.5v like big muff ?

[chromesphere]

Hi teknoman2,
Im not sure about the voltages but i can also confirm that when the you turn the stab ("stability") knob from full, back to zero, the effect will oscillate like mad.  Thats part of the joys of the fuzz factory.
Cant say why it ocillates when in bypass though. It might be somethign to do with your test box, or a wiring problem.

Also for the potentiometer pinout, they are numbered like this:
http://www.aronnelson.com/gallery/main.php/v/Brymus/Schematics/pots-pinout.jpg.html
Wiring them up backwards wont cause problems.  The potentiometer will just dial backwards.
hope that helps!
Paul

[teknoman2]

thanx Paul for the quick feedback,

I believe that the pots don't have any issues as you can see on the photos

I have put them like madbean's stadar wiring diagram.

If I put Stab to max I have 9v on the lugs and on min I have 0v so I believe they are correct.

The Stab is like a Bias knob controlling the dc current to the entire circuit.

Do you think that if I ground output sleeve as well on the 3PDT the humming will decrease??

Also do you think that if I use RCA cable to wire input and output the humming will decrease?

[teknoman2]

Yesterday I made a huge mistake I connect a bipolar power supply and I noticed smoke

on the circuit.

Now I am measuring the circuit again using the DMM ,

and the ground shows me 5v instead of 0v.

Do you think that something is burnt?

[chromesphere]

Smoke coming from the circuit?  Thats bad.  Somethings blown.  Probably a cap.  Maybe even, and hears the part you dont want to hear, the transistors.  Might explain why your having issues. Check all the caps for physical damage. You might want to consider just replacing them.  Theres only a few on this circuit.

I'm not sure if i'm reading your messages properly, but did you test the circuit externally from the enclosure?  If you didnt, i would rip it out and get it working properly first.  Then you can just solder the 4 wires back in again (in out ground +9v) when its working correctly.

Lastly, my stab pot is...well...stable, when its cranked fully to the right.  There is no oscillation.  When i crank it back, approx 1/4, it starts to make those crazy noises.  That, i believe, is the normal operation of the stab pot.  Might vary a little, but thats the general idea i believe.
Paul

[BraindeadAudio]

Not uncommong to get faulty germanium transistors. Very testy little things.  Ive made a few of these and no one sounds alike. Test your transistors HFE if you have a multimeter that lets you do that.