Mangler REALLY thin and awful

[Zerstorte Zelle]

Hey all,

Trying to build a mangler with ac128's and failing hard. Couldn't get a 20k trimmer but popped a 50k in there. Biases right to 4.5v and everything. looks like I'm all wired up proper too. plug it in and the led lights and it passes audio but the knobs do very little, no fuzz at all and the sound is akin to quiet icepicks.

nothing like functional.

any thoughts?

ZZ

[gtr2]

are you positive you have the pins on the ac128's correct?

[Zerstorte Zelle]

I believe the pins are correct.

[jkokura]

Belief is not enough. You have to be positive. That's the first thing I would suspect too. Next would be no power to the transistors.

Jacob

[Zerstorte Zelle]

there are no markings on them noting b e or c. that being said they only pass audio oriented one way.

also... tried two different pairs. the third pair is working wonderfully in my zombii.

hope that helps. again any assist would be great.


zz

[add4]

I experienced the same kind of problem, along with a strong volume drop, when i put a 1n cap instead of a 100n in the signal path..
maybe check your cap values?

[mgwhit]

You're getting good advice from everyone (I'd put my money on add4's capacitor suggestion), but you'll get even better help if you can upload some high-resolution, in-focus, well-lit photos of your board.

[Zerstorte Zelle]

isn't c3 supposed to be a 10n  (what i used.) i'll check into it more this afternoon.

[Zerstorte Zelle]

just rewired the pots... reflowed all solder joints. same issue. thin...no fuzz, huge volume drop but passes audio.

should i be switching c3 to 100n? i don't get it.

zz

[JakeFuzz]

When I troubleshoot fuzz face circuits I always put in silicon transistors first to make sure it isn't the transistors acting all weird. I am not sure what kind of stockpile you have but you could stick some 2N3906's in there just to take the finicky nature of germanium out of the equation. I've had a few really bad germaniums that sound just like you are describing.

[cjkbug]

did you socket the transistors or solder them? ge transistors are very easy to cook. is there any excessive noise? what package type are the transistors. the european black glass ones have a red dot to locate the collector. the metal can types from the us usually have a tab denoting the emitter.

[mgwhit]

just rewired the pots... reflowed all solder joints. same issue. thin...no fuzz, huge volume drop but passes audio.

should i be switching c3 to 100n? i don't get it.

No need to switch C3 to 100n.  I think the point is just to confirm the 10n value of that component.  And while you're at it, triple check the value of every component (especially C2, C3, R1, R3 and R4).  Can't say it enough: photos help.

[Zerstorte Zelle]

Here are two photos, best i could get with my phone. for what it's worth i just had it plugged in with a booster slamming it and it sounds like that helps but not nearly enough. also the knobs do little to nothing and only really sound like anything maxed out.

[jkokura]

Your electrolytics are backwards.

Jacob

[cjkbug]

yeah they are! that will ruin your day.