T.M.K. (too many knobs)

[eerohei]

Hello,
i'm trying to get an effect working, its name is T.M.K or too many knobs, i found the schematic from http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html . I built it like it is on the schem, only difference that i was using TL072 instead of TL062. Has someone else tried to build this one? It's supposed to be a fuzz, which has controls for feedback, crossover distortion and octave blend for example. If someone here is well experienced with reading schematics, can you just check the schem out and write me if it's not a working one? Thanks a lot!
Eero[/img]

[Paul Marossy]

I haven't built this one myself, but I know that others here have built it from that schematic. All of Tim's circuits that I have built from that webpage have worked for me. You must have made a mistake somewhere...

[sir_modulus]

I havne't built it, and it seems like a easy build, so detect stupid mistakes (at midnight on an empty stomach 2N5033 looks a lot like 2N3055) The opamp might have a dif pinout and if it was just lying around somewhere, it might be damaged. Look for data sheets (type it in on google). Check that transistors are not damaged, and check all resistors for overheated ones, and see if any are blown. If a part is damaged, find out why (maybe too little resistance somewhere etc...) Check for bad wiring. That's all I can think of.

EDIT: Maybe it's like the Doctor Q, where only few opamps work in those conditions. Get a TL062 anyways (get one from small bear)

[Ge_Whiz]

Subbing the TL072 isn't going to be a problem here. Make sure, though, that you have the chip in the socket (You DID use a socket?) the right way round and check that you have numbered the pins correctly: down the left hand side 1-4 and up the RHS 5-8.

Otherwise, check the Vr supply and make sure that the three points intended to go to it do so and not to earth by mistake (my favourite error in circuits like this one). Each point should be +4.5V relative to ground.

As always, please tell us about how it "doesn't work". No sound at all? Quiet or gated? No effect?

[sir_modulus]

oh great....178 views (when i last checked). Tim's site is getting so much attention, that they shut it down for an hour

[eerohei]

thanks for everyone's input. The way this connection doesn't work: i get a sound out of the circuit, but it's only a bit duller and quieter than the straight signal from the bypass. I also tried it with an audio probe, and i could get a bit of fuzz like sound from between the diodes  (3 in the row) and very quiet fuzz from the pin 2 and 3 (if i remember right). And also we've been going through the schematic and the circuit, and it's 1 to 1 with the schematic... If anyone has this box or similar i would be interseted to buy... Thanks anyway for your help!

[aaronkessman]

do you happen to have the layout you used for this? did you PCB or perf build it?

[eerohei]

i used a pcb that i drew myself, i did it with a board that has the "film" on it. i can send you the layout and the board, but right now i´m travelling, so it takes few days...
Eero

[aaronkessman]

no, thats ok. I dont have board making supplies...thanks for the offer though.