My new circuit - "1983 Fuzz" Old School Atari type fuzz

[Vince_b]

I tried different ones, but they are all from the same source.
Can you give me the voltages on the different pins of the ICs, it might help me to find what I'm doing wrong.

[kodiakklub]

updated with pull down resist and led resist

[petey twofinger]

has anyone built this off the diagrams yet ?

i really want to try , but , i am a lil nervous ,  vince didnt get it going ....

is the hand drawn diagram correct tim ?

[timd]

Yes, the hand drawn one is correct. Unfortunatley, I haven't heard from anyone else who had success. Petey - try it on a breadboard and let me know. Should be very quick and easy.

[petey twofinger]

i plan to , should be tomorrow , but some days i just cant get motivated (back injury) . 99 percent sure i still have a 556 ...

[petey twofinger]

didnt have a 556 , so my ole lady;s pickin one up for me tomorow .

[timd]

Hmmm.... that's a great idea - I'll have to have my lady start sourcing IC's for me too!

[petey twofinger]

eat shack is on the way home from her work ...

i got the ic , all the parts together , hopefully i will feel up to some work soon .

[timd]

Please let me know how it goes!

[petey twofinger]

it didnt go very well , as a matter of fact i had the same results as vince , the 556 chip got hotter than heck !

i kinda figured something was up when i really looked at the drawing so i didnt hook up the v plus connection on the 556 on pins 14 and ten .

when i did , my hunch paid off with a sizzled fingertip !

come on tim , i only have a few of those left to go around !

the front end was passing audio , loud and clear , the lil monkeying i did with the layout on the 556 did not pay off . looking at the circuit , i am scratching my head , cause i rebuilt it 3 times , in different "configs" w/the same results .

[kodiakklub]

oh now im super curious. gonna have to breadboard it today......

[kodiakklub]

looking at the datasheet and your original handdrawn schem, you have what i assume is 9V going to pins 14 and 10 of the 556. the max Voltage for pin 10 (reset) is 1V. timd: your drawing cant  be correct. can you please check your circuit again? thanks a million. i really want to get this thing sussed out

[petey twofinger]

+1 ^ !

[kodiakklub]

hmmm now reading this site: http://www.kpsec.freeuk.com/555timer.htm
it says that if one is not using the reset function, then it should be connected to VCC, ie. pin 14 and 10 joined as timd drew. totally confused as to why that makes sense electrically.

[kodiakklub]

petey: try disconnecting pin 10 and leave it NC. also try putting a 1k resist in series with the 100k pot going to pins 12/13. pin 12 is supposed to always have at least a 1K in front of it. i wonder if thats burning it up too?

[petey twofinger]

will do , busy now , brb soon ... oh and thanks !

[timd]

Hey everyone - I feel bad that everyone is having issues with the circuit. I'm not home now, but hopefully in the next day or so, I can work this out.
I would go with kodiaklub's suggestion of leaving pin 10 NC. You DO need power to pin 14.

Could the 556 timers I use have a higher voltage tolerance??? I was under the impression that they were all the same. 

[kodiakklub]

the voltage on pin 14 can be as high as i think 16v so we should all be square there. maybe time to investigate the current and/or voltage coming off pin 5 of the 386. ill start looking at that.
timd: can you tell us all the numbers that are on your 556 so we can find out the exact specs of yours? thanks.

[timd]

Will do - I'll be home tonight. I suspect the issue is with the V+ going to pin 10.

[kodiakklub]

my new hunch and now what i feel is the most likely culprit. tim originally (and assuming still) didnt put a cap between pins 1 and 8 of the 386. without a cap, the gain of the 386 is only 20. if you put a cap in between 1 and 8, the gain jumps over the moon to 200. pumping too much voltage or current into the 556. petey: did you add that cap on your breadboard? if not, then im stumped, but if you did, remove it and see what happens. if tim built exactly what his original schem is, then that cap is the only thing that changed.