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

[timd]

The ah-ha moment! I didn't even consider this. My original breadboard - and following build didn't include the cap. Well Petey and Vince...did you use the cap?

[timd]

Hmmmm....Looking back on this thread, I did notice that Vince had a problem before Dead Astronaut suggested the cap. Petey - it seems like its your turn to give input on the cap issue

[Vince_b]

Adding or removing the cap didn't make any difference for me so I don't think that this is the problem.

[timd]

kodiakklub - here is is 556 I'm using:

ST
NE556N

[timd]

So I got back on the breadboard and found the following:

My hand-drawn "professional" schematic shows pin 10 connected to V+.

- If you connect pin 9 to V+ it will heat up faster than Charlie Sheen in a room full of coke and hookers.

****the pin 10 to V+ is actually not needed!!!!!!

Those that wish to get this working - don't put the cap connecting pins 1 + 8 on the 386 chip. Disregard the connection of pin 10 to V+ on the 556. I actually got some cool oscillations of my new build of this circuit. I think I might be working on more 556 and 555 guitar pedal circuits soon!

[timd]

Vince - I'll get those voltages to you in 5.

[timd]

The voltages of the 556 chip in the circuit:

Pins:

1. 7.79
2. .03
3. 5.70
4. .31
5. .02
6. .04
7. .01
8. .03
9. .01
10. .31
11. 3.69
12. .02
13. .02
14. 8.55

[kodiakklub]

timd: seems you have the tex inst version of the 556. doesnt seem to be different electrically.

I changed my schematic and layout but i will BB it first before I post them again unless someone wants them.

[petey twofinger]

i did not use the cap on the 386 , i also disconnected voltage to pin 10 , and many other mods  .

result is the same , the second chip does not pass audio . or when you connect voltage it gets really hot , really fast .

there are several major issues with the original hand drawn layout .

i am done .

[Vince_b]

Hey Tim, sorry to tell you that but there is no way that this circuit can works. I've tried unconnecting pin 10 from V+ and it doesn't make any difference.
You should redraw the schematic using your working unit as a reference, there is probably more than one mistakes as it is right now.

[timd]

I just verified it against the working one, and it matches. I'll post pics of the board soon. I can't be of any more than that....

[birt]

it seems like you've found a way to burn the right part of your 556 to get a cool effect that still passes audio. the golden combination of circuit and IC. start selling those 'working' 556's timd :p

[timd]

Here are some pics of the final working build and working breadboard version:

[petey twofinger]

pin 4 off the 386 is shown feeding to ground in the hand drawing , in the pic is it feeding to the + rail of the breadboard or the ground ? very hard to see , actually its a toss up , but i am leaning towards ground because of what the 3rd photo reveals .

no 100r resistor between pin 5 and + rail on 386 , as mentioned .

the wire going from pin 8 to the 10 nf cap off of pin 2 on the 556 ...

in the hand drawing it feeds off the ground side of the cap to pin 8 , in the pic it is going to the chip side of the 10 nf cap .

in the hand drawing pin 9 of the 556 is shown  going to ground but also feeding a 10uf cap resistor pot "combo" , in the photo there does not appear to be a ground  off the cap , only off the resistor .

i dont see any of the pots in the photos which really puts a damper on further dowsing . also the second chip ID numbers are not visible .

the worst thing my kid does is something like back talk or smart off sometimes , if she ever gets busted for dealing or steals a car , this might be a good punishment . " your choice , grounded for 3 years or debug this circuit . "

[timd]

pin 4 off the 386 is shown feeding to ground in the hand drawing , in the pic is it feeding to the + rail of the breadboard or the ground ? very hard to see , actually its a toss up , but i am leaning towards ground because of what the 3rd photo reveals .
Ground - its an optical illusion. Look closely and you'll see it.

no 100r resistor between pin 5 and + rail on 386 , as mentioned .
The 100 r is optional
the wire going from pin 8 to the 10 nf cap off of pin 2 on the 556 ...
in the hand drawing it feeds off the ground side of the cap to pin 8 , in the pic it is going to the chip side of the 10 nf cap .
Pin 2 and 8 are connected to ground via the cap

in the hand drawing pin 9 of the 556 is shown  going to ground but also feeding a 10uf cap resistor pot "combo" , in the photo there does not appear to be a ground  off the cap , only off the resistor .
The resistor connects the 10uF cap to ground. The purple wire on the breadboard pic goes to output (or a A100K pot for volume control)

i dont see any of the pots in the photos which really puts a damper on further dowsing . also the second chip ID numbers are not visible .
ST NE556N

the worst thing my kid does is something like back talk or smart off sometimes , if she ever gets busted for dealing or steals a car , this might be a good punishment . " your choice , grounded for 3 years or debug this circuit . "

[timd]

Can anyone spot an issue with my schematic? I must need another set of eyes to look at it - It makes perfect sense to me, but people are having issues, which is not my intent. I just wanted to share my fun circuit....

[timd]

Any luck?

[Earthscum]

I've been lurking on this a little bit recently. Giving an extra eye tonight.

Hope you don't mind a schem from me... kodiakclub, you can revise yours if you like once things are squared away... never hurts to have 2 good schems floating around   Screw Google, screw every prog I have that doesn't have a freaking dual timer, and screw 'sudo'... no schem from me, sorry. So far all I can find is noted below... still checking it out.

One thing I spot right away (this is what I think Pete was pointing out) is that pin 8 in the 556 SHOULD be connected to pin 2 in the schems (that's the way it's actually wired in your working unit). That directly couples pin 2 and 8 and they are both AC coupled to ground. This could be the source of overheating.

I'll get back with more... if I get something cleared out of my board later, I'll try it out. I'll definitely give it a try by the end of the weekend.  

ETA: Pin 9 should not be tied to ground (it isn't in working unit pic). Think there was note somewhere of this.

[timd]

Yeah, the pin 2 and 8 thing might be the culprit. I'm just looking for someone to get this thing working...its kinda driving me nuts.

[Earthscum]

Ok... improvise. I just "corrected" kc's schem (labeled as "1983FuzzbyTimd.gif")