did i get this thing right? 555 fuzz

[pinkjimiphoton]

this is from the freestompboxes.org forum, looked interesting, and i had the parts...so i tried to do a vero layout prior to trying to build it...
first, the schematic :



then the layout i did...i'm a little confused by the schematic, did i get this right? my biggest question i guess is if the b+ going to pin 8 is supposed to come off the bottom of the second trimmer, or directly connected to the b+?



thanks in advance, and as always, peace!!!!!!!

[pinkjimiphoton]

sorry, noticed a blatant mistake on the last attempt at a layout...the jumper between b10 and i 11 shouldn't be there...

i THINK this is right:



one more dumb question...what is supposed to be adjusted to 1 volt? the entire b+? 

[pinkjimiphoton]

brain death strucketh, and hard last nite...sorry. one more try, i think i got it right this time??



here is the original thread:

http://www.....org/viewtopic.php?f=28&t=10843&p=140143#p140143

[earthtonesaudio]

Links to that forum is censored by this forum.

Here's one of my later replies in that thread:

I tried this circuit again with a different 555 and got different results.

With this second try, I could not get an audio output without doing two things:
a) adding resistance in series with the V+ pin
and
b) decreasing the voltage for the bias resistor on pin 4 to zero.

I was able to obtain nearly identical results with two different 555s by making these changes.

I used a pot to add the resistance in series with the V+, and did not measure the value, but I did measure the voltage at pin 8, about 2.3V.

I'd classify this circuit as still in the experimental phase. 

[pinkjimiphoton]

thanks, eta,
i had no idea that the other forum was censored here!!!!!!!!!!!!!!
my bad! just trying to get a working layout to go by, sorry if i stepped on anyone's toes.
i did read the later post, and will try the suggestions if i run into trouble. it seems like a cool idea, and i'm kinda tickled by the idea of using a clock
as a distortion pedal.

hoping i got the layout right at least finally? gonna mock it up today, see if i can get it working...will get back to you if i do. thanks for the reply, mate,much appreciated!
peace
jimi

[pinkjimiphoton]

welllllllp....don't try this one, folks...spent a whole day messing with it, no dice!!!!!!!!!!


arrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrgggggggggggggghhhhhhhhhhhhhhhhhhhhh

[earthtonesaudio]

I'll take another look at this one later tonight.  I have a stash of 555s from different years (maybe even different decades) and if I can't make them all work I'll pronounce this thing a fluke.

To be clear the changes I was describing in my later post include:

-100k input "bias" resistor goes to ground
-10k rheostat in series with V+, adjusted so that pin 8 gets 2-3V.
-I never tried the input buffer/gain stage transistor.  Mine consisted only of input cap, bias resistor, V+ rheostat, 555, output cap, and volume control.

[pinkjimiphoton]

thanks mate,
i tried the suggestions you made with voltage, etc...still no dice. it definitely passes some signal, but seemed a little lossy. couldn't get a usable fuzz out of it tho.
i did originally try the one with the input buffer...but could only get it to pass signal without the battery hooked up! so i think i screwed something up. i had built it on vero, so i figured it was time to take the plunge and bought a breadboard at radio shack, and tried it on that instead, used trimmers (100k) for the 100k resistors, but no dice.
i'll hit rat shack again, get the two kinds of 555's they offer (i bet it's like deadastronauts tiny trem, where only one of them would work of the two rs stocks) and try breadboarding it again tonite. appreciate the help!! the idea of making a clock into a fuzz is just cool, lol...
peace!

[earthtonesaudio]

Yep, I tried it with 4 different ICs.  Same results as you.  With tweaking it passes sound but no gain over unity (probably more like a 10dB loss), and certainly no fuzz. 
Sorry to say that this one DOES NOT WORK.

I don't have a good explanation for why I got it to work once, either.   


There are some other 555 projects for guitar, most notably among them probably the Uglyface.

[pinkjimiphoton]

thanks mate. i'll look at the ugly face.

still had fun messing with it. i haven't cursed like that in...well, minutes.

rock on!