Why my reproduction of DOD 250 does not work?

[puretube]

Try a smaller, non polarized (non-electrolytic) cap to ground for the pot. (e.g. 100nF or larger).

[Ben N]

If you disconnect the clipping diodes, is the output of the circuit substantially louder than the input? If not, there is something wrong with your gain stage. If it is, and your clippers aren't clipping, maybe they aren't properly connected between the signal path and ground.

[duck_arse]

measure and post the DC voltages on the pins of the IC, please.

[niektb]

btw, I think you're diodes are pointing in the same direction

[pinkjimiphoton]

btw, I think you're diodes are pointing in the same direction

nah, that's a hard clipper. two opposite oriented diodes, one end to signal, one to ground. may look like they're in the same direction, but actually are antiphase cuz of the ground connection. one clips the positive, one clips the negative side of the wave.

[pinkjimiphoton]

try making the feedback resistor much bigger...500k-1meg

ditch the 1.2k resistor. or put it AFTER  the clipper.

right now, you have a simple preamp.
if you want distortion,  you need to crank up the gain (and add that 10 u cap) and add a volume to it at the end.

then you'll get a bit of dirt.

[GGBB]

no clipping, no distortion...

Does anything happen when you adjust the gain pot? (Which is connected backwards by the way - clockwise lowers gain.)

[rikk]

Thank you sooo much for all your answers, unfortunately the circuit continues to not work T_T

for puretube: now I have directed the + of the caps forward to the guitar +.

for niektb: the breadboard does not split the voltage (the voltage is 9 volt from the red to the blue line of the breadboard)

for puretube: I have checked every wired and all seems to be connected well (deep). I have changed the cap after the pot with a non polarized one (0.1uF).

for Ben N: if I disconnect the diodes when I play the guitar I don't ear any changes 

for duck_arse: the DC voltage on the pins 7 and 4 of the IC is 9 volt (as expected).

for niektb: The direction of the diodes is not wrong, but for completeness I tried to change the direction of one diode and the result is the same.

for GGBB: if I change the gain pot the sound makes louder but I don't obtain the desired result.

for pinkjimiphoton: I tried to remove the resistor and I changed the feedback resistor with a 500k one.

Sorry guys but nothing seems to work.....

I leave here the version with your suggestions applied.
Panoramic:


Detail1:


Detail2:


Maybe could I have connected the jacks in a wrong way? My mind is blowing...

[niektb]

that gray wire that goes from 4.5V to the signal path, shouldn't that be a >100k resistor?

edit: never mind, the divider resistors are 1Meg

[Mark Hammer]

I hope you realize that, bit by bit, addition by addition, you're recreating the Distortion+/DOD250.

[Fancy Lime]

I hope you realize that, bit by bit, addition by addition, you're recreating the Distortion+/DOD250.

Well, that's how this started, isn't it?
https://www.diystompboxes.com/smfforum/index.php?topic=129078.0#msg1245665
I understood this here thread to be an attempt to understand the 250 from the bottom up.

[antonis]

for duck_arse: the DC voltage on the pins 7 and 4 of the IC is 9 volt (as expected).

I'm not sure if duck-arse expected 9V on pin 4..

[antonis]

So, could some willing guy merge present thread with this one..??: https://www.diystompboxes.com/smfforum/index.php?topic=129086.0

[rikk]

for duck_arse: the DC voltage on the pins 7 and 4 of the IC is 9 volt (as expected).

I'm not sure if duck-arse expected 9V on pin 4..

I meant that the potential difference between 7 (+) and 4 (-) is 9V

[antonis]

Diode pair on your breadboard isn't a "pair"...
(unless that unidentified green item bridging 34 & 35 columns is a jumper..)

[rikk]

Diode pair on your breadboard isn't a "pair"...
(unless that unidentified green item bridging 34 & 35 columns is a jumper..)

That green item is a wire that connect the line 34 and 35, so it should be a pair.

[antonis]

So, what are the voltages on pin 2, 3 & 6..??

[puretube]

Guitar volume turned UP? (sorry, but sh*t happens ...)
But for antonis` DC measurements, it needs to be turned down. All the way.

[antonis]

It should be better with circuit idling..
(no input signal..)

[duck_arse]

for duck_arse: the DC voltage on the pins 7 and 4 of the IC is 9 volt (as expected).

I'm not sure if duck-arse expected 9V on pin 4..

I meant that the potential difference between 7 (+) and 4 (-) is 9V

duck_arse understood what was meant by 9V. but with an IC having 8 pins, we expect 8 voltage readings. and we don't want potential differences, we just want your black meter probe on ground/0V/earth, and the red probes and reads the pins. thank you for your attention (if applicable).