DOD 250 trouble

[rankot]

I've just completed my DOD 250 build, but I have a problem I can't solve. It works as expected if I connect it to signal generator - it distorts, volume and gain pots work as expected.

BUT

when I connect it to amp and guitar, it's not working at all! I'm completely confused, tried to trace the signal and it comes into opamp input, but the output is silent. When I try the same with signal generator (.1V sine wave), it works fine again. I've checked cables, they're fine.

Ideas, anyone?

[MaxPower]

That schematic is a bit of a mess. There are better drawn versions available which might help find a possible wiring error. In any case, never had an issue with several 250 builds.

Is it missing a voltage reference? I can't tell. Usually around 4.5 volts for a 9 volt supply.

[MaxPower]

Oh, I guess the 22k resistors set the vref? I don't know what the issue may be.
http://beavisaudio.com/schematics/DOD-250-Overdrive-Schematic.htm

[rankot]

I have checked Vref, it is 4.5V. In my build, however, it is further stabilized with unused half of LM1458 with simple voltage follower.

[MaxPower]

I don't see anything wrong with the schematic so double check wiring and proper component values and orientation.

[mth5044]

Do you get clean signal when bypassed? Are you using the signal generator into the amp/does the amp work? Do you get different voltages on your IC with/without the amp and/or guitar plugged in? Did you wire the output jack backwards?

[Rob Strand]

Other than connection issues with the Jacks,  check your amp isn't putting out DC at the input socket.

[rankot]

I AM STUPID! (sometimes)

And I should definitely work this when tired! I've just said: "Let's take another look at this before I throw it into recycle bin" and tried to measure DC voltages on input (in case coupling cap is dead), then measured voltage on IC pins and - voila! - noticed something not expected. Then looked a little more thoroughly and noticed that I forgot to solder PTC (which is between ground net and DC jack negative pin). So pedal worked when connected to my signal generator and test amp (they share the same PS, so power ground was provided through signal line), and it wasn't able to work when connected to another amp or with that test amp with guitar.

PROBLEM SOLVED.

Now I have noticed something else, I've used B1M for Gain pot and it has some action at the very end, so I will try C500k or even C100k there.

[guitar.a]

Hi... I'm new to the forum and I absolutely don't know how to make a post or start a new topic... So I have to write here. I made a DoD 250 pedal, the gray version, which is not so relevant to my question. And the next question is, why is there a short circuit on the output jack?  :icon_redface:This happens when I build any DoD overdrive pedal, and 308, 250 any version. The part with the clipping diodes is very strange to me, and because of it, I get a short circuit. It happens when I turn the volume pot. No one has been able to help me so far, I connect everything nicely. Can any of you? Thank you. 

[rankot]

Hi... I'm new to the forum and I absolutely don't know how to make a post or start a new topic... So I have to write here. I made a DoD 250 pedal, the gray version, which is not so relevant to my question. And the next question is, why is there a short circuit on the output jack?  :icon_redface:This happens when I build any DoD overdrive pedal, and 308, 250 any version. The part with the clipping diodes is very strange to me, and because of it, I get a short circuit. It happens when I turn the volume pot. No one has been able to help me so far, I connect everything nicely. Can any of you? Thank you. 

How do you make short circuit? Could you please share a schematic and encircle the part you're talking about, together with the photo of your build?

[antonis]

https://www.diystompboxes.com/smfforum/index.php?topic=130620.0