SOLVED 250 issues

[makethingsmakenoise]

Working on a Gray Spec 250. I've got bypass signal, my LED lights up, but no sound when activated. I've re-flowed my connections a few times and everything seems tidy.

One thing I'm realizing is that my board was a slightly different layout from the build docs (and other photos I've seen) – specifically the right side of the board with the clipping diodes and a few other components. I first noticed that because the diodes are facing the same way on my board. I'm building based on subbed parts provided by @pedalpcb at this thread and am wondering if that's throwing things off with my board being a slightly different layout. Or maybe a bad chip?

Any ideas? Please let me know if any other photos will help.

Thanks in advance for your help. This forum has been crazy helpful on nearly all of my builds.

 

[makethingsmakenoise]

One update: I pulled it out of the enclosure and got it all set up on my Auditorium. Same results, so I'm assuming it's something on the board.

 

[ICTRock]

Working on a Gray Spec 250. I've got bypass signal, my LED lights up, but no sound when activated. I've re-flowed my connections a few times and everything seems tidy.

One thing I'm realizing is that my board was a slightly different layout from the build docs (and other photos I've seen) – specifically the right side of the board with the clipping diodes and a few other components. I first noticed that because the diodes are facing the same way on my board. I'm building based on subbed parts provided by @pedalpcb at this thread and am wondering if that's throwing things off with my board being a slightly different layout. Or maybe a bad chip?

Any ideas? Please let me know if any other photos will help.

Thanks in advance for your help. This forum has been crazy helpful on nearly all of my builds.

C3 shouldn't be electrolytic. Replace that with a 47n film cap

 

[makethingsmakenoise]

Oh wow, yep that's it. Thanks!

 

[MichaelW]

That's what my board looks like, I haven't built it yet. Did the capacitor swap fix it?

 

[makethingsmakenoise]

@MichaelW It actually didn't, but now I'm questioning what else I might have put in the wrong spot. Re-checking all my parts now.

 

[MichaelW]

For one thing you have a 2n2 where there should a 1n. (See pic). I didn't look any further but that jumped out at me.
Edit: Actually the one next to the A10pot is also supposed to be a 1n, is the 2n2 a mod?

 

[Robert]

Whats the part number of your opamp?

 

[makethingsmakenoise]

@MichaelW yeah that's part of the "gray specs" mod

@PedalPCB UA741CP

 

[MichaelW]

@MichaelW yeah that's part of the "gray specs" mod

@PedalPCB UA741CP

Gotcha, ok makes sense. I don't know what the other gray spec mods are but just looking at the board I see 4x 1m resistors. It looks like you have 2 different values in the 4 spots. I'm assuming that's also part of the Gray Box Spec?

 

[makethingsmakenoise]

@MichaelW yep, I referenced this thread: https://forum.pedalpcb.com/threads/distortion-250-to-gray-specs.1013/

 

[MichaelW]

@MichaelW yep, I referenced this thread: https://forum.pedalpcb.com/threads/distortion-250-to-gray-specs.1013/

Cool! I bookmarked that thread for when I build mine. Watching this thread to see how you resolve your issue. (Thanks for blazing the trail)

 

[makethingsmakenoise]

SOLVED: I replaced my 1M resistor + 25p cap combo, just because it seemed a little janky (my first time adding a cap to a resistor). Must've been grounding out somewhere, because that fixed it. Sounds awesome!

 

[makethingsmakenoise]

@PedalPCB Out of curiosity, is there a difference with the diodes on the board layout I have? Noticing that they're facing the same way, while they are typically are opposite each other on most layouts.

 

[ICTRock]

@PedalPCB Out of curiosity, is there a difference with the diodes on the board layout I have? Noticing that they're facing the same way, while they are typically are opposite each other on most layouts.

You can answer this question yourself with the schematic and a continuity tester.