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I seem to remember people having trouble using the L7815 in some builds in the past, but I think the threads got nuked in the forum crash. I'd stick to LM7815. I probably have an extra I can send you if it helps.

[03.28.16]

03.28.16

Turnabout
- Based on the JHS Andy Timmons Sig.

Yeah good call - IC is wrong way in. It's possible it could have been damaged but in my experience it's probably fine. Flip it around, check your voltages on pin8 and 4 to make sure they are right.

Are you sure you have that DC Jack wired correctly? I can't tell from the angle of the pic. You won't be able to use that jack anyway - it will cause a short with the enclosure. Use plastic/insulated jacks for DC.

Can we see a pic of the build and wiring?

Here's what I am thinking for the tone control - you could put a cap and variable resistor to ground in parallel with C29 or C25 (after the expander). Maybe 10n and 10k. Or, perhaps something off pin7 of U1B. Those all seem to be likely candidates.

I have not built it with BAT41. It would work you might lose a little sensitivity in the attack/response of the compression but my guess is it's not going to be night and day difference. You could always use 1n34a or 1n270 if you have them. I just stayed away from them here because they are a bit tall. They might fit in the enclosure...I'm not positive. You might be able to solder them on the bottom side of the PCB, too.

Pretty sure 330n is right. It's on the trace schematic I have and if you look at gut shots of the SM, you'll see a huge Panasonic cap right around pin9 of the PT2399 which could only be that size.

Actually, reducing them would change the cut off of the multiple feedback filter and increase gain.

Are we sure C9 is 330n? 33n makes more sense to me... also seems like there should be a cap to ground from R3.

So looking at the schematic, the input goes through an MPF in to the PT2399 and then the wet output goes straight to the output unfiltered and the feedback (or dimension) goes through another filter using the other PT2399 opamp before being fed back in to the PT2399 input.

Anyway, increasing R9 should limit the feedback, if you increase R10 you're adjusting other stuff too.

Reducing R7 increases the gain of the MFF, but reducing R8 decreases the output at pin 14. My thinking here was series resistance at R10 was not giving the right result so let's have less output at LPF-2 (although it does change the whole thing). But, you are probably right - just leave everything as is and make R9 bigger. I should really etch this board and build it.

I'll have to double check on that 330n cap.

Well I don't know. But, it would reduce the gain of that output from the PT2399 which might help a lot. Or, not!

Might be better to reduce R7/R8 to 10k then.

Dude...cool! I will definitely give this a try. I have two...one stock and one I modified to use an expression pedal for the delay time. I think I'll put it on the second one. Was also thinking of putting in a filter control for some tone variations. I love the old PDS1002.

So, there's actually no pull-down resistor in the Harbinger. There is a biasing resistor for Q14, but that is on the opposite side of C28. There shouldn't be any DC on the input in either the Modern or Vintage mode to cause a pop esp. if you are wiring it to ground the effect input on bypass. But sometimes switches just pop despite what we think should happen It certainly won't hurt to try a pull-down to see if it eliminates the problem. Put a 1M resistor on your footswitch -it'll go from the FX input to ground.

I have not experienced a pop with the C/V switch, but again you can try another 1M or higher resistor there. Solder the resistor to the two outside legs of the SPDT switch.

At the same time, it wouldn't hurt to do a quick DC check with your multimeter. Specifically you would want to check R49 and lugs 1 and 3 of the CV switch for any DC voltage. That would indicate one or more leaky caps.

That's the correct pot. Looks like there is some extra text in the link in the doc which is making it not go to the right location. I'll fix that.

Check voltages, audio probe the input and output.