Klon replica from GGG, not passing signal directly?

[gbkd80]

I just finished my second build, a GGG Klon replica.  I pressed and etched the board as well. 



While I'm happy with how it "looks", it isn't functioning right.  It isn't passing signal without the knobs affecting the clean tone.  I did check all my wiring and it is correct based off the build instructions and following some pictures etc.  When the pedal is engaged, it does seem to work as intended.  But I can't understand why it won't pass clean signal unaffected by the pots... anyone else have similar issues with these or am I one of few?  LOL

[MrStab]

nice one, gbkd! that looks really neat and tidy, and it's cool that the actual effect works.

i haven't built the Klon, but i'd guess it's to do with the area around the 3PDT switch. the GGG layout diagram IS quite confusing, so much cross-referencing with the schematic is probably a good idea.

you should quadruple-check the 3PDT wiring itself. also, R26 and R27 seem to be permanently-connected to the output in the schematic, and either one is shorted to switch mode. are R26/27 definitely 68k? are R4 & R25 definitely 560 ohm? it's possible the "on" state is permanently-overpowering the bypassed state, possibly by too-low a value in one of those resistors. maybe that's BS though, and someone who's built the circuit will come in with a better suggestion.

also... why didn't they put R26-28 on the board?!! i'm sure there's a good reason, but it annoys me. lol

[Groovenut]

I cant tell from the pic, is there a connection between R31a-3 and R31b-2? Also verify that wire L isn't touching the resistor lead on the switch (looks too close to tell in the pic).

[gbkd80]

I cant tell from the pic, is there a connection between R31a-3 and R31b-2? Also verify that wire L isn't touching the resistor lead on the switch (looks too close to tell in the pic).

Yes, there's a lead going between the two.  It is hard to tell, I just used a clipped resistor lead.  The wires on the switch should not be touching; I actually thought I had them backwards at first and desoldered them but put them back when I realized it was right.  Issue was present from the beginning.  I'll double check though. 

[Groovenut]

also check to make sure both sides of the dual pot are good and functioning. I've found more than a few bad dual 100k pots.

[gbkd80]

also check to make sure both sides of the dual pot are good and functioning. I've found more than a few bad dual 100k pots.

You think that would affect the bypassed signal?  How would I test that the pot is working correctly?  It does do what it's meant to...

I actually de-soldered and re-wired the entire pedal and replaced the switch and it's doing the same exact thing.  The only difference with how I built this one is that I didn't do the kit, and I etched my own board...

[Groovenut]

If the bypass signal is being affected by the effect circuit, there has to be an issue with the clean signal chain, the grounding of the OD signal during bypass or both. Follow the trace from C1, R3, R4, R26 to make sure there are no bridges, correct components etc.
Also confirm that R13 D2 junction is grounded during bypass.

As for the dual pots, if the OD circuit appears to be working fine then the pots are good. I understood your statement in the OP to refer to the active circuit with the drive at zero as the "clean tone", rather than effect bypass.

[~arph]

There is a klon replica at GGG now? I need to visit that page again...

[gbkd80]

I decided to re-visit this one, since I hadn't resolved it and left it on the shelf until I was in the mood.  I thought I would at least mention that I took the voltages at the pins of the 3 ICs and everything checks out against the build instructions/troubleshooting. 

Here is a solder-side of the PCB for reference:





The switch really is wired correct, at least from the instructions and using the picture on their site as reference:



And yes, I do have C4 on my board, just can't see if because I had to use this huge sfacimme'n cap for C6 because that's all I had on hand.

Just to reiterate, the effect works when the circuit is active.  At least it sounds like I believe it should.  In BYPASS, the volume/tone/etc controls affect the bypass signal.  So, if I have the effect off and in bypass mode, and turn the volume of the effect down, it will turn down my bypass signal. 

i tried tracing some things out to make sure before I posted, and got the voltages etc.  But this one really baffles me..

[slashandburn]

This is a long shot and I'm probably barely "qualified" to be offering thoughts here but when you said you had built it twice with the same problems I got thinking of the offboard If you used the same switch, could it perhaps be the actual switch? Maybe it's not locking correctly in one direction and screwing up the bypass.

Edit: Bugger, sorry. I can now see different switches in the photos you've posted.

Ah I dunno,  good luck with it!

[gbkd80]

This is a long shot and I'm probably barely "qualified" to be offering thoughts here but when you said you had built it twice with the same problems I got thinking of the offboard If you used the same switch, could it perhaps be the actual switch? Maybe it's not locking correctly in one direction and screwing up the bypass.

Edit: Bugger, sorry. I can now see different switches in the photos you've posted.

Ah I dunno,  good luck with it!

The bottom photo isn't my build, that's the photo from the GGG site just for reference of the switch wiring.  But yes, I did change the switch originally because that was my first inclination...