Break Street OD - how to wire for TBP?

[HamishR]

Just ordered a PCB for the breakstreet OD and noticed on the build guide that it uses a buffered bypass. If I want to wire it as TBP I guess I would wire it as I normally would for TBP but do I need to attach the eyelet marked "BP" ( I guess for bypass) to anything?

 

[Robert]

If you want to wire it True Bypass just follow one of the other wiring diagrams and ignore the BP pad altogether.

 

[zgrav]

looks like that the BP is just a buffered output that you can leave unwired if you use the standard TBP wiring.

 

[HamishR]

Cool! Thanks guys.

 

[HamishR]

Ok - So I just built this pedal. It took me a while to get to because I was building others first! I have built it exactly to speac and wired up the switch exactly as per every other Pedal PCB true bypass pedal I have built, ignoring the BP pad altogether and I get nothing. The LED lights, I get a bypassed signal when bypassed but absolutely nothing at all when engaged. And by nothing I mean no buzzing, no hiss - absolute silence.

When the pedal is bypassed I can touch the switch lugs with my finger and get the expected hum. When the pedal is engaged I get no hum whatsoever even if I touch the switch lugs, which leads me to think it's shorting out somewhere. I have inspected every single solder with a magnifying glass, reflowed a few which looked remotely dodgy but no response. I have no solder bridges, no dry joints, no missed connections and I tested the switch and it works.

Has this PCB been verified? I can't think what I could have done wrong! Of course I may have but I can't see it. Any clues?

 

[Robert]

I built one of these back when the PCB was first designed. I don't remember any quirks off the top of my head, but looking at the schematic I see one thing that has me curious... Can you reverse C8 and see if that does anything for you?

 

[HamishR]

Tried it. No difference at all.

 

[Robert]

Okay... rather than have you start pulling random components out of your board and risk damaging it, set it aside and let me see if I can get my hands on the one I built. It hasn't gone far so I might still be able to get it and take look.

If not, I'll put one together and see if I have any issues with it. I don't think any changes have been made to this board so I can't think of any reason it wouldn't work.

 

[HamishR]

Thanks! I can't think of why it won't work either. I hate to think it's some dumb thing I did wrong but I have checked and checked... What gets me is the absolute silence. No noises, no buzzing, nothing.

 

[filthmunster]

Bought a kit via Musikding (EU) and I have the exact same issue. Ok when bypassed (buffer works), dead silent when engaged... I get a very low voltage on pin 12 of the quad opamp nowhere near vref? Other pins (3, 10) give an ok of ˜4.38V. Checked all resistors and solder joints about 5 times now (double checked measured before soldering, by bom and by pcb and by color code)... Even tried different opamps to be sure...
(Now that checked again... is R8 correctly traced to Vref on the PCB? I get 0V...)

 

[Robert]

Lift the right end of R8 and solder it to the right end of R102. (marked in the pic below)

This is corrected in PCBs marked "Rev 2".