My Concrete Jungle buffered bypass sucks

[Kroars]

Just finished a CJ build and while the pedal sounds pretty good, the buffered bypass not so much. All of a sudden my Rockerverb sounded a bit anemic and almost as if it lost its character. Unplug the pedal and it’s full bodied and crystal clear. The difference is subtle, but definitely noticeable.

I’m assuming the two transistors in the circuit are for an input and output buffer, similar to a TS. I didn’t have either the BC184C or the 2sc3198GR, so I first substituted the 184 for a 549C and the 3198 for a 2SC1815. That’s when I first noticed the issue. Then I tried a BC184LC (with the legs adjusted for pinout) for the 184C and an MPSA18 (again, legs adjusted for pinout) for the 3198. Same issue.

Seeing as the BC184C and BC184LC are very similar (aside from pinout), I’m guessing perhaps the problem is with the substitutions for the 2sc3198?

Curious if anyone has built this yet and if so, did you have a similar issue?

Hope everyone is well.

https://docs.pedalpcb.com/project/ConcreteJungle-PedalPCB.pdf

 

[Kroars]

I ordered a couple KTC3198’s. I’m guessing very few have built the Concrete Jungle. I’ll report back how they work, in case someone else builds one. I wonder what was used in the prototype.

 

[Kroars]

Update: Just threw in a KTC3198-GR for Q2, same problem. Wondering if it’s with Q1. It calls for a BC184c, which I don’t have. I’ve tried BC549C as well as BC184LC (pinout corrected) both of which sounded the same. Still have a nasty sounding bypass. It’s got to be the buffered bypass on this pedal, maybe that’s what it does? It’s almost like it dirties up my clean signal. Best way I can describe it is that it brings on a bit of static dirtiness, weak sounding. Take the pedal out of the chain and it’s crystal clear again.

 

[Kroars]

@Robert -Curious, with C3 and C4 (both 10UF) connected to each other. C3 is polarized, but C4 is non polarized. Are they both supposed to be there? Sorry, to bother you, I’m just trying to figure out why my bypassed signal doesn’t sound good.

There’s another layout up that only shows the 2 non polarized caps (C4 and C14 -maybe they just missed the 10UF polarized cap). Just seems strange to me to have them connecting, same value but one is polarized and the other is not. That could easily be my ignorance though.

Thanks for your time!

 

[Nostradoomus]

some amps just hate some pedals

 

[Kroars]

some amps just hate some pedals

I’ve definitely come across that over the years, you’re absolutely right. Although, I’ve never had a pedal alter the bypassed signal in such a negative manner. It’s really very strange. I’ve built dozens of pedals with input/output buffers and aside from the typical pickiness with other pedals in the chain, never have I come across one that sucks the life out of my clean signal and even add a bit of grit/static -I hesitate to call it breakup but it’s akin to it.

 

[Robert]

The buffer has a similar arrangement to the Cornish buffer, although it doesn't call for a non-polarized cap.

Do you by any chance have another pedal with a similar buffer you could try?

 

[Kroars]

The buffer has a similar arrangement to the Cornish buffer, although it doesn't call for a non-polarized cap.

Do you by any chance have another pedal with a similar buffer you could try?

View attachment 86358

I do, in fact. I actually built a stand alone Cornish buffer (your C-Buffer) and it sounds great. Built two of the Iron Forest side by side and the pedals sound fine, just not great when bypassed.

It there just one buffer on the output of the Iron Forest or is their an input buffer that’s part of the bypassed circuit as well? If I’m reading the schematic correctly, it looks like the bypass signal travels through both Q1 and Q2?