Custom build question - need a trained eye

MBFX

Well-known member
Good afternoon, everyone! I have built 10 PedalPCB projects so far, and I decided to start trying out my own circuits and modifications on breadboard. Solderable breadboard seemed like a great way to begin going from breadboard to permanent installation, and I got some 1/4 size Electrocookie solderable breadboards for a few dollars on Amazon and got started.

My first build, a Fuzz Face, was rotated 90° because I am a fool and it didn't work. My second build, another Fuzz Face, worked first try! I socketed the transistors, used a trimpot for a bias resistor, and had hours of fun playing with my creation. My third build, an LPB-1, should have been a breeze! However, I wired it all up on the Electrocookie breadboard, connected it to my PedalPCB auditorium, and it didn't work.

I assume there are three problems: first, I don't have power rails on my solderable breadboards, and so I have to make my own and be really good at following the schematic and making sure what is on the breadboard is the same as on the solderable board. Second, I am trying to use as little space as possible so I can build another circuit on the same board using this circuit as a first gain stage, and I am probably misdirecting current somewhere. Third, I still don't REALLY understand what is happening in the circuit, so I am probably missing something obvious.

Here is the schematic I am using for the LPB-1 build:

1695753730785.png
And here is how I have translated that to the solderless breadboard:

1695754052888.jpeg


Can anyone see an obvious problem with my circuit? I spent hours looking at it, reading about signal flow to make sure the schematic wasn't wrong, examined my soldered circuit to see if it matched my drawing, and I can't figure it out! There are some components sharing holes for the sake of compactness - is that a problem?
 
This is the breadboard layout I copied, btw:

1695756558765.png

I received an email saying that there was a reply to my post, but I don't see the reply. The post said the problem might be with the voltage divider (R1 and R3) being in series. I honestly thought that was kindof weird, but I don't understand this stuff well enough to question it. Comparing my drawing with the layout above, I am pretty sure I coped it exactly... Input goes to one leg of the capacitor. The other leg goes to the base of Q1 on the opposite side of the input, and the voltage divider on the same side of the input.
 
Have a look at this thread. I used it to build my first breadboard pedal and it worked first time.

 
Screenshot 2023-09-26 at 4.05.35 PM.png

Check your transistor orientation. If you're sticking in your BC108 like it's oriented in this picture, I think the C and E would be swapped. What side is the little tab? It should be near the E.
 
Phil - I have it working on a breadboard; the problem is translating the circuit to a space-saving permanent design that happens to be on a solderable breadboard

spi - CBE are marked where the legs should go rather than what the transistor legs are; the transistor is definitely oriented correctly. Checked that a million times thinking I must have missed it, but the tag is on the emitter side. Unless I have a defective one with the tag on the collector, that's not the issue.

I'll double check my soldering when I get home. Maybe I have something on the wrong rail, or a cold joint, or I missed a joint.
 
Phil - I have it working on a breadboard; the problem is translating the circuit to a space-saving permanent design that happens to be on a solderable breadboard

spi - CBE are marked where the legs should go rather than what the transistor legs are; the transistor is definitely oriented correctly. Checked that a million times thinking I must have missed it, but the tag is on the emitter side. Unless I have a defective one with the tag on the collector, that's not the issue.

I'll double check my soldering when I get home. Maybe I have something on the wrong rail, or a cold joint, or I missed a joint.
Want to make sure I understand. You breadboarded this. It works. You then populated a solderable breadboard, w/same layout as your conventional breadboard. The soldered one does not work.

If that’s correct, please give us pics of both sodes of the board and off-board components. I’m sure at least a few folks would help you look for issues.
 
Want to make sure I understand. You breadboarded this. It works. You then populated a solderable breadboard, w/same layout as your conventional breadboard. The soldered one does not work.

If that’s correct, please give us pics of both sodes of the board and off-board components. I’m sure at least a few folks would help you look for issues.
No, the layout is different on the solderable breadboard. There are no power rails, and I have made things more compact. I was concerned I screwed something up while routing the power, because that's the biggest change besides eliminating a few jumpers. That's what the graph paper drawing is - each cell is a hole on the solderable breadboard, with the components populated. It seems like the drawing is at least correct, so I probably have a suspect solder joint or I stuck a component in the wrong hole.

EDIT: My drawing and layout appear to be good! My attention to detail during assembly, however, was NOT. There were two problems - I missed a solder joint on both capacitors, and I had a frayed wire that I didn't tin very well bridging two rails. My iron is heating up now, so I'll update if that fixes things!
 
Last edited:
It works! It helps if you solder every joint. 😅 I should have just enough room left on the board to comfortably fit a Fuzz Face with transistor sockets and a bias trimpot, and then I'll stick the whole thing in a 125B. Next step is to remove the yellow output wire, since the LPB-1 will cascade directly into the Fuzz Face.

I've made an LPB-1 into a Fuzz Face using PCBs and it was GREAT, so hopefully this is too.
 

Attachments

  • PXL_20230927_032227542.jpg
    PXL_20230927_032227542.jpg
    278.9 KB · Views: 11
  • PXL_20230927_032235666.jpg
    PXL_20230927_032235666.jpg
    347.5 KB · Views: 11
IT WORKS! I had to get creative to make everything fit, but it was a lot of fun. It's like a puzzle, but I get to make AND solve it! It is too late to mess with transistor choice and biasing it well, so that will happen tomorrow. For now the LPB-1 section is a fixed BC108, Q1 of the FF is another BC108, and Q2 of the FF is a BC109C.

EDIT: I had to change Q2 out or it screeched with the guitar volume knob off. Ended up with a 2N5089
 

Attachments

  • PXL_20230927_065328812.jpg
    PXL_20230927_065328812.jpg
    366 KB · Views: 9
Last edited:
I'd suggest picking up another breadboard so that you can make a circuit work, then use the 2nd breadboard to make it compact (and working) before transferring to the solderable breadboard.

You've started down a slippery-slope... next thing you know, you'll be doing perfboard layouts of your breadboard projects (and perhaps even dallying with vero) which leads to laying out PCBs...


PPCB's own solderable breadboards have the power/gnd rails...

Breadboard.png
 
Breadboard 2.0 is a good idea... I'm going to order another one from Schmalztech and do just that.

I used the Electrocookie boards without rails because of their size. From this point on I'll be using ones with rails.
 
Back
Top