Author Topic: LPB 1 no sound in bypass or through circuit  (Read 226 times)

StompBoxNovice

LPB 1 no sound in bypass or through circuit
« on: June 10, 2021, 01:02:59 PM »
So, my first full pedal project, did some op-amps years ago as well as some breadboard pedals using programmable chips.

I decided on an LPB-1 as it seemed easy and would fit in my enclosure (old tobacco tin) for some reason, even the bypass doesn't let signal through. There is a hum in bypass, but no audio.

Any help would be much appreciated, using a multimeter, there is a signal path in bypass but not through the PCB.










Marcos - Munky

Re: LPB 1 no sound in bypass or through circuit
« Reply #1 on: June 10, 2021, 02:02:07 PM »
First of all, welcome!

We need more photos of your build, showing the board both sides and jacks wiring. Also are you sure nothing is touching the metal enclosure and causing a short?

StompBoxNovice

Re: LPB 1 no sound in bypass or through circuit
« Reply #2 on: June 10, 2021, 06:21:50 PM »
My thanks!

Been lurking for a bit whilst I was waiting for parts, was hoping for a "Look at my first build, isn't it great" post, but unfortunately not!

The casing has been lacquered, so is no longer conductive.

Both Jack's have been wired the same, with the black cable being earth.

Many thanks!








Sorry, hard to get good photos with the cabling in the way, but it's the same as the design further up
« Last Edit: June 10, 2021, 06:23:32 PM by StompBoxNovice »

antonis

Re: LPB 1 no sound in bypass or through circuit
« Reply #3 on: June 10, 2021, 06:52:32 PM »
The casing has been lacquered, so is no longer conductive.

Good for board isolation but bad for external interference.. :icon_wink:
Could you plz post a 3PDT switch wiring schematic..??
BTW, Volume pot is wired backwards..
(lug 1 should go to GND..)

P.S.
Welcome, also.. :icon_biggrin:
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

StompBoxNovice

Re: LPB 1 no sound in bypass or through circuit
« Reply #4 on: June 11, 2021, 06:14:43 AM »
Could you plz post a 3PDT switch wiring schematic..??
BTW, Volume pot is wired backwards..
(lug 1 should go to GND..)

P.S.
Welcome, also.. :icon_biggrin:

Many thanks for the welcome and the heads up about the volume pot, I'll switch it around in a second.

In regards to the 3PDT, left to right is output, input LED with position 1 being bypass and position 2 being PCB

duck_arse

Re: LPB 1 no sound in bypass or through circuit
« Reply #5 on: June 11, 2021, 11:10:25 AM »

Both Jack's have been wired the same, with the black cable being earth.



Sorry, hard to get good photos with the cabling in the way, but it's the same as the design further up

also welcome, and no green face from me.

it is my opinion only, but I think your statement about wired the same is incorrect. the above photo suggests to me that you have wired that jack to the normally closed contacts [that is, when you shove in a plug, the contact opens] instead of the common contacts [that is, the contacts that swing in the switch, common to both open and closed states].

because one jack faces up and the other faces down, but the wires are on top on both.
Now battery powered. Remove plug when not in use, please.

StompBoxNovice

Re: LPB 1 no sound in bypass or through circuit
« Reply #6 on: June 11, 2021, 11:27:31 AM »
The jack's have a constant connection, they only move to entertain space for the male Jack. Either side can be soldered and it will connect (I'm guessing these inputs were designed for breadboards more than anything else, giving you the ability to attach on either side of the break)

duck_arse

Re: LPB 1 no sound in bypass or through circuit
« Reply #7 on: June 11, 2021, 11:51:07 AM »
well, now you've got me, I don't understand. can you take a photo of the jack with a plug inserted, showing the fingers, please? I might need to do a red face instead.
Now battery powered. Remove plug when not in use, please.

FiveseveN

Re: LPB 1 no sound in bypass or through circuit
« Reply #8 on: June 11, 2021, 12:25:29 PM »
Either side can be soldered and it will connect
Nope. Plug a jack in and check again, duck_arse is correct.
Does the circuit sound better when oriented to magnetic north under a pyramid?

StompBoxNovice

Re: LPB 1 no sound in bypass or through circuit
« Reply #9 on: June 11, 2021, 02:24:39 PM »
DuckArse was correct, my apologies!

The bypass is working! The PCB was working until I tried putting it into the enclosure, I'll have to go over it again tomorrow, see what's happening! Thanks for the help!

GibsonGM

  • more
  • Awesome!
  • *****
  • Posts: 5780
  • Total likes: 908
  • Mike Parker (aka. Guitar Mike, Parks, etc)
Re: LPB 1 no sound in bypass or through circuit
« Reply #10 on: June 11, 2021, 03:11:21 PM »
DuckArse was correct, my apologies!

The bypass is working! The PCB was working until I tried putting it into the enclosure, I'll have to go over it again tomorrow, see what's happening! Thanks for the help!

With a metal enclosure like that, you must put thick cardboard, non-conductive foam, tape, or something else inside to make sure the bottom of the PCB will not touch the metal. If it does, it can short out, making the effect go silent or WORSE, it could cause components  to short and fry!!   Make SURE nothing can touch the metal bottom, walls, or top of the can...I hope it works when you take it out, then you can insulate the box...

I use a packing foam, cut to fit, that is definitely non-conductive (some of it can be), it is similar to pipe insulating wrap or the foam they use on bikes to you don't fall on the bar badly...  ;) 
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

duck_arse

Re: LPB 1 no sound in bypass or through circuit
« Reply #11 on: June 12, 2021, 10:07:40 AM »
Quote
.... you don't fall on the bar badly...

this happened to me once.

the easy way around the switching aspect of those plastic jacks, I find, is to simply link across each set of pins. I doubt there are many here who haven't been caught using the wrong pins on a plastic jack at least once.
Now battery powered. Remove plug when not in use, please.

WoundUp

Re: LPB 1 no sound in bypass or through circuit
« Reply #12 on: June 13, 2021, 12:02:03 AM »
I actually just got done breadboarding this exact circuit and was having my own problems. It was dead silent. First, I had to redo the circuit because I mucked it up somehow. Then I tried again and same thing. It took me about 15 minutes of head scratching to realize I forgot to put power to part of the circuit that runs to the collector of the transistor lol.

I had already given up for the night and everything. Then it hit me that I forgot to power the dang thing  :icon_lol: It works great now. I'll probably try it on perfboard next. I don't have an enclosure to use for it so I'll have to wait and build it out once I get one.