Author Topic: chinese true bypass wiring  (Read 511 times)

moody

chinese true bypass wiring
« on: January 11, 2018, 06:02:13 AM »
Hi all.  I registered here to ask about something that is probably off topic but I have used this forum before when I was building some pedals a few years ago.  My knowledge of this stuff has faded somewhat since I had kids.

I have recently bought a cheap octave pedal on ebay from china - mass-produced stuff and not worth the effort of trying to get a refund / replacement.  It seems pretty well made and sounds good, however, it has a very loud pop when switched in or out and due to the tiny size of the pcb, hidden double sided boards and smd components, I can't begin to figure out even the easy input / output section of the circuit.

Is there anything I can do easily (the dreaded pulldown resistor) that can be seen from the photos I am attaching.  If not, I'm going to get a looper pedal and just leave this thing on all the time.  I have the basics, soldering iron, resistors, capacitors and a decent ability to follow instructions.

Thank you!




italianguy63

Re: chinese true bypass wiring
« Reply #1 on: January 11, 2018, 06:44:15 AM »
Sorry-- But I love it is Stompbox model #000.01

MC
The reports of my death have been greatly exaggerated -- Mark Twain

antonis

Re: chinese true bypass wiring
« Reply #2 on: January 11, 2018, 06:48:05 AM »
Try to solder a 1 - 2.2 M resistor between IN jack lugs (Signal - GND)
(not officially recomended, but... 8))

Maybe you'll have to do the same on OUT jack, if it isn't already grounded (e.g. via Volume pot, which doesn't exist in your pedal..)

Take care or soldering iron temeprature/soldering time 'cause it's easy to melt jack's plastic body..  :icon_wink:

P.S.1
Next step is to wire 3PDT switch PCB for IN/OUT grounded when effect by-passed..

P.S.2
WELLCOME..!! :icon_biggrin:
« Last Edit: January 11, 2018, 06:51:34 AM by antonis »
Can't follow your signature changes, Stephen..!!

moody

Re: chinese true bypass wiring
« Reply #3 on: January 11, 2018, 07:14:08 AM »
Try to solder a 1 - 2.2 M resistor between IN jack lugs (Signal - GND)
(not officially recomended, but... 8))

Maybe you'll have to do the same on OUT jack, if it isn't already grounded (e.g. via Volume pot, which doesn't exist in your pedal..)

Take care or soldering iron temeprature/soldering time 'cause it's easy to melt jack's plastic body..  :icon_wink:

P.S.1
Next step is to wire 3PDT switch PCB for IN/OUT grounded when effect by-passed..

P.S.2
WELLCOME..!! :icon_biggrin:

Thank you!

This is not point to point wired by any means, I have soldered up valve amps and some vero board pedals but this is a different story :D

There is an led daughter board soldered in over the top of where the jacks wire in to the main board.  The tip of the jack for the input side appears to, but I am not certain, go direct to the central mounted 'upper octave' volume control.  I can see the lug for the sleeve labelled R60.   I can't get to any of the lugs for the output jack (completely covered).

I will not be able to remove or get to the tip lugs without removing the daughter board - I don't think that would end well.  I can't remove the upper octave volume control without removing the jack body and vice versa.

I am thinking that the best option from what I can see would be to drill a tiny hole for the resistor wire in the contact tab of the jack - at a point with as little as possible physical movement.  Opinions?

Meanwhile the positive wire for the power connector has come off.  easy fix but 'just' what I didn't need.

antonis

Re: chinese true bypass wiring
« Reply #4 on: January 11, 2018, 08:19:49 AM »
On a second thought, you can easily find 3PDT switch PCB IN/OUT/GND with a multimeter and solder there pull-down resistor(s)..

(I wish popping doesn't occur due to LED activation, 'cause you'll have to find space for an 10μF electrolytic capacitor..)
Can't follow your signature changes, Stephen..!!

EBK

Re: chinese true bypass wiring
« Reply #5 on: January 11, 2018, 08:20:44 AM »
I am thinking that the best option from what I can see would be to drill a tiny hole for the resistor wire in the contact tab of the jack - at a point with as little as possible physical movement.  Opinions?
Please don't drill any holes.  My suggestion (which antonis just beat me to by a few seconds  :icon_lol:):
You have access to the terminals of the jacks via the stomp switch.  Dig out a multimeter and figure out which pins go where, and when you find the FX IN pin, add your resistor there.

See above.   :icon_wink:
« Last Edit: January 11, 2018, 08:24:46 AM by EBK »
No affiliations. If I glowingly mention specific merchants or products, it is because I like them without having to be paid to like them.

Fender3D

Re: chinese true bypass wiring
« Reply #6 on: January 11, 2018, 12:48:09 PM »
Sorry-- But I love it is Stompbox model #000.01

MC

lol
it even goes 10 ctaves and 20 ctaves down
"NOT FLAMMABLE" is not a challenge

EBK

Re: chinese true bypass wiring
« Reply #7 on: January 11, 2018, 01:14:05 PM »
Sorry-- But I love it is Stompbox model #000.01

MC

lol
it even goes 10 ctaves and 20 ctaves down

My brain wants to read it as 10 cents and 20 cents, tiny fractions of a semitone.   :icon_razz:

If they had used 8vb and 15mb for those labels they would have fit just fine. 
No affiliations. If I glowingly mention specific merchants or products, it is because I like them without having to be paid to like them.