Imp v2 tone knob

[jimilee]

Gotcha, see if something's touching. I just didn't want you to have to go takings apart if you didn't have to. I just got out my imp. It's a treble cut more than anything. Then I discovered my bridge pickup on my 85 Les Paul isn't working. I'm hoping it's just the switch.


Sent from my iPhone using Tapatalk

[redkurn]

Gotcha, see if something's touching. I just didn't want you to have to go takings apart if you didn't have to. I just got out my imp. It's a treble cut more than anything. Then I discovered my bridge pickup on my 85 Les Paul isn't working. I'm hoping it's just the switch.


Sent from my iPhone using Tapatalk

I've had this thing in and out of the box maybe 20 times, may as well improve the work. XD

I'd think the switch before the pup, I've looked into how long they last and usually depends on quality more than time.

[madbean]

I thinking cleaning up the solder joints with some high concentrate rubbing alcohol (99% Isopropyl) might be in order. Also, you have no hope of fitting that in a 1590A with those 11mm electros. You need to use low profile ones for 1590A builds. I can send some to you if you want

[redkurn]

I thinking cleaning up the solder joints with some high concentrate rubbing alcohol (99% Isopropyl) might be in order. Also, you have no hope of fitting that in a 1590A with those 11mm electros. You need to use low profile ones for 1590A builds. I can send some to you if you want

I printed a spacer for it back when I first made it, you offered to send me some then too.

Rebuilding the pedal now, made a really strong staple header out of thick capacitor leads.

After maybe a hour working it back into the box, the volume pot won't thread anymore, it was a pain to get back in with short leads... so if tone doesn't work I don't care anymore and will just order a new board and parts later if I absolutely need tone from it. XD

I'm done, if it works it works... otherwise it is what it is.

I'd add pics of the internals, it's much better than the first time I wired it and I'm glad to have a better set of helping hands that aren't the flexible kind.
Very tidy and clean, the staple header idea worked out awesome.

Something is touching on the input jack, I'll rebox it later. Tone is still out and I'm too annoyed to bother with it for a while, but I'll just get my printer working again and put it in a slightly larger box.

Trimmed the spacer down so it isn't making contact with the PCB now and the pedal at least works again, but still no tone and not going to worry over it anymore for now at least.

I'll revisit it and try to trace down the issue if I can later when I've turned my 1/4" jack with a capacitor soldered onto it into a pen and it's not as clumsy to use.

[redkurn]

I thinking cleaning up the solder joints with some high concentrate rubbing alcohol (99% Isopropyl) might be in order. Also, you have no hope of fitting that in a 1590A with those 11mm electros. You need to use low profile ones for 1590A builds. I can send some to you if you want

Given how this circuit works I was wondering if jumping the tone pot pins would cause a shift in tone, bypassing the knob altogether?
Got the idea while finally labeling the knobs on the mudbunny.

[redkurn]

Rebuilt my audio probe, I can hear a tone difference when I sweep the pot on the solder joints for the pot, R20, R19, C14 and C10 have very low volume C14 after the capacitor.

I took this cap out and tested it previously and its capacitance is correct, touching the tops of the electrolytic I can hear the signal on some.

Everything from C14 back t IC2 is really low following the trace, I'll draw a line on the board schematic.

Maybe that will help work out what's wrong here.

It may be me imagining things, but I can hear a slight change when using the amp directly...

Also if anyone wants to see the new audio probe I built, it's ugly, not as crap as the original since well everything was free except the clip, the piece I used from jumper wire, super and hot glue and the heat shrink.
Apparently the link expires Jan. 17th, I'll update to dropbox later.
https://share.icloud.com/photos/0242nvqzXO6NR7VK-G-NklPiA

[Zerro]

Just take multimeter with resistance meter (glyph with diode) and reflow all tracks from utmost points to others, to controll if tracks are consistent. By eye you won't see it.

[jimilee]

Can you post pics of the front and back of your build, otherwise, we'll be guessing until the cows come home?


Sent from my iPhone using Tapatalk

[redkurn]

Can you post pics of the front and back of your build, otherwise, we'll be guessing until the cows come home?


Sent from my iPhone using Tapatalk

See page 1, I cleaned it off like Brian suggested.

[jimilee]

Decided today to check the tone knob since it hasn't worked since I boxed it... pot tests good, testing from solder point on main pcb.

What could be the culprit of not getting any play through the pedal for tone?

I would think bad cap, but it was fine until I boxed it and I assumed I broke the pot when I pulled on it a little aggressively.

Edit:
Pulled everything out of the box except the power/audio jacks, tone still isn't working and wiring appears fine, no obvious sign of it having grounded.
Thinking bad cap?
Which cap controls tone, I see a few in the trace diagram, looking at C13 and C14.

Gotcha, sorry about that. Tapatalk isn't showing them.


Sent from my iPhone using Tapatalk

[jimilee]

Decided today to check the tone knob since it hasn't worked since I boxed it... pot tests good, testing from solder point on main pcb.

What could be the culprit of not getting any play through the pedal for tone?

I would think bad cap, but it was fine until I boxed it and I assumed I broke the pot when I pulled on it a little aggressively.

Edit:
Pulled everything out of the box except the power/audio jacks, tone still isn't working and wiring appears fine, no obvious sign of it having grounded.
Thinking bad cap?
Which cap controls tone, I see a few in the trace diagram, looking at C13 and C14.

Gotcha, sorry about that. Tapatalk isn't showing them.


Sent from my iPhone using Tapatalk

Can you use your DMM to test for continuity between r19 and pin 3 of the tone knob, c14 and pin two and r20 and pin 1 also? Then R20 and R22 and r20 and IC2 pin 7. I'm curious about a bad trace.

[redkurn]

Can you use your DMM to test for continuity between r19 and pin 3 of the tone knob, c14 and pin two and r20 and pin 1 also? Then R20 and R22 and r20 and IC2 pin 7. I'm curious about a bad trace.

At pot rolled up = max tone (right)
At pot rolled down = min tone (left)

Continuity between:
R19 and pin 3 of the tone knob - yes neighbor pad to pad, through resistor no
C14 and pin 2 of the tone knob - yes neighbor pad to pad, through capacitor no
R20 and pin 1 of the tone knob - yes neighbor pad to pad, through resistor no
R20 and R22 - yes, after r20 to at start of r22
R20 and IC2 pin 7 - yes, after r20 to pin7
C14 to pin 6 - yes, after c14
At pot rolled up pin 1-3 - no
At pot rolled up pin 2-3 - no
At pot rolled down pin 1-3 - no
At pot rolled down pin 1-2 - yes

At pot rolled up resistance pin 1-3 - 9.5k
At pot rolled up resistance pin 1-2 - 1.076k
At pot rolled up resistance pin 2-3 - 8.68k
At pot rolled down resistance pin 1-3 - 9.5k
At pot rolled down resistance pin 1-2 - 0.6R
At pot rolled down resistance pin 2-3 - 9.5k

Through the pot I get continuity with it rolled all the way down from c14 to pin 1 bus side, when rolled all the way up I do not get continuity to pin 3.

Maybe I need to check the wiring, but it seems the pot internal is bad to me, unless it being 1.076k is normal between pin 1-2 when the tone is maxed.

If the pot is the culprit, can i bypass it some how for approximate middle?
I'm thinking I could by jumping pin 1,2,3 and then I would atleast not have it fully dark as it seems to be doing.

[jimilee]

That's what it sounds like to me too. You can jumper, I think it's pins 1 and 3, that should bypass the pot, but you would need to change the tone cap too. I would replace the tone pot and see where that gets you.


Sent from my iPhone using Tapatalk

[redkurn]

That's what it sounds like to me too. You can jumper, I think it's pins 1 and 3, that should bypass the pot, but you would need to change the tone cap too. I would replace the tone pot and see where that gets you.


Sent from my iPhone using Tapatalk

I don't have one to replace with, not sure what value would be needed, but I do have a limited amount of film caps.
10n, 100n and maybe a few others around that value.

[jimilee]

You can add another 3n9 in parallel and see how you like it, before you go soldering and unsoldering. I'd hate to pull up some pads.


Sent from my iPhone using Tapatalk