A/B Switch With Led Indicators and Volume Control

Started by MetalMario, September 26, 2014, 05:15:16 PM

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MetalMario

Hi,
i'm building this project http://www.beavisaudio.com/projects/Looper-Switcher/A-B-Switch-Dual-LED.png and i would like to add two potentiometers to regulate the volume for each channel.
Could someone draw me an image on how to do that? I'm doing lots of tries but i don't manage to get the potentiometers work.

GGBB

A picture will take a lot longer than a simple description:

Volume control for output A:
The green wire from the switch connects to pot lug 3 (clockwise).
Pot lug 2 (center/wiper) connects to the tip of the output jack.
Pot lug 1 (counter-clockwise) connects to the sleeve of the output jack (ground).

Do the same with the blue wire for the output B volume control.
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MetalMario

Done that, but potentiometers do not affect the sound as they should.
Sounds stops sometimes when i turn them.
I believe it's an issue regarding the ground wiring.
I firstly built the pedal as the schematic says and it worked well.
Are you sure that i need only what you said? Thank you very much   :)

GGBB

Quote from: MetalMario on September 28, 2014, 09:25:31 AM
Done that, but potentiometers do not affect the sound as they should.
Sounds stops sometimes when i turn them.

Abruptly/gradually?  Randomly/repeatedly?  Temporarily/permanently?  Not a lot to go on, but sounds like it could be either bad pots or bad soldering.

Quote from: MetalMario on September 28, 2014, 09:25:31 AM
I believe it's an issue regarding the ground wiring.

Have you checked your ground connections when "the sound stops?"

Quote from: MetalMario on September 28, 2014, 09:25:31 AM
I firstly built the pedal as the schematic says and it worked well.
Are you sure that i need only what you said? Thank you very much   :)

99.9%.  I'm human - never 100% sure about something I haven't actually done myself.
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vigilante397

#4
I think another important question will be what value of pots you are using and whether they are linear or log. You should also be aware that, since this is a passive circuit, you will not get any boost out of it, you will only have unity gain and below unity. To get better control over your volume you may want to consider putting a simple boost like an LPB1 in front of each output. If you're in anything bigger than a 1590A you'll have plenty of room.
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"Some people love music the way other people love chocolate. Some of us love music the way other people love oxygen."

www.sushiboxfx.com

GGBB

Pot value and taper do matter, and buffering is a good idea (but then an actual circuit needs to be built).  But from the way the problem is described I think the OP needs to sort out the "sound stops sometimes" problem first.
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MetalMario

I believe that i was using bad pots, i'm buying two new ones because i tried with others and worked well.

However, are potentiometers easy to fix? Can they be opened and reassembled easily?
Never done that...is there a tutorial? thanks.

vigilante397

Quote from: MetalMario on October 01, 2014, 06:55:33 PM
I believe that i was using bad pots, i'm buying two new ones because i tried with others and worked well.

However, are potentiometers easy to fix? Can they be opened and reassembled easily?
Never done that...is there a tutorial? thanks.

Definitely not one of the most practical fixes out there, but I have heard of people doing it. In my opinion there isn't much sense in it when pots cost 50 cents a piece (Tayda).
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"Some people love music the way other people love chocolate. Some of us love music the way other people love oxygen."

www.sushiboxfx.com

duck_arse

metal - the first place to look is always the top of the page. it'll usually be at either geofex or amz .....
http://www.geofex.com/Article_Folders/potsecrets/potscret.htm

opened? yes. fixed? sometimes. easy? well, depends.
don't make me draw another line.

GGBB

Quote from: duck_arse on October 02, 2014, 11:34:49 AM
opened? yes. fixed? sometimes. easy? well, depends.

... worth the effort? almost never.  Only recommended for costly or impossible to replace pots, or in an emergency when no replacement is available.  But if you've never looked inside one before - take it apart and have a look.  That's always a good learning experience.
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