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Open Discussion / Re: Is it possible to harness amp foot switch power?

« on: September 06, 2023, 09:31:41 PM »

Fair enough. It sounds like there are 2 main issues. Unwanted noise in the signal path and potential failure of DC blocking to the amp and guitar.

I have some ideas for potential workarounds but I'll have to do some more research.

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Open Discussion / Re: Is it possible to harness amp foot switch power?

« on: September 06, 2023, 07:34:15 PM »

Questioning, debate, and rebuttle are keys to knowledge and understanding, so I'm happy to engage in the back and forth discussion. Thanks

You definitely make some good points that I hadn't thought of. I'm not really looking to build a product to sell. I'm just curious about interesting possibilities. I'll definitely have to do a little more research before attempting anything.

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Open Discussion / Re: Is it possible to harness amp foot switch power?

« on: September 06, 2023, 06:33:43 PM »

Quote from: jwin615 on September 06, 2023, 05:39:09 PM

Quote from: Aentons on September 06, 2023, 01:52:00 PM
Quote from: jwin615 on September 06, 2023, 01:32:37 PM
If this is really an avenue you want to pursue, you could mount a 1 spot in the amp and build a 5 pin cable, din or xlr(or run a separate 2 wire zip tied to your switch cable).
But that all seems overkill...

Also, 50/50 on that DC coming from the amp being very clean. Possibly just some zener diodes between a DC rail and ground.
It's funny you mention using the one spot at the amp because I've already been doing that using a TRS cable. Audio on one line and power on the other. It works great.

My next experiment is going to be running them both on the same line, like true phantom power but, using a combiner box at the amp and break out box on the floor. It will be unbalanced, but as long as there is some power filtering during the break out, I think it should work.

I would advise against that. Issue being that if there is any audio freq noise at all on the power rail, it will end up in your signal path. This is solved in pro audio with the fact that the audio is balanced so any noise is phase canceled.
Also, if your decoupling (DC blocking) ever fails or shorts, you could potentially send DC to your guitar, thus send DC to ground. Also, DC to the input of an amplifier(which *should* have decoupling built in, but still...

I'll defer to Dr. Ian Malcolm:

I hear the warnings and I am hesitant to proceed, but I think this is one of those things I'm going to have to test for myself.

I think a 15 ft shielded guitar cable with an instrument level signal should have relatively minimal noise compared to the longer mic level cable runs that a balanced signal was designed for. A high pass and low pass filter on the audio will hopefully take care of any noise.

We do DC blocking caps on the ins and outs of every pedal, so couldn't any pedal potentially fail and send DC to the guitar? Plus, I'm not convinced DC on a passive pickup is an issue. A pickup is basically a 3k-25k resistor. Please correct me if I'm crazy talkin

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Open Discussion / Re: Is it possible to harness amp foot switch power?

« on: September 06, 2023, 03:10:56 PM »

Quote from: Bio77 on September 06, 2023, 03:00:15 PM

Maybe this is dumb, but would there be enough room for a lithium battery in the foot switch? Could you use the amp's power to charge it? If so, the battery would make up the difference if you needed more current or just go dead if you over do it.

Hmm, good thinking. I'll definitely look into that.

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Open Discussion / Re: Is it possible to harness amp foot switch power?

« on: September 06, 2023, 01:52:00 PM »

Quote from: jwin615 on September 06, 2023, 01:32:37 PM

If this is really an avenue you want to pursue, you could mount a 1 spot in the amp and build a 5 pin cable, din or xlr(or run a separate 2 wire zip tied to your switch cable).
But that all seems overkill...

Also, 50/50 on that DC coming from the amp being very clean. Possibly just some zener diodes between a DC rail and ground.

It's funny you mention using the one spot at the amp because I've already been doing that using a TRS cable. Audio on one line and power on the other. It works great.

My next experiment is going to be running them both on the same line, like true phantom power but, using a combiner box at the amp and break out box on the floor. It will be unbalanced, but as long as there is some power filtering during the break out, I think it should work.

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Open Discussion / Re: Is it possible to harness amp foot switch power?

« on: September 06, 2023, 01:09:28 PM »

Ok, The current is only 8 and 10 mA...bummer. I was hoping to be able to squeeze enough out of a DC to DC converter for 2 or 3 pedals but I guess that's not gonna do it

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Open Discussion / Is it possible to harness amp foot switch power?

« on: September 05, 2023, 09:54:33 PM »

Ok, hear me out.

Some amps have a built-in foot switch that doesn't require a battery or any other external power to light the on-off LEDs. I have a Vox AC30CC and the two switches are for reverb and tremolo. It uses a simple TRS cable. There is DC present on both the tip and the ring. 20V and 13V respectively. It's looks like the hot wires are grounded to turn the effect off.

It's seems like it would be possible use the dc on one of these lines to provide a regulated 9v supply for an auxiliary jack for other effects to use.

Is it possible to split and isolate the DC so that the effect switch still works?

Link to full amp schematic:
https://el34world.com/charts/Schematics/Files/Vox/Vox_ac30cc2_ac30cc2x_2005_sm.pdf

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Open Discussion / Re: Why is so incredibly hard to choose a looper?

« on: September 03, 2023, 05:35:23 PM »

Still waiting... Need a DIY Boomerang. 3 loops, analog dry, and midi clock sync

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General Questions / Re: Toggle switch recommendation for add-on diode clipping options

« on: September 01, 2023, 09:24:45 AM »

The sub mini may work. Can you bend those pins over 90 degrees without breaking?

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General Questions / Re: Toggle switch recommendation for add-on diode clipping options

« on: September 01, 2023, 08:27:08 AM »

Thanks for the quick reply!

It's a premade PCB and it needs to be under the board so I think the only one of those options that might work is the round push/push. I hadn't thought of that one. However, with that option I'd lose the 3rd position that a on-off-on provides.

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