Zoom g1xon and diy guitar amp based on lm386

[Oooscar]

Hello all,

Recently I bought a Zoom G1xon effects processor, and I am trying it with a homemade amp I did based on an LM386 ic. I didn't expect to work properly. What happens is that any guitar I connect to the g1xon and to the amp produced in general a lot of noise, and if I turn the volume of the guitar up, a high pitch squeal, like feedback sound starts to sound. Have you had these sort of sounds in any unwanted situation? Maybe I can get some tips to solve it. The amp by itself with just a guitar works well, with a bit of hum of course, but fine. I attach a photograph of the diy amp.

[tonyharker]

You appear to have some parts missing from your amplifier board. Including the input level pot. The g1xon is probably putting out too much volume for your amplifier so you will need someway of turning it down. What gain did you set for the LM386?

[Oooscar]

The idea for this small amp was to make it as simple as possible, and to get the maximum of it. So I decided to control the volume with the guitar volume control, and the gain of the LM386 is set to maximum. Pins 1 and 8 are connected together with a wire, like in a smokey amp. Some of the patches give me more trouble than others, but in general, as soon as I crank up the volume control of the guitar, the squeal comes in. I would like to get still a nice volume to fill the room, 

[Jazz P Bass]

You will have to install something to limit the gain.
Some of the Zoom patches are off the wall high gain.
I have often wondered why they chose to do this.
You go from one one patch to the next one in line and the gain is off the charts.

[Oooscar]

I have tried with a different lm386 amp that I have with volume control, and at some point starts to happen. I also have tried disconnecting the pins 1 and 8 of the amp of the photograph, and the problem still remains at some point. I noticed that when I touched the strings with my hand the squeal disappears, but when I touch the strings with some fabric, textile, for instance, the squeal does not vanish.

The other road to go is buying some device. I would prefer not to do it, or buying something economical.

[Jazz P Bass]

Pin 1 & 8 of the LM386 set the gain.
You are supposed to use an e cap (10uf) for more gain.
Not a jumper wire.
No cap and the gain is set to 20.

[Oooscar]

Yes... Well, I learned today that the g1xon has different level controls, one of them, the master level can make a difference. I will keep trying. Maybe I can use my nice diy amp after all...

[Oooscar]

Just to share with you...

I have tried the g1xOn with a generic TDA7297 stereo amp board bought on eBay, and I can get louder volumes without the squeal... (I am bit experimental... But it seems you can get nice volume and sound in a cheap DIY way) I have been told as well that cheap pickup coils can also contribute to produce that squeal, due to microphonic effects. Wax potted ones have less microphonic effect. In the future I will try better pickups also.

[Lex]

I have the same Zoom and I play it through several amps without a problem.
The thing is to find within Zoom deep menu the right setting that works for you.
This is imo the only 'less' thing about this wonderful device ... going deep in the menu.
However, "ToneLib Zoom" editor gives you an opportunity to connect Zoom to an external device (with a bigger screen) for easy access to the menu.
Cheers