Pop on Mesa channel change

[rpbale]

I am using the GCX and the ground control to change channels on my Mesa stiletto head. Going into channel 1 I'm fine,but going into 2 it pops pretty loudly. It does not do this with the stock mesa foot switch.

I have had one ocassion to rearrange my set up and moved to a different loop and the problem followed to the next loop. I am using every loop on the GCX withou any other problem. My Marshall switches channels without a pop.

Any suggestions?

[rpbale]

In continuing to read up on related popping issues I read that adding resistor across the leads would neutralize any DC offset to stop a pop. I would think it's better to do that on the outside of the gcx so as not to have to disassemble the gcx. Can anyone recommend an ohm rating?

Does any of this sound like a good approach? Where I read this was with respect to the guitar signal not necessrily the channel change signal. I understand Mesa uses cross fading to change channels rather than just a relay.

[rpbale]

I'll open up the mesa footswitch to verify the circuit. I believe Mesa's TRS cable arrangement is only needed if one is changing the solo and channel on the same cable. Maybe the solo circuit is bleeding into the channel change circuit since I'm just using the 2-conductor cable??

Based on the LED being present in the mesa footswitch their must be DC on the line and the LED is taking some of the load. I assume the GCX doesn't have an equivelent load inside it.

Maybe I can make a lttle inline box with two jacks with a LED or equvelent resistor so that the Stiletto can't tell the difference between the GCX or the original footswitch.

How would one go about determining the resitance of an LED because if understand it correctly resitance goes does over a certain amount voltage?

Thanks, Rick

[JohnClark]

I believe the resistor mod you are referring to was a fix I offered for a very specific pedal and is not at all the fix for this case. Do not do this!

Likely the solution here will be to use a speaker cable or other side by side, or twisted pair cable rather than an instrument cable.

[rpbale]

I will check the cable ASAP and let you know the results

[rpbale]

I finally got a chance to try the channel switching with a speaker cable between the amp and GCX instead of with the instrument cable. No change. It still pops as before. The pop seems to be gain related. I typically run the gain much higher on the 2nd channel. But if I up the gain on channel 1 then I can get the same pop there also.

Any ideas? Again no popping occurs when changing other GCX loops. The mesa doesn't using it's original footswitch.

[JohnClark]

Is there anything else connected to this GCX loop? You should only have a single cable that connects between the GCX loop Out jack and the Channel EXT Switch jack on the amplifier.

[rpbale]

Nothing else is on the loop.

[JohnClark]

How long is the cable you are using for this? Perhaps test with something really short if you can. Does the Mesa footswitch connect to the same EXT Switch jacks or is there a separate footswitch connection under the main amp chassis? If it connects to a different jack, what is it... 1/4" TRS jack or a multi-pin DIN jack?

[rpbale]

That was a good question. The Mesa foot switch uses a single front panel TRS to control channel and solo on one line.
The GCX is hooked up to use the separated jacks on the rear panel.
Cables are short.