Voodoo Lab

This thread was previously in "loop 1 not working", but I started a new one to make things a little bit easier.

I'm still getting a loud hum from loop 1 of my GCX.

When I turn the pedal itself that is in loop 1 off, it's a little better, but if I turn loop 1 off on the GCP, it goes away totally.

All pedals are currently running via battery.

Any ideas?

Well, in the last thread you said that after testing with batteries that the hum went away... so what changed now?

As before, simplify your setup to the simplest form that still exhibits the problem. For instance, start off with your guitar directly to Loop 1 In, connect a pedal to the Send and Return of Loop 1, then run Loop 1 Out directly to your amp.

Without a dead simple test there is no way to figure out where the problem is actually coming from... further without knowing the signal routing you are using while experiencing a problem like this, there is no way to figure out where the problem is actually coming from. Take it one step at a time, and test along the way and you will build rigs that stand up to the pro built racks.

Let us know what you find.

John, you said this on the previous thread:

Connect your guitar directly to the In on GCX Loop 1 and your amp directly from the Out on GCX Loop 1. Maybe add one pedal to GCX Loop 1 and test with the loop on and off.

Let us know what you find.

I did try this, and there is still some hum, but it is much less. Then I put the pedal that is normally in loop 1 (Tight Drive) into the loop and the hum was loud. Then I tried 2 different pedals, and the hum was much quieter, but still there.

Any thoughts?


Thanks!

Perhaps try different cables... If the hum is only when the Loop is active then that would narrow it down to the cables connected to the Send and Return.

Perhaps try a different loop... Is this only on loop 1 or does it only happen when using these specific pedals regardless of the loop used?

Perhaps try moving the GCX within the rack or moving any power supplies away from the GCX and the pedals... What sits directly above the GCX? A device with a large power supply can throw off a large magnetic field that will wreak havoc with the relatively low level, high impedance, guitar signal and any noise introduced here will be greatly amplified when adding gain (of any sort ) to the mix.

I hope that helps!

Thanks John, I have tried different cables, and all of the cables are brand new.

I will try some of these other suggestions though.

My rack consist of a power conditioner, underneath that is a BBE Sonic Maximizer 482I, underneath that is the GCX, Underneath that is a Digitech IPS 33, underneath that is a shelf with my pedals, and underneath all of that is my Mesa Dual Rectifier rack mount head.

Thanks again!

OK, I just ran a noise gate in the post fx loop of the Tight Drive and got rid of the noise. I still have some hum though.

iso transformer's i know in my rack the wireless unit and my amp had to have iso transformers its hard to say without being there is loop 1 the only loop before your amp? if you plug the same cords and fx into #2 does it do it?

I finally figured it out!!!

It's the power supply that was causing the hum. I bought the unit used, so i didn't know it wasn't the proper power supply. I noticed my friends power supply was different, I tried his power supply in my GCX... SILENCE!!!!

Many thanks to my extremely helpful new friend James Brown from Amptweaker for all of his assistance in this matter!

Also thanks to John Clark and anyone else on this forum who had input throughout this mess.

Now, can I order the correct power supply directly from you guys at Voodoo Lab or do I have to go through a dealer?

What was the power supply you were using?

You can order directly from Voodoo Lab by giving us a call or writing to info@voodoolab.com. You can also get a new power supply from any Voodoo Lab dealer.

Good Luck!