PX8 Plus Volume Drop Issue

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
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Joined: Thu Mar 08, 2018 2:33 pm

PX8 Plus Volume Drop Issue

Post by daveymcmillan » Thu Mar 08, 2018 2:39 pm

Hello! First post here!

I'm having an issue that I can't quite figure out. Just finished setting up my board and effects loops. All of my pedals seem to function and sound perfectly fine within the specified loops. However, the two TC Electronic pedals (Flashback and Hall of Fame 2) seem to have volume drop issues. I've tried different loops, different patch cables, and different power cables. The issue remains. It's almost like the two pedals cannot be isolated in a single loop, but need to be in-line w/ the guitar versus separate. There just isn't even throughput to keep the volume from dropping nearly 75% and sucking the tone. Unfortunately, the two TC pedals don't have a volume to increase the output either. However, if I just take out the PX8 and put the pedals into the loop just through the amp, works fine!

Any guidance or suggestions would really help me out.


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Location: The Lab

Re: PX8 Plus Volume Drop Issue

Post by JohnClark » Fri Mar 09, 2018 11:46 am

The Loops themselves shouldn't be able to do this unless there are failing cables being used to connect the pedals. However there is a buffer on the Output of the PX-8 so maybe it is somehow causing the trouble?

You can test this by running these pedals in any of Loops 1-6 and using the Insert Send as the output to see if the offending pedals still have a big level drop.

If the problem goes away, then you can open up the PX-8 and bypass the buffer circuit. This requires the following...
1. Removing the eight #2 Phillips chassis screws (four on the top, four on the bottom).
2. Removing the top half of the chassis.
3. Next to the Output jack are a pair of jumpers that you will need to move from the "Quiet Switching" position to the "Bypass" position.
4. Replace the top half of the chassis.
5. Replace the eight chassis screws.

Alternatively, if it is caused by the buffer you can send us your PX-8 so we can repair it.

I hope that helps!

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