NAD - 50w JMP clone

It will look nicer and remove one source of a possible issue. I use a squirter bottle and a small 3/8” wide brush to brush the goop off.
All good advice and much appreciated.
There would be no hesitation if it was something that I had assembled from a bag of parts like my Ceriatone buffered loop kit.

Ceriatone loop.jpg

But if this flux issue is part of the problem, I'm going to leave it as-is until I hear back from Mojotone.
I sent a message through their website with a brief description of current events.
If they want it returned, I don't want to start trying to fix it.

No hurry.
IIRC, there's another amp or two laying around somewhere if I need one...
 
Got a reply email from Mojotone and sent them the pics of the loop installed, along with close up of the discolored 10k resistor.
They had asked about where I was connecting the B+ for the power supply.
Waiting to hear what they say.

Brought the amp upstairs and tried it out on the Alnico cabs.
Definitely something wrong going on with the inputs.
Low input is too quiet, and the MV seems to do very little.
Signal comes through with the MV on zero, and doesn't get much louder as the MV is turned up.
High input goes from off to super loud at 1 on the MV.

It's going back down to the bench and I'm going to disconnect and rewire both inputs and the pre-amp vol pot.
I had visually verified the values on all the associated input resistors and caps, but If I disconnect everything, I can run the individual components through my little magic tester gizmo to check if they are actually what they should be.

Probably wouldn't hurt to do another once over on the rest of the amp while I'm at it.
 
I’m sure you’ll eventually figure it out. The good thing is that you said the voltages you recorded are pretty close to what they’re supposed to be, with the exception of what your measuring at the fx loop.

Good on Mojotone for sending you a replacement… (y)
 
Mojotone sent a $0.00 sales order confirmation, but they haven't shipped the new loop yet.

Took apart the input jacks last night to see if I could track down the odd volume difference.
I separated all the components so I could get good readings on them.

Screenshot 2026-05-15 054449.png

The 3 resistors readings were all in spec, but the 1000pF cap measured about 725, and the 500pF cap read about 260.
Going to be waiting on the replacement loop, so I ordered new caps and a pair of new jacks from Amplified Parts.
 
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