DIY AA764 Champ Squeals Loudly

[Jazz P Bass]

The Vibrato doesn't work correctly.
And the amp hums.
Hums when.
Without any input it should be relatively silent.
With input, volume on zero, the same.
Max the controls with a single coil pickup, it will hum.
I have attached Fenders schematic & layout.
Compare them to your amp.
Look for something different on your build.
(ie: maybe incorrect)
If the amp that you have follows the original Fender design, trust the original.

[jighead81]

The Hum:
It hums with or without input. Could this be from not grounding the shielded input wire from the 68K's to pin 2 of V1 and from pin 7 of V1 to Middle lug of volume pot? That's the next step tomorrow is to ground those if anybody thinks it's necessary. I figured the shield isn't doing it's job if it's not grounded on one end.

The Vibrato:
Also, the vibrato still isn't working. I think I might have something mis-wired under the board. I should've routed what I could up on top since this was my first build, oh well.

I think the pdf up there from jpb is for a vibrolux reissue?
Here's the one I'm working off of: http://www.thevintagesound.com/ffg/s...764_layout.gif

Thanks again!

[jighead81]

Update

I fixed the hum issue finally. I realized the Cap can I received from triode electronics was a 40 20 20 20 and the 40 uf wasn't being used, so I ran it parallel to the turret that connects the 1K 2W resistor and the OT center tap. Now there's zero hum, and I learned a whole heck of alot. This was fun.

Also the vibrato started working after I changed out the caps, but I don't think I'll ever use vibrato anyway, so I'm putting in a reverb circuit. Google champ reverb, it looks pretty cool.

Thanks for all your help jpb