Accuphase E-480

@foolishman,
Congratulations! Please let us know the jumper settings for 120V, maybe a close up picture will be nice, it will help other members if they need to do voltage conversion. Thank you in advance!

I don't have any experience on E480 voltage conversion, however, based on previous experience, brown & red wires are 100v windings, and orange & yellow are 120v windings. You need to trace the circuit to connect jumpers for orange & yellow wires and disconnect jumpers for brown & red wires.
From the picture, seem like j1, j2 & j3 are jumper for soft-start resistors circuity. Connect j2 and disconnect j1, j3 for 240v main. No change required for 100v and 120v main.

Congrats! @sp33ls2

One thing I was a little bit surprised by was that some of the rails to the power amp board were raised by a few volts (like 65VDC to 69VDC) when compared with the 100V step down... My AC mains are 122VAC rather than 120, while the stepdown is at exactly 100V -- maybe that's part of explanation of the increase of a few volts?

Yes, that's the reason and nothing to worry about.

I see one trim pot on each amp board, but not sure if that's for DC offset or bias. Do these units have a self-biasing circuit, I wonder?

Most new design Accuphase power amp has no dc offset adj pot. I believe the trim pot is for bias adjustment and the +/- test point should has a reading of 4mV, but I not 100% sure since I don't have a service manual on hand, perhaps you can measure it to confirm.

I believe the trim pot is for bias adjustment and the +/- test point should has a reading of 4mV...

Correction:

I believe the trim pot is for bias adjustment and the +/- test point should has a reading of mV, perhaps you should measure and recorded it for future reference.

just wanna confirm that change its 100v for 120v, I only need change below jumper setting 

J4 -> J5

J10 -> J8

J6 -> J11

From previous experience of Accuphase amplifier voltage conversion, change 100V to 120V only required move two jumpers!

I hope some one can posts images of E480 power board (front and back) so I can verify the correct jumper settings.