Help with Accuphase A-48 voltage conversion from 100V to 120V

I have a 100V Accuphase A-48 that I am trying to convert internally from 100V to 120V. I did see that there were some posts on this subject, but none of them had the final resolution and the photo of the how the connections looked for 120V. Looking for help from members with experience. Thank you.


This is awesome! Thank you much imhififan.

A couple of follow-up questions:

1. Do I need to measure voltages across any of the connections to ensure that I have made the connections correctly using a DMM?

2. Are there any other measurements that I need to take to double check?

3. Do I need a dim light bulb connection to test when the conversion is complete?

Btw, I assume that this connection configuration has been tested for a 120V.

Thanks again!




Sometimes manufacturers change their specifications or components during production, is your amplifier power transformer has the same color wires connected in the same configuration as the 100V image?

If the answer is yes, you can power up the amp with 100VAC, measure the voltage across RED to BLUE wires and RED to BROWN wires, both should read 120VAC. Since pin #2 and pin #4 are connected to mains voltage and you're using 120VAC mains, so it's safe to swap the wires according to the 120V image.

I always recommend use a dim bulb tester for the first time you power up the amplifier after voltage conversion, if anything goes wrong, the light bulb will simply light up to prevent any damage to the amplifier.

The A-48 idle power consumption is 180watts, so you need a 300watts incandescent light bulb.

I hope that I've answered your question.




I plan to open up the A48 this week. I will let you know if the wires are of the same color. I will test with a DMM to check the voltages and report back. Thanks again!