Hi Zensview, 

I have the same amp and I am thinking of converting the voltage for it. 

Have you converted your Accuphase amp? Does the conversion change the sound quality?

Thank you. 

Hi there 
Yeah, it works well, and so far So good, I haven’t notice anything wrong during listening.

Thank you for your input!

@imhififan

I have converted the voltage to 120v. All is good except for one thing.

I used the 3-prong US power cord (the one with ground prong) to test.

When the amp is on and no music is played. If I stand close to the speakers, I can hear the white sound from the speakers.

I suspected this has something to do with ground prong so I removed it and tried again. The white noise disappeared completely. I played some test tracks for 3 hours and found the sound is exactly the same as when the amp was on Japan voltage.

I wonder if there is any way to fix the white noise issue with the ground prong?

Thank you.

Please note that, I filled the K3 and K4 holes with lead to strengthen the board. 

@quanghuy147 

If you disconnect ALL sources from the E600, connect ONLY the speakers to the E600 and use a 3-prong power cord to power up the E600, can you hear any noise if you turn up the volume?

@imhififan I just came home from work and test. When I disconnect all sources from E600, only the speakers are connected to the E600, 3-pong power cord is used, I don't hear any noise even when I turn up the volume to 12 o'clock position. 

When I disconnect all sources from E600, only the speakers are connected to the E600, 3-pong power cord is used, I don't hear any noise even when I turn up the volume to 12 o'clock position.

I believe the noise problem is not the E600, please connect the sources one at a time to test and see which one causing problem.

@imhififan I disconnected all sources and connected each one at a time, I found that the DAC produced noise the most. Other sources did have some noise but much less. 

What concerns me is with another amp, the noise level from the DAC is just about 50% compared to with E600. 

Currently, I am using the Accuphase APL-1 power cord, which doesn't use the ground prong. The E600 is dead quiet. The AP-1 power cord is a great power cord, it's a big jump from generic power cable.

However, it would be great if I could use other 3-prong hi-end power cords with E600.

@quanghuy147 

It seems like some grounding problem between components. Would you provide detail information what components are in your system and how they connected together, maybe we can figure out what is the culprit.

@imhififan I have borrowed 1 DAC and 1 pair of speakers from dad to test this Accuphase amp. 

Here is what I found: 

-the pair of speakers that I borrowed has lower sensitivity so the noise is lower

-the DAC that I borrowed has lower noise than my DAC 

-if I use 2-prong power cable (the one with no ground cable) for the DAC, there is absolutely no noise from the speakers. 

My system are like this: 

-Computer (small form factor, no monitor connected) -->USB--> DAC --> Amp --> Speakers

-Computer, DAC are connected to their own power conditioner

-Amp is connected to its own power conditioner. 

I think you have the similar problem.

https://forum.audiogon.com/discussions/usb-input-causes-noise-across-whole-amplifier-musical-fidelity-m5si

@imhififan Thank you very much! The link is very helpful. At least now I know the cause of the issue. 

@imhififan Just wondering if Accuphase E470 voltage conversion from 100v to 120v is same as E600? I'm thinking to give class AB a try as well.

I think E470 has different layout, if you can post a picture of the voltage selection board, maybe I can provide some help on the voltage conversion.

@imhififan Thanks following up, good to know the E470 does different in the voltage selection board, How about E480, is it pretty close to what E600 voltage selection board?

Would anyone have information on the conversion of an Accuphase E370 from100v to 120v?     Thank you. 

https://photos.google.com/search/_tra_/photo/AF1QipOxSUAYxSQAQeNdKQexCuHuQj0wJSanEsOBaXKK

https://photos.google.com/search/_tra_/photo/AF1QipMbSq71oxnih3G9-UY9XoOAb6IxGI-_bR3E4shg

https://photos.google.com/search/_tra_/photo/AF1QipPUVQ1ajlUPAPc_DtI--uX1FMp2lMjEYqZDqVex

@pip555

Can you post the photos directly? Without google account I can’t access to it.

People need to be aware that Accuphase only offers parts support and service for their products supplied through their local distributor.They make no exceptions.

@jtgofish : haven't seen any broken Accuphase unit yet even 30+ yr still running cool! 

Hello imhififan,

I am not the most computer saavy, but I saved the photos to 'my system' on Audiogon.    

Like many of the other conversions, the position of a few jumpers have to be changed.  Please let me know if you require any more photos.  Thank you very much.  

@pip555 

Can you post a picture the back of this PCB?

Not sure if I can help, perhaps from the picture we can figure it out. BTW, are you comfortable of using a DMM on mains voltage? 

I have posted a photo of the back of the PCB on 'my system' page.

I also took a photo of the wires and their orientation from the transformer.  The three wires from one side of the transformer feed to the white plug.  The four wires from the other side of the transformer feed the blue plug.  

I am confortable using DMM on the mains voltage.

Thanks

@pip555

Thanks for posting those images, for 120V mains, I believe J1 should moves to J4, J3 moves to J5. And J2 remains in the same place.

Before you move the jumper wires, please measure the following resistance and post the result to make sure if the projected configuration is correct:

Black - Brown

Black - Red

Orange - Yellow

Orange - Blue

Measurement should taken from the plugs out of the sockets.

imhififan,

Thanks for the information.  Hopefully I will have some time this weekend to test out the board.  I will post as soon as I do.  

Cheers

imhififan,

I received the following readings (all in ohms)

Black - Brown 1.3

Black - Red 1.6

Orange - Yellow 1.4

Orange - Blue 1.6

I hope that this information will help. 

Thanks

@pip555

Thanks for the measurements, the readings confirm that brown and yellow are 100V windings, red and blue are 120V windings.

You can go ahead to move the jumper wire J1 to J4, J3 to J5. That will change the voltage setting from 100V to 120V.

imhififan,

Thank you very much for your assistance.  I will try to make the changes in the next day or two.  I will give you an update then. 

Cheers

imhififan,

The changes were made, and everything is working perfectly.  The drawing of the transformer taps was extremely helpful.  Thank you very much for your assistance.  

Cheers

🥂

I'm glad to be of help🙂