AC hum with single supply and splitter

[Martin mayhead]

I just got my Fosi Audio v3 mono block package - 2 amps with a single 10A supply, DC filter and splitter cable. I have to say I am quite disappointed because there is a mains hum (50Hz in the uk) that is clearly audible. And if one amp goes into idle before the other then there is a buzz. Obviously there are some nasty interactions through the common supply which a single DC filter doesn't address. I don't think Fosi Audio should be selling this package as it is because it is clearly sub-standard.
I'd like to know from he manufacturer how they're going to fix this issue for me and others that may be experiencing it.

 

[wookie1411]

I have today the same problem. 1 month pleasure and a terrible hum sound

This is very bad and I am not happy about it!

I think the package 2x V3 is not totally tested before release.and when I turn my Amplifier of and after 10 min the v3 turn off. En in the evening (the Amplifier is off, one of them are turn on) this a big bug in the power unit.

 

[Martin mayhead]

@customer support - are y9ou going to respond to this or my emails please? I am very disappointed with your (lack of) response so far.

 

[wookie1411]

I have returned the fosiaudio v3 package back to Amazon. I was not happy with a new product and did not work properly.

 

[Martin mayhead]

I've replaced the 10A single supply, filter and splitter that came in the package with 2 Aiyima GAAN 48V 10A supplies, 1 for each v3, and it all works really nicely now. No hum, no triggering each other on/off and no turn on/off pop. I kept the amps and I'm trying to sell the Fosi supply. I am fairly sure that a pair of the Fosi supplies would work just as well as the Aiyama's but you can't buy them outside of a package in the UK. In truth a pair of 48V 5A supplies should also suffice.
I'm disappointed that Fosi haven't responded to this or to the negative feedback I have had to post on eBay as the result of their dire (non-existent) customer support.

 

[Miha123]

So what up with this.

I feel scammed.

 

[Miha123]

I am writing to support and they are full of excuses. Like it is RCA cable fault, which is not.

I think the package 2x V3 is not totally tested before release.and when I turn my Amplifier of and after 10 min the v3 turn off. En in the evening (the Amplifier is off, one of them are turn on) this a big bug in the power unit.

Thi also happens to me. When I test them when just turned on evetyhing works, when they on for some time, strange things happen. and I have everything properly grounded and stuff-

 

[Massimo]

I had a similar problem. I thought it was the amplifiers but in the end it was the cable I used to connect the computer to the rca input. After replacing the cable with a higher quality one, the hum disappeared and the quality improved. I don't know if it's the same problem but I recommend trying with different cables

 

[Miha123]

But I have it connected to via usb, so it is a digital connection. I do not think replacing an usb cable will help thou.