Musical Fidelity V90-AMP Noise Issue

Hi Folks,

First post on the forums. Sorry if this is not the correct topic area to put this thread.

I have a Musical Fidelity V90-AMP that I use for my computer audio setup. If you are not familiar with the component there is a good write up over at Tone Audio:

Sonically I am very happy with the unit. I have an Audioquest USB cable and Jitterbug going from my iMac to the V90-AMP, and this little guy is powering a pair of vintage Polk Monitor 4s mounted on speaker stands.

The only drawback is that the V90-AMP has a high pitch hissing sound that comes directly from the body of the unit. I put it on isolation feet, and it helped reduce the noise a little, but it is still noticeable while sitting at my desk. When I am blasting music it is a non-issue, but sometimes when listening to quieter classical, or more ballad-oriented jazz music it can be distracting.

I also noticed that if I put pressure or weight on top of the unit it does reduce noise significantly. I was thinking of getting a small 2.5 to 3 pound weight to put on it, but then I thought long term stress of the weight may possible damage the inner workings of the V90-AMP.

Would love to hear anyone’s thoughts regarding this issues. I have only gotten into this hobby a little over a year ago and am still learning a ton.

Thanks, and cheers!
IF it's hissing, turn it off. Sounds like a cap blew.

If it's just buzzing or humming, it could be a bad cap, bad diodes or bad transformer.

Either way, off to the shop it should go.


Hi Erik,

Thanks for the reply. 

I purchased it from Music Direct back in March.  It was a demo discounted item, but I believe it still came with the standard Musical Fidelity warranty.  

The sound has been happening since I have received it back in April.  I guess I was wrong to describe it as a hiss.  More of a jittering buzz is would be accurate. 

Sounds like it is worth sending message to MF to see if they have any solutions.


If it's a hum or buzz, it could be DC on the line. You would need something like this to filter the DC

Has this been the case since the unit was new or did it just start happening? Have you changed anything electrically (i.e. new appliances, new outlets, move equipment, etc.)?

FWIW I have a Musical Fidelity M6si and there is no internal noise of any kind emanating from it.
It has been happening since I received the unit.  I shot an email to Musical Fidelity last night.  Hopefully they will respond with some input.

I'll mess with trying different power receptacles this weekend.  There hasn't been any substantial changes added to our house electrical wise..

Understood. Assuming you're in the U.S., other than Randy Bingham there is no email contact. Please let me know if you have an address for the UK. You may want to talk to the place you purchased the unit from.

Back to electrical, if it is a DC issue you cannot resolve that simply by trying different power receptacles.  You would need a DC filter.