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: http://www.tonepublications.com/review/musical-fidelity-v90-amp-and-v90-dac/

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!
Matthew
bomd
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.

Best,

Erik
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.

Cheers,
Matthew


If it's a hum or buzz, it could be DC on the line. You would need something like this to filter the DC http://emotiva.com/products/accessories/cmx-2

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.
Hi Matthew,

I have the same issue with my new v90 amp that I received from Music Direct yesterday.  The unit is a new one, and I noticed it immediately after I turned it on.  Did you hear back from Musical Fidelity?  Also the volume doesn't go down to zero, so I can't turn it down to a very quiet volume level.  Is your unit like that also?  

Regards,

Jay
Hi Jay,

Never received a response from Musical Fidelity's USA rep.  I did reach out to Music Direct and they were very responsive at first.  Even though I was out of my return window they attempted to contact Musical Fidelity on their end.  However, I never received a response from MD and MF after that initial point of communication.

I also had the same problem with the volume not going to zero.  Sonically I thought the V90-Amp was really nice for the price.  I was happy with the DAC, and it drove my vintage Polk Monitor 4s very well.  In the end I was getting sick of hearing it make noises on my computer desk and recently traded in the V90-Amp to a local HiFi shop for a NAD D 3020. 
Hi Matthew,

I'll contact Music Direct and Musical Fidelity and see what they have to say. That's too bad you didn't receive a response from either company. If both issues are normal, I'll likely keep it as it does sound quite good, especially for the asking price of $149 for brand new units, as they are now discontinued and on clearance.  I hope your NAD D 3020 sounds terrific and even better than the V90 Amp it replaced.

Cheers!