2. amps-preamps
  3. 1256962970

1st setup failed, need advice for B&W N805 amp

Okay, so my current components are failing me. I have a Peachtree Decco and Emotiva UPA-2 (just received this, motive for my post).

I was previously using only the Decco to power the N805's... my source was my PC connected via USB. So the Decco functioned as a DAC/preamp/amp and all was fine... except two things. 1st, although the room is small, I could use a bit more power. 2nd, I noticed the left channel on the Decco was a bit louder than the right. At first I thought it was the speakers, but I tried another set and same thing. It also doesn't have good balance at low volumes.

So I bought the Emotiva UPA-2. Fast forward to today. I setup the UPA-2, turned the power on, and to my disgust - there was a very loud/audible humming which corresponded with the output level on the UPA-2. At first I thought it was my generic monoprice cable causing the problem. But then I tried connecting both my TV and iPod straight to the UPA-2 and... the humming was gone. Could it be possible that UPA-2 doesn't work well with a tube preamp? Either way, I disconnected the thing and I'm back to using the Decco only.

I really need some advice. First, is there anything I should try before giving up on the Decco + UPA-2? And second, if it came down to it, I'd rather keep the Decco and look for a new power amp. I'm trying to keep the price under $500 and used would be okay. I don't need anything crazy, the room is only about 12x12. Any suggestions would be greatly appreciated... thanks
koven
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knownothing
1,579 posts
 
That is a bummer. I would contact Signal Path and ask them about potential compatibility issues with the Emotiva. http://signalpathint.com/index.php/Contact-Us/Contacts/ It may very well be an impedance mismatch between Pre (Output Impedance???) and amp (Input Impedance: 47K ohm).

I have had similar volume mismatching issues with an int. amp that does not have a quality volume pot and it can be frustrating. Another amp wont fix this, as it sounds like a problem inherent with your Decco. I would ask Signal Path about that too - but the ultimate solution may be a different preamp and DAC.

Something like a Benchmark DAC1 PRE ($).

Or in a more modest price range - preamps like these:

Antique Sound - Wave Line-One-Vacuum Tube Preamplifier
Parasound - Zpre2 Audio/Video Preamplifier
Emotiva - USP-1 Stereo Preamplifier

and DAC's like these:

Musical Fidelity - V-DAC Digital to Analog Converter
Cambridge - Dac Magic Digital to Analog Converter

Good luck!
blindjim
3,092 posts
 
Hum came after installing the emotiva amp... right?

first try using a cheater plug to lift the ground off the new amp... $0.75.

Second try plugging the amp into a ckt the preamp is not on. Same with other components.

Last thing I can think of is turning the EMotiva amp's plug over (if that's doable) and pluggin it in that way.

I'd try to keep my cable box off the same ckt as the amp.

Good luck.
rwwear
2,867 posts
 
Disconnect the coax/cable from your TV and see if the hum goes away. You may need an isolator for the cable TV.
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