Well... I was going to title this the Ultimate UpTone Audio USB Regen Review (because it is) but then someone would probably disagree and cause a fuss or start Googling "Ultimate USB Regen" thinking this is a new model (which it isn't).
I'll probably cause a fuss anyway (just like when I dissed the nCore) but I have to go against accepted wisdom and say the USB Regen was a step back in quality. (insert standard boiler plate disclaimer here)
My system has matured over the last few years. The sound is slightly warmer than neutral (musical), harmonically even from top to bottom and images like crazy. There was a meeting of the Tucson Audiophiles at my house Saturday afternoon and everyone agreed the stereo sounded great.
Frank Alles, senior editor of Stereo Times
was over and sent me a nice note:
"The Salks sound really smooth and rich. Plus I thought the imaging was impressive--you got a wide soundstage with great depth and precise localization of individual instruments. Congrats!"
Electronics are by Van Alstine - Fet Valve Hybrid pre-amp, Fet Valve DAC, Synergy 450 Amp.
Speakers are the Salk HT2-TL featuring handmade mesquite veneer and a solid mesquite 1-3/4" thick front baffle.
The music server (Win7 + JRiver) has a Paul Pang USB card powered by an Acopean linear power supply, the SSD is powered by an Anker battery.
The DAC doesn't have a USB input so I use a KingRex UC384 (firmware updated and with current drivers) powered by a second Acopean linear power supply.
There are a bunch of Felix's in use too.
All the regulated linear power supplies and battery isolate the USB pretty well so if the USB Regen does anything wrong I will hear it.
Like anything digital, it takes a while to get a handle on what is happening, first impressions can sometimes be wrong so I listened to a broad range of music:
Ella and Louis
Doug McCloud - Brand New Eyes
Frazey Ford - Indian Ocean
Bela Fleck and the Flecktones - One Flew Over the Cuckoos Nest
Mickey Hart - Planet Drum
Richard Thompson - Still
Rickey Lee Jones - Naked Songs
Rodrigo Y Gabriela - Rodrigo Y Gabriela
Vienna Teng - Aims
Robert Plant - lullaby and...The Ceaseless Roar
And finally I used 3 power supplies with the Uptone Audio USB Regen:
1.) stock switching supply
2.) Breeze Audio linear power supply
3.) Poseidon's Voice Katalyst 5v linear regulated power supply
I ended up using the Katalyst, it is the best of the bunch and did the least damage.
So what didn't I like? The Regen smeared the imaging, 3-dimensional images were now spread wider, sometimes speaker to speaker. Points in space became blobs in space. The sound with the Regen was fine, it did no harm. I can see why some reviews even mention an increase in bass, I think there is a slight increase in volume. I experimented by tweaking the volume up just a hair when the Regen was removed and a lot of the differences disappeared, except for loss of image specificity.
Hardware with a lot of line noise like laptops and music servers using the motherboard USB output would probably benefit from the USB Regen but in my experience adding another layer to a tuned system mucks things up. My recommendation is try before you buy.
My findings dovetail nicely with a review of the UpTone Audio USB Audio review in What's Best Forum that has measurements (highly recommended):Review of Audioquest Jitterbug and Uptone Regen USB Conditioners