Tube pre for class d recommendations

I have a Rogue Hydra which is a hybrid Class D and have had it paired with three preamps for extended periods of time and was very happy with all three.  Ayre K-5xeMP, PS Audio BHK and Art Audio Composer.  The latter two are tube units.  I also tried and demo'd 4 other preamps through time.  All solid state which I hated.  

The brightness that still lingers in most Class Ds can absolutely be offset by a tube pre.  I found the stock tubes on the PS Audio to leave a bit of brightness but rolling in a pair of Tunsgram's did wonders.  The stock tubes on the Composer are amazing and will temper that brightness beautifully.  Full disclosure, I am the importer for Art Audio.  

I offer a 30 day no questions asked return policy.  If you don't like it, return it and you only need to pay shipping back to CT.

I believe Rogue has been doing tube pre and Class D power for some time now.

Interesting Ralph.
I have 2 foundation research LC2...one grounded and the other lifted ...done by Ed....that I used. Meaning, I was really giving it the old college try to make it work.

Lifting grounds is not going to do it with the UV-1 since its really hard to ground loop it through the power cord.

We did run into a hum problem with a dealer of ours that was using a Topping amp which is class D. The amp was only $80.00 on Amazon so I bought one but could not duplicate the complaint with his UV-1 or any that we had here in the shop. My best guess is that there was something wrong with his amp but its all water under the bridge so I don't think we'll ever know. Otherwise we've been able to solve all the hum problems we've encountered with the UV-1 except for that one. The dealer sold that preamp and the customer seems to like it a lot.

The UV-1 has an aluminum chassis and a steel bottom cover. It can hum if placed near a power transformer or the like since aluminum does not shield at audio frequencies.

My Freya (now the "vintage" version as it has a hotter output tube section which, alas, the newer versions have tamed somewhat) sounded quiet with the supplied "mystery" tubes, but they were boring so I moved on to new Tung Sols that look great! Also boring...so...NOS Sylvania "chrome domes" and RCAs have been doing the job real well and I’m not bored with them. My power amp is a single ended Had Firebottle HO (yes, a HO...says so right there) with a 6SN7GTB (NOS alleged Amperex) driver tube and I only mention that to point out the synergy of tube types, which means nothing. What does mean something is the fact that tubes are more fun than Class D will ever be...tubes can be looked at, burn yer fingers, and swapped out willy nilly. Class D can stay in my little Ampeg "Porta Flex" bass amp, flying above your head in phased array PA speakers, and in the future perhaps a better toaster, but not in my hifi or guitar amps...no no no. Less heat, efficient power...boring.

owentdc,

     From my experience owning 3 class D amps and those I've heard in others' systems, I believe they all have some common sonic characteristics: very good bass response, low noise floors, good dynamics, are highly detailed from top to bottom and and have an overall sound best described as neutral like 'a straight wire with gain'. 
     The neutrality of class D amps are beneficial since the sound imparted by the preamp, and the sound discrepancies between stock and swapped tubes, are usually easily discernible.due to the amps just faithfully amplifying the inputted signals without any audible sonic additions or subtractions. 
     The variances I've noticed between all of the class D amps I've heard is mainly with treble responses that typically are very detailed but also have ranged from smooth and almost tube-like to a bit overly bright. 
     Fortunately, I've perceived the treble of the 3 class D amps I've owned as detailed but still smooth and, on good recordings, there's even some tube-like euphonic sweetness I hear. 
     I've read some good reviews on your Wyred4 Sound STI-1000 but, apparently, you perceive some treble brightness.
     I've actually perceived more treble brightness from my previous class AB amps (Adcom, McCormack and Aragon) than my subsequent class D amps. 
     I auditioned many good tube preamps  searching for one to sweeten the treble on my high powered ss amps driving my Magnepan speakers.
      This was about 1990 and I recall many tube preamps I tried in my system not sounding as warm and euphonic as I was hoping such as Audio Research, Cary and a few others.
     The right solution for me turned out to be a VTL 2.5 tube preamp but I had to swap out the stock Russian or Chinese tubes for a set of 4 expensive ( $200 at the time) NOS Mullard tubes to get the warmth I wanted.
     Currently, however, I've discovered my system sounds best for music and ht just connecting my main source, an Oppo-105,  directly to 3 class D amps without using any preamp at all.  The Oppo serves as a Blu-ray player, cd player, Dolby Digital 5.1 surround sound processor as well as a dac for streaming internet radio and NAS cd/hi-res files. 
     Sure, this configuration is typically dismissed by fellow A-gon members and others as sub-standard, but I don't mind a little ridicule since it's so streamlined and sounds so good to me.  I also know some are just not aware of the high quality and versatility of the Oppo BDP-105
     You may want to try this first if your sources allow before adding a tube preamp.  If not, I'd suggest finding a good local dealer who'll let you try out some loaner tube preamps to audition at home in your system.     
Tim