Backert Labs Rhumba preamp

I am thinking of going to an active line stage for sometime now. I have a separate thread for that and people have suggested some good choices. The reason for this thread if that, while I have all along said that  don't want tubes in the system, a few have convinced me that I should try tubes in the system, especially with ProAcs.
With that said, I researched a few tube preamps, that have XLR out and the Backert Labs Rhumba is the one that has only 2 tubes, which makes me comfortable to "deal in tubes".

I would like to hear from Backert Labs Rhumba owners who moved from Solid State preamplification to this preamp. What are the differences you heard? Any improvements?

I read a review on the Stevehoffman forum and the user mentioned that there is a "hum" in this preamp. This bothers me and hence I decided to check on this forum, if anyone has experienced this with the Rhumba in their system. One poster on this forum also confirmed the "hiss":

So I was wondering, if there are any users who have recently purchased this preamp and what is their experience with the hum/hiss issue.

BTW, I blame Ralph of Atma-Sphere, Almarg  and my dealer for making me consider tube amps :-) Can't believe I am creating this thread.

Definitely no hiss or hum is inherent in the excellent Backert Rhumba preamp. I have been running mine for almost a year now.

It’s wonderful. Crazy good sound with a pair of CBS 5814a tubes. 

I know the Backerts having had the good fortune to visit their home a few times to have my gear modified.  All proprietary designs as Bob worked on cj preamps for many years and developed his own board to open up the sound and enhance the dynamic response of the stock unit.  Like all of the finest designers of audio gear, his work emphasized maximizing the design of the power supply circuitry.  He holds patents on his power supply designs prior to launching Backert Labs.

Bob is one of the finest people I have ever associated with in my 40+ years in audio. 

Sorry I can't relate personal experience with the Rhumba but I can unconditionally attest to the character and talents of the designer.
@david_ten , will try to reach out and discuss with them.
@atmasphere , I wanted to make sure that it was not really a generic issue. Backert Labs do mention that all their preamps are single ended, with XLR out. I don't think, for that matter, that my Parasound A21 is fully balanced. But when it is connected to the preamp via XLR, it sounds amazing.
@1markr ,You have a beautiful setup. I see that that you even have tube power amps. Did you compare the Coincident Line stage with Backert? Good to know that you don't have issues with the Rhumba. Wonder why not many folks are using it. Does your Coincident amp have XLR in? Did you get a chance to compare the Backer Lab connected to the amp via XLR Vs RCA?
@hifiman5 ,Thank You for the reference.
@milpai  thanks for the system compliment!  At the time I was looking for a preamp, I did want to try a Statement preamp, but none were popping up, so I decided to buy the Rhumba from a dealer instead (something to be said about a 30 audition policy!). 

Anyways, I loved what I was hearing, and obviously it didn't go back. Haven't heard the Coincident Statement, unfortunately.

The amps don't have XLR inputs, so I do not use the balanced input or output of the Backert.

As someone in the same boat as you -- solid state guy looking to add a tubed pre for the first time -- thought I'd chime in FWIW.  My goal is to introduce some of that tube magic into my system with as little or no sense of a loss of transparency or bass control.  The Rhumba is also one of the top three on my list, and given what I've read it's really hard to see going wrong with it.  But the other two on my list are Don Sach's SP14 pre and Ralph's MP3.  The fact that the MP3 does away with coupling capacitors intrigues given my concern about compromised bass.  BTW, there's a very nice, almost new MP3 available now on US Audio Mart that might very well be on its way to me now if I had the scratch. 

Anyway, since we seem to be going down the same road I just thought I'd share what I've been looking at.  Best of luck!