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.

@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.
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.
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. 

The hum you read about was not inherent in the preamp, but was caused by the higher output impedance of the preamp combined with poor interconnect cable layout between the preamp and amp. Once the guy on the stevehoffman site got the layout right, the hum was gone.

While it does have an XLR output, it does not support the balanced standard. If it did, the hum with the interconnect cable layout would not have been an issue.
Reach out to Andy Tebbe of Backert Labs. He's terrific to deal and work with and I'm sure he will addresses this concern and any other questions you have. All the best.