Backert Labs Rhumba preamp

@milpai  @hifiman5   
the version i upgraded from isn't all that important, simply because v1.2 is better than v1.1  
If you are asking ,for example whether Rhythm v1.1 is better than its cheaper and latest Rhumba Extreme v1.2, that i have no answer as i didn't A/B audition it before. 
What i hear is an overall enhancement by about 10-20% in every sonic attributes, going from Rhumba to Rhythm. i.e sound stage, clarity, dynamics, palpability, airyness, details, transparency and speed too. i'm not good in describing the sonics but it's definitely noticeable improvement.  
Another good thing is Backert Labs preamp are responsive to tube rolling, even though i don't like the addition cost involve with NOS tubes $$$
you may wish to discuss more in depth with Andy about new enhancement in the later versions. 
thanks all
-phil 

@milpai 

" Does tubes make this kind of music sound "slow and syrupy?"

I can tell you from my experience with the Rhumba 1.2, and using the excellent CBS 5814a tubes, your statement is about as far from the truth as can be.  This is no vintage Conrad Johnson preamp!

I have also used close to a dozen other tubes in the Backert, and never did it become slow and syrupy.... warmer, sure, less detailed, sure, but slow.... never!

@1markr ,I was not talking about the Backert. I was talking about "tube preamps" in general. I would not like to loose the pace and clarity of my system. Warmth - no issues - I was told that ProAcs are meant for that.

Hello - nice to see this thread, we thank milpai and the rest of you.
Something above referred to "the higher output impedance of the preamp" .... actually the Rhumba 1.2 preamp has an output impedance of less than 75 ohms, which is quite low. It allows the Rhumba to mate nicely with any power amp you might select.
Thanks again and please don't hesitate to write us, or call if you have any questions.
-Andy Tebbe
Backert Labs

I have now lived with the Backert Labs Rhumba 1.3 for about 4 months and thought I would give my feedback on this preamp. First I should acknowledge that this is a preamp that has ALL the traits of my TVC (sold off), AND adds dynamics that I only found out after adding this preamp to my system. My ProAcs sounds the "full range" that they are.
My biggest worry was the loss of transparency if I went active. On first listen  thought that I had lost transparency, only to immediately realize that the transparency is still there, but I was not used to the extended low end that this premp produced in my system. The highs are also more airy than the TVC. Contrary to what I feared, this preamp adds "life" to discs that have excellent dynamic range. I say this because the CDs that are a "loudness mess" sounded fine with the TVC, but the well recorded CDs (example Hobo, Sara K) did not sound as impressive as they do with the Rhumba. I can say this NOW, because I have now experienced how these CDs should sound like. I have a feeling that a TVC would sound great with a tube amp and a super sensitive loudspeaker. In my system, it sounded very good, but nothing close to the magic that the Rhumba 1.3 is doing.With the Rhumba 1.3, I am enjoying my music collection as if I purchased them all new again. At my listening position I can actually "feel" the bass that it produces with my ProAc D48. This never happened with the TVC. But again, I should not blame the TVC for that. If anything I have to blame myself, because I was always worried to take the volume past 18 (of the 24 positions) on the TVC, fearing that it would not sound good. My gripe about this preamp is that CDs that have messed up recording (dynamics) are played as-is, without making them sound good. Example is John Mayer Continuum CD. It sounds pretty loud at 9'O clock position and it does not sound as impressive. I always thought of tubes as "thick syrupy" sound. Fortunately this is not true. Some "brittle" sounding CDs still sound bright in the treble range.This preamp comes with the new issue of Mullard tubes. They sound pretty good. But Thanks to @almarg. I have replaced them with Gold Lion tubes for the added midrange magic and extended dynamics at both end of the sound spectrum. Vocals sound so real with these tubes. Of course, with the new preamp, I had to reposition my loudspeakers for the best possible sound. Thought I never missed remote control for the past 9 years that I used the TVC, I love the remote volume control. The remote has only 2 buttons, but the weight is substantial. The tube replacement cover is pretty neat. I used to keep it open while listening to the system, for the first month. But I was told that this premp has the appropriate design to vent out heat and I need not keep the cover open.All in all, I am super happy ( as if you cannot make that out from above) with this preamp. Sorry, if it sounds as if I was advertising this preamp - but no, I am not. I am thrilled with what it has brought in my system and listening experience. Thanks to Ralph, Almarg and my dealer who pushed me to get a tube preamp. And thank you to all the Rhumba users who provided me with their feedback.