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.

The output impedance of Rhumba is a low 75 ohms. Based on what @almarg once told me, this will match with your Bryston 4B3 amp, which has an input impedance of 30k Ohms.
Check this thread:

Bringing this thread to life to find out from current Backert Rhumba users on what is the volume position on the dial that they generally use for listening?

My story is that I used to use it 90% of the time between 9 and 9:30 position and it sounded fine. Very rare SACD recordings used to allow me to bump it to 10 or even 11 o'clock position. But recently came across this thread on Oppo UDP-205 that I use as my DAC. Apparently, setting the volume control setting to "variable" you can go down to 70 (from a max 100 = Fixed), without loosing the resolution. I experimented with the setting and I have set it to 90 now. With this I am able to get anywhere between 12 and 1 o'clock position comfortably. Some SACDs might allow me to go to 2 o'clock position - is my guess.The best part is that, this gives the music more texture and I can hear better nuances. The system sound more natural now and what I used to think as "fine" before, now sounds more strident. Bob in that thread discusses how we do not lose resolution by lowering the output level to a certain point.

TBH, I never used to like the idea of a DAC with "variable" volume control. Suddenly I am ALL for "variable" volume control in a DAC, as long as we do not lose resolution. If at all, with all the "loudness war", we only stand to gain more resolution (not in the recording, but output of playback). Have you all experienced this? I am thrilled to say the least.