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Backert Labs Rhumba preamp

Hello,
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":
https://forum.audiogon.com/discussions/backert-preamps-any-users

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.

Thanks!
128x128milpai
axo0oxa
98 posts
 
With the original Rhumba 1.1 you needed to reverse the speaker polarity and the XLR were not truly balanced. The current model, Rhumba 1.2, both of these design issues have been changed. With the Rhumba 1.2 you do not need to reverse the polarity at your speakers and the XLR line in is now balanced. The Rhumba's sound is very transparent, detailed and dynamic. You can fine tune the final sound of your system by tube rolling, which is a lot of fun. It's ability to create a wide and deep sound stage is second to none. I really am 100% satisfied with the Rhumba 1.2 preamplifier. It is a line stage, there is no phone stage. The unit does have a HT pass through, which is a great feature for people who plan on using this in their multi-channel set up, and the preamplifier has a second pair of line outs so you could run dual subs along with your main speakers if you choose to. I cannot say enough positives about the preamplifier.
milpai's avatar
milpai OP
2,402 posts
 
@axo0oxa ,
Yes, I spoke to Andy about the polarity and he did mention that it was correct polarity with the new models. But he did not mention anything about the "true balanced" design for XLR. In fact, if you go to the following page, it mentions " The Rhumba has 9dB of gain (we can adjust this to suit your specific system) and is single-ended".

http://backertlabs.com/press-release/

So, I am not sure the difference between "Balanced" Vs "true Balanced" that Ralph often refers to.
I am hoping that the Rhumba is much more transparent than my TVC. I am assuming that, it being active, it would naturally sound more dynamic. I do not have a turntable, so phono stage does not matter. But Andy mention that they are coming up with a phono stage later. HT pass through - again it is of no use to me. I would rather have that converted to another XLR IN, if they do it.
Thank You for sharing your positive experiences with this preamp. I found the following instragram message from Backert Labs that is interesting:

https://www.instagram.com/p/Bg7qbLqBEii/
axo0oxa
98 posts
 
From my conversation with Andy, in which I did specifically inquire on this issue, his response was that the XLR is a "true" balanced connection with the 1.2, if that helps. In my opinion, if you are using quality interconnects and your run is not abnormally long, a typical meter interconnect, then a balanced or unbalanced connection is not going to play a big difference in sound quality. What is nice about the balanced connection is how positive the connection is, it really snaps into place.
atmasphere's avatar
atmasphere
11,841 posts
 
So, I am not sure the difference between "Balanced" Vs "true Balanced" that Ralph often refers to.
'True balanced' is not a thing I say so much as I harp about supporting the balanced standard.  The circuit does not have to be balanced to do that properly- it can be single-ended as the Rhumba is, and use an output transformer as the Rhumba does. Transformers can drive balanced lines quite well.
In my opinion, if you are using quality interconnects and your run is not abnormally long, a typical meter interconnect, then a balanced or unbalanced connection is not going to play a big difference in sound quality.
The whole point of balanced line is that the interconnects don't have to be expensive (which might be the same or not as 'quality'). What this means is that you have the same benefit if the cable is 6" or 60 feet, which is to say it will sound right and cheap cables should sound the same as expensive ones, regardless of length.

bdp24's avatar
bdp24
9,821 posts
 

Tim de Paravacini uses transformers to provide the two pair of balanced/XLR outputs on his EAR-Yoshino 868L line stage (two pair of unbalanced/RCA outputs as well). Only two 7DJ8 tubes in the pre amp. Tim does lots of work in the pro sector (Pink Floyd’s studio in London, the tube electronics in the recorder and mics Kavi Alexander uses to make his Water Lily recordings, amongst the highest fidelity in the history of recording. Ry Cooder’s favorite label!), and is well aware of and adheres to the standard to which Atmasphere refers, unlike many designers of consumer gear (excluding Ralph, of course ;-).

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