Balanced vs RCA preamps

@atmasphere 

Clearly with such a long distance for a cable, a balanced XLR cable makes sense.  RCA connect going out that long is never really a good idea. Interesting speakers horns are deserving of a look next time I buy a speaker

For the most part it's purely bragging rights.  XLR connections when fully and correctly implemented can reduce noise and eliminate ground loops.

In some circumstances this can be huge, but for most of us it's minor.

Also, as others note, if you are using very long runs to other devices with truly balanced inputs this is helpful in ensuring there's no noise pickup along the way.  Some devices, like some Parasound amps as an exmaple, have XLR inputs as convenience but they are not balanced inputs, so you don't get  the benefit of a long run with less noise.

To the OP, Balanced Audio Technology (BAT) makes several tubed preamps.  Most of their models are solely balanced.  Heck, "Balanced" is even in their brand name.  However, the model VK-80 has two balanced inputs and three RCA inputs as well as balanced and RCA outputs.  If you are looking to buy a used preamp, their model VK-33SE is the predecessor to the VK-80 and has the exact same inputs/outputs.  I owned the VK-33SE and can speak for its sonic excellence as well as build quality.  I made a step up in the BAT product line and now have the VK-90.  Highly recommended as a brand of excellence in all regards.

Back to the Spatial Audio Lab Raven tube Preamp it is fully balanced and dead quiet. If you don’t need a lot of output power their suite (mono’s & pre) punch far above their cost. Like wow….Ahyho… 

Years ago I was yacking with Mr. Internet, Kevin Deal (he does know his stuff) and he said on the RCA/XLR question that component build quality is what matters. 

Recently I swapped in/out RCA/XLR cables from source to pre and from pre to monos. My data set of one could hear no difference. As for my build quality, that’s another matter. Lifetime guarantee? Who’s lifetime?

To drop noise floor, I prefer balanced.

For checking out tube amps including flea watt which usually have a higher noise floor, I’m indifferent.  I’m mostly concerned with the sonic profile offered by tube amplification