Balanced vs RCA preamps

Just because you have balanced input and out puts does not mean the unit is full balanced! A very large part of the pre amp market is not fully balanced. Even though they have the connections.

True, @68pete , but I bet that almost every manufacturer that puts a piece of gear out with a truly balanced circuit comes out and says so in the owner's manual.  

First, as always, thanks to "atmasphere" for his input.  

I would add that there are a number of considerations to address when buying a preamplifier.  Connectivity being only one.  Your system arrangement and placement of components is another important part.  A good standard practice is to keep loudspeaker cables as short as practically possible. That leaves you with the interconnects.  Any well designed & engineered single-ended preamplifier with a low output impedance (~200 ohms) should be capable of driving long runs of interconnecting cable. Choosing an interconnect cable shouldn't be left to chance.

For several years I used 30' runs between my preamp and my mono block amps with no hum or any other issue.  My current arrangement in a new home is much different and my interconnects have stayed the same, but I just shortened them to about a meter in length. My mono block amps do not have balanced connectivity.  If they had I may have tried both single ended & balanced interconnects especially if the amps were truly of a balanced design.

I would encourage you to home demo any preamplifier that you are considering before you purchase.  Preamplifiers are a very important component in all things hi-fi. Afterall, it's all about the sound. 

Happy hunting 

atmasphere

The reason to use a balanced connection should be to eliminate ground loops and cable artifact. 

I'd argue that noise reduction is the primary benefit of truly balanced circuits, which can offer high CMMR.

A proper (AES48) balanced connection will do that. Its worth noting that a lot of 'high end audio' balanced equipment does not support AES48 even though it's balanced.

Balanced equipment that isn't AES compliant isn't necessarily "improper," it's just different. For example, the balanced ARC gear isn't AES compliant, yet using the balanced connections yields improvement that you can measure and hear.

@68pete "Just because you have balanced input and out puts does not mean the unit is full balanced!” +1

XLR isn’t only balancing solution possible! I designed “balanced interconnect” by adding out and in fully isolating ground transformers, typ 50Ohm unbal. <=> 600Ohm bal. systems with RCA/DIN unbalanced outs and ins with excellent results! 

"it is not a good idea to base your decision on which preamp to buy solely on the basis of balanced outputs.  First of all, they do not exist for tube equipment"

Perhaps some clarification regarding Balanced Tube Line-Preamps is in order...

I am currently running a Balanced Tube Line-Preamp (Audio Research Ref 6SE ) into a Balance SS Amp (Ayre V5).  My understanding is BOTH boxes are fully-balanced (that is, they are not simply using XLR connectors, with single-ended circuitry).  The cables are XLR terminated (High Fidelity Cables).   

From the ARC marketing brochure: the 6SE is a fully-balanced, Class-A design with zero feedback."

If the hifi lore is true, the founding-fathers of both companies, William Zane Johnson (-2011) at Audio Research and Charlie Hanson (-2017) at Ayre strongly preferred designing balanced circuits for their equipment. 

With that said, both boxes have single-ended connections as well to appeal to a broader marked.  Why? Many sources are single-ended (ex. my Zest phono-pre is single ended output only, so the cable going into the ARC line-pre must be single ended).

Bottom line... Yes, you can buy a high-SQ Balanced Tube Line-Preamp that also has single-ended connections.

(my apologies if this was covered by prior replies, as I currently do not have enough time to read the full string)

Happy Hunting!