Balanced vs RCA preamps

Will someone explain fully balanced.

Ground loops can exist even with a balanced connection. You may have to lift pin one.

Tubes or solid state can be balanced it just depends on how many tubes you want to use or if you want transformers.

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.

@mammothguy54 You might be interested to know that one of the founders of BAT, Steve Bednarski, was a customer of ours before BAT, and owned one of the first production Atma-Sphere MP-1 preamps.

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.

@wsrrsw If the balanced equipment doesn’t support AES48 you may well have heard no difference or even a degradation compared to the RCA connection.

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

@cleeds Unless it doesn’t... I’ve seen some (shall we say) sophomoric ’balanced’ products offered in high end audio that had almost no CMRR at all. -Almost as if the designer didn’t understand what that Common Mode Rejection was all about.

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.

This is true. But you’ll hear cable differences, the system will be subject to ground loop possibility and you won’t be able to drive long cables. These problems were solved over 70 years ago! Imagine a recording studio where you may have 20 different audio devices connected together (although usually not all in the recording chain at one time). If you have a ground loop buzz it could take weeks to sort it out! Ground loops are an audio menace many audiophiles have dealt with; AES48 prevents that happening.

Imagine not having to worry if an interconnect cable is going to sound right- just plug and play with no worries. That too is a benefit of balanced lines if done right (usually you have to support being able to drive a 600 Ohm load).

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!

@westcoastaudiophile +1 The venerable Ampex 351 tape machines (which were used to record a lot of the RCA Living Stereo catalog) were internally single-ended but used input and output transformers to interface with balanced connections.

atmasphere

... I’ve seen some (shall we say) sophomoric ’balanced’ products offered in high end audio that had almost no CMRR at all ...

That's not surprising - there's quite a bit of mediocre audio equipment on the market. But to argue that balanced components that do not observe the AES spec are somehow "improper" is misguided. They can still offer potential advantages over single-ended components, including improved CMRR.

... you’ll hear cable differences, the system will be subject to ground loop possibility and you won’t be able to drive long cables ...

I'm not having those problems with my mostly ARC system, which is not AES compliant.

As an aside, I'd wager there are balanced, AES compliant components on the market that are easily bettered by some single-ended gear. As is often the case, the implementation is as critical as the topology or technology.

Balanced is only good if you prefer less noise.

A word of caution. Just because there’s an XLR connection does not mean it is a truly balanced circuit. I’ve seen many implementations where it’s actually a single ended circuit transmitted via XLR connectors. 

@rwwear — is that sarcasm?