unbalanced xlr input (a24) to mytek balanced output

maybe Im getting a true  balanced differential and common XLRs mixed up. Im a little lost. If it is not a balanced differential wouldnt it just be XLRs (really RCAs) connected instead of RCAs?

In the case of the A21 yes, it has true differential XLR inputs. The A23 does not.

However, it’s a trivial thing to adjust for this gain with a sub. The A21 and a sub both have gain adjustments.

A component can have input and/or output circuits that are balanced and differential regardless of whether the rest of its internal signal path is balanced and differential or not. If the entire signal path of a component is balanced, it is usually referred to as being “fully balanced,” or words to that effect.

In this case I’m pretty certain that aside from its input circuits the internal signal path of the A21 is single-ended, but several things in its description, specs, and manual appear to indicate that its input circuits which receive the signals provided to its XLR connectors are in fact balanced and differential. Including a statement in its description that it provides "balanced inputs with discrete circuits and XLR connectors"; the fact that its input impedance is specified as "33 k Ω unbalanced; 66 k Ω balanced"; and various statements in the manual referring to the advantages of balanced interconnections.

Also, while it is true that connecting a balanced output to a balanced input (as you indicated you would be doing in connecting the Mytek DAC to the A21) will often result in 6 db more overall system gain than would be provided by an unbalanced connection between the same components, that is not always the case. It depends on the designs of the specific interface circuits in **both** components. And after looking at the descriptions and manuals of the two components I don’t see enough information to determine the answer in this case.

BTW, I see also that the Brooklyn DAC incorporates internal jumpers that are said to provide the capability of reducing its output levels by 6 db. That may not have any relevance to your question, but I thought I’d point it out.

Regards,

-- Al

Sometimes an XLR input is actually not differential, but there for convenience. The A23 is an example. The (-) pin on the XLR input is grounded.

In the A21 however the (+) and (-) pins are not grounded, each has a 33k impedance to ground and the difference between them is used to determine the output.

In my setup between true-balanced Bat42se and a21 there is no 6db increase via XLR connection, but between my two separate Bat components and other true-balanced devices the increase in volume  is obvious. I doubt the a21 is a true-balanced amp.