Why do most phono preamps lack XLR input even thought cartridges are naturally balanced?

Except with a phono input, you don't gain 6db, as it is an application specific input. It amplifies the difference between the two leads. There is no "differential" output that has 2x the signal level (6 db).

roberttdid

Except with a phono input, you don’t gain 6db, as it is an application specific input. It amplifies the difference between the two leads. There is no "differential" output that has 2x the signal level (6 db).

I do not know what you mean by "application specific input" or why this matter isn’t more clear to you.

My phono preamp gain is adjustable and is spec’d up to a maximum of 68 dB single ended and 74 dB balanced. That seems consistent with my experience.

 To clarify, I can only add the specs for my Ayre P-5xe: the gain for the balanced output is 6 dB higher than single ended out for each of the 3 gain selections. However the gain does NOT change with the choice of RCA or XLR inputs. You should be able to look up the specs and recommended phono cable wirings on the Ayre website in the manual download.  The specs are minimal and no S:N specs are given.

oldears

...the specs for my Ayre P-5xe: the gain for the balanced output is 6 dB higher than single ended out for each of the 3 gain selections. However the gain does NOT change with the choice of RCA or XLR inputs ...

Thank you! Exactly. That’s been one of my points from the beginning of this thread; the choice of connector has nothing inherently to do with whether the circuit is balanced (or not) or differential (or not).

And one of the best places to use differential circuits is in the phono section, for both higher gain and better immunity to noise.

I have a very fine Audio Research PH-2 that is balanced in and out....And it works like it should.........