Phono Pre-amp with XLR

Tdaudio, if the preamp is differential, but you only drive one input, perhaps the non-inverting input (with the other input being tied to ground, where the minus output of the cartridge is also tied), the gain will be exactly the same as if you were driving both inputs, assuming the source to be the same cartridge in both cases. What you loose is the cable immunity (tonal neutrality) and rejection of noise in the cable.

While I do think that true balanced phono amps are a good thing. This because with MC the signal is very low and you can use all the help you can get in amplifying the signal with getting increasing the noise level. However making a balanced amp is more expensive since you will need almost twice the components.

Also in pro audio almost no equipment is truly balanced they just use a RCA/XLR conversion at the in and outputs of amps. This is done so they can use longer cables.

In home audio you will often see the same. XLR inputs the an IC that converts the signal into non balanced. To me this is pointless since almost no one uses long cables in home audio. If a non balanced amp has XLR inputs I think it should say this in the manual. Otherwise people might think that any amp with XLR inputs is also balanced.

quote]However making a balanced amp is more expensive since you will need almost twice the components.[/quote]

It is more expensive but you do not need twice the components. Maybe 50% more if you are talking tubes, maybe not even that if you are talking solid state.