How to go from RCA to XLR?

Sounds like you need a single ended to balanced transformer like the Jensen model.

With designs that I am familiar with, feeding a balanced differential amplifier input with a single-ended signal will only mean that you have to turn the volume control on the preamp up a bit higher, by 6 db. It will not affect the maximum power output of the amp, only the volume control setting on the preamp that is required to reach that maximum output.

I suspect that the person you spoke to at Aragon doesn't know what he is talking about. Or else their design is very unusual in some respect.

A transformer such as Rwwear suggests will get you back most of the 6db, if that matters, but a quality transformer is likely to cost significant $, and even a good one may still have subtle sonic effects.

Regards,
-- Al

Noslop, the news you got is erroneous! If one of the phases is not present, the gain of the amp may be reduced by 6 db, but there will be no loss in power! Whoever told you that really has no idea how this stuff works.

Yes, I suppose any circuitry added will have a sonic signature but the Jensen transformers are the same one's Audio Research and Rowland use to make their products balanced. They claim the sound is better than truly balanced but I don't know. It's certainly much cheaper at around 200.00.
Atmasphere, isn't losing 6db of gain the same as losing half the output of the amp or more?

Atmasphere, isn't losing 6db of gain the same as losing half the output of the amp or more?

No. That's the basic point that both Atmasphere and I were making, which the person at Aragon apparently doesn't understand. Losing 6db of gain just means that the volume control on the preamp has to be turned up a little bit higher (6 db), to drive the power amplifier to the same maximum output power level that it would otherwise have reached at a 6 db lower setting of the volume control.

There is absolutely no difference either way in the amplifier's maximum power output. The only difference is in the volume control setting at which that maximum happens to be reached, which is a completely inconsequential difference, except perhaps in an extremely rare situation in which the preamp and power amp are severely mismatched in terms of gains and levels.

Regards,
-- Al