Okay to use RCA adapter on a fully balanced amp?

My amps are fully balanced and there is no issue with using them with RCA to XLR adapter. 

The adapter grounds one of the differential inputs to ground and then the amplifier behaves like a single-ended to the differential converter.

The gain of the amplifier does not change and it requires 5V input to get it to full power. This is an issue with standard RCA 2V outputs as 2V will get you less than 1/4 of the amps rated output power.

This is why I recommended to most my customers to get my active RCA to XLR converter that @evank refers to above. With 8dB of gain, it takes 2V up to 5V.  

@orchardaudio Most preamps can do 5Volts easily as long as the input impedance of the amp isn't an issue! My recommendation is thus to simply try it.

@atmasphere I agree in this scenario, the input impedance on my amps using an RCA to XLR adapter would be 22k.

@orchardaudio that will be tricky for a lot of tube preamps. Our preamps can drive that no worries, but our preamps are balanced so its moot...

OK, so I was totally wrong to doubt the amp’s description - it is indeed truly balanced, albeit with a rather low sensitivity (5 Volts is a lot to ask)! Sorry about that. An RCA-to-XLR adaptor will be a perfect solution, so long as you have enough upstream gain to get where you want in volume.