Anyone know what the “maximum input level” in Volts RMS for the balanced inputs?
It looks like the Adcom’s GFP-750 manual does not state this information, so I’m not sure how anyone would know it. Here’s a good rule of thumb; most balanced analog pro-gear has an input clip level of +24 dBu. You definitely don’t want to exceed that, and it’s doubtful your equipment could even provide such a high output. I still stand by the old standard of supplying a +4 dBu (or 1.23 volts) output signal (@ 1 KHz) to an analog balanced input. This then allows +20 dB of headroom on the balanced analog input. The pre-amp circuitry should then provide the gain needed to feed the power amplifier.