As you said you were comparing two preamps, you found one better than the other, as you said the Benchmark has it’s own internal preamp.
What’s discussed here, is going direct from a dac’s "output buffer" (that has no internal preamp), direct to the amp/s using the dac own digital domain volume control, andtherefore having no preamps at all in the signal path.
Basically the preamp section of the Benchmark 3 is replaced which the much more substantial Hegel preamp and the Benchmark DAC running in DAC mode improves performance aswell.
Maybe, a passive should have been tried running in DAC mode
Cheers George