I remembered that I have a Samson S-phone laying around, which I bought several years ago at an excellent deal. It's a 4-channel headphone amp, which has some mixing and equalization capabilities for each channel.
The Onkyo DVD receiver (DR-UN7), which I use as the center piece for playing DVD-Audio, SACD, and plain CDs, has 6-channel output. Main fronts are speaker-level outs, so I use a Soundgate LOCX line-out converter to bring them down to line-level and then feed them to Onkyo A-RV401 integrated amp, which results in a pristine output on my main front speakers. Center and surround channels come as pre-outs on the DR-UN7.
I suspect that the pre-amps in the DR-UN7 are rather weak and noisy, so I would like to attenuate them as much as possible and boost them externally before sending them to the Yamaha DSP-E492 integrated amp.
Ideally, I'd like to use the DR-UN7 as the source only. If I could figure out a way of tapping the signal from its disc player directly before it goes to an internal pre-amp, that would be perfect, but that would require me to splice up the system, probably... So, instead, I'd like to try main volume attenuation + external pre-amp.
So can a headphone amp, like Samson S-phone, be used for boosting the signal from DR-UN7 before it's sent to an external integrated amp, like Yamaha DSP-E492?
