Hi Doug,
If an analog multichannel pre-amp will suit your needs, I recommend you check out either the Sony ta-p9000es or the Arcam C30 fitted with the optional multichannel module (note: the current model Arcam C31 does not have multichannel capability). The Sony can now be had used for around $500 and the Arcam at around $1,000 or so.
Both are now discontinued but are great-sounding pre-amps for both stereo and multichannel music.
Of course, neither of these units will decode surround from your other surround sources like cable box/DVR or video game console, but should be a noticable upgrade compared to your Onkyo AVR as pre-amp.. -jz
If an analog multichannel pre-amp will suit your needs, I recommend you check out either the Sony ta-p9000es or the Arcam C30 fitted with the optional multichannel module (note: the current model Arcam C31 does not have multichannel capability). The Sony can now be had used for around $500 and the Arcam at around $1,000 or so.
Both are now discontinued but are great-sounding pre-amps for both stereo and multichannel music.
Of course, neither of these units will decode surround from your other surround sources like cable box/DVR or video game console, but should be a noticable upgrade compared to your Onkyo AVR as pre-amp.. -jz