Oppo bdp-83 straight to power amplifier

It can be done carefully, but there is no soft start feature, the volume comes on where you left it last.

not recommended.

Yes, you can do it. It does turn on where you last left it, so be careful with volume. I would suggest you turn on the Oppo first, turn down the volume, then turn on the amp......

BTW, I think the volume control is in the digital domain, so you will lose resolution as you turn down the volume.

I'm using a mod'd Oppo DV-970 direct to amp and it works great.

Any problems with sufficient gain?
Going to be using it via a PS Audio HCA-2 power amplifier.