If you looked 7 post up I don't have to phone them, I got the answer for you already from the head of technical at Oppo above.
Oppo's email to me, the reason is because of "bit striping" at volumes below 80, that's why it's not recommended, not because it makes noises when it's played direct to poweramps.
Any tech will tell you that noises such as you explained you are getting are not conducive to a cdp that's in healthy condition.
The only reason your Parasound P7 pre is not passing it through is because it's a capacitor coupled preamp, and capacitors block dc spikes.
As I said if you were to use a dc coupled preamp such as Pass Labs, Krell ect, you will find the noises are back again, just like they are when you go direct to the poweramp.
Cheers George
Oppo's email to me, the reason is because of "bit striping" at volumes below 80, that's why it's not recommended, not because it makes noises when it's played direct to poweramps.
Any tech will tell you that noises such as you explained you are getting are not conducive to a cdp that's in healthy condition.
The only reason your Parasound P7 pre is not passing it through is because it's a capacitor coupled preamp, and capacitors block dc spikes.
As I said if you were to use a dc coupled preamp such as Pass Labs, Krell ect, you will find the noises are back again, just like they are when you go direct to the poweramp.
Cheers George