PS AUDIO PERFECT WAVE MKII

Great responses so far. The preamp/direct question seems to be one of those things that can be very unpredictable and influenced by impedance matching and many other factors. I'm willing to bet that the MKII > Amp can be bettered by a very, very fine preamp but in my situation it's not a margin I'm willing to pay $5-10k to explore.

I used it with a preamp, which I much preferred. Amp-direct, the DAC sounded a bit shrill and the soundstage collapsed. Even Paul McGowan, the head of PS Audio, who initially claimed amp-direct sounded best, ended up buying an Aesthetix Calypso and concluded that his system sounded much better when that preamp was inserted between the PW2 and his amp.

It all depends on your preamp, system synergy and personal taste. Personally I much prefer with my VAC SigMKIIa pre in the chain when I had a PWDMKII.

My brother has a DirectStream and is using his McIntosh preamp in the chain.

Also if you are using a preamp, turn volume on the DAC to 100% for best results. Volume control is in digital domain so truncating bits if not 100%

Knghifi, according to Ted Smith of PS Audio,it does not matter where the volume level is,the DS will not lose any bits digitally.

From PS Audio forums. Ted Smith quote below...

The DS doesn't loose bits digitally no matter what the volume is set to. Still there's an analog noise floor so if you never have the volume set above, say 60, you'd be better off to use the 20dB attenuator and have the volume up nearer 100. Since the 20dB attenuator is implemented passively in analog it lowers the analog noise floor by, well, 20dB.

Also, FWIW, there's nothing special about 100, e.g. 93 (or any volume setting that works for you) will not cause any less accuracy anywhere in the DS than you get with the volume at 100.