I wanted to get back to this List, to let you know how things are turning out.  

I bought a used RME hdsp 9652, and a Frontier Tango24 for d/a over ADAT.  It is working pretty darn good.  I can easily run with 64 sample buffer, no xruns (may try lower), and my digital piano app says my cpu performance factor is 67/100, highest it's ever been.  And as some of you said, it actually does seem to SOUND BETTER... :)  The piano sounds softer and nicer, as if the hammer felt were softer.  The lowest bass notes sound great; low A played with next octave A sounds better together I think. The optical isolation between cpu and Tango has gotten rid of the bad interference/hum I had.  I have one amp that can use 1.4v input sensitivity, and 2 others that only can use .7v, but the Tango allows me to set its individual outputs accordingly.  There is still very slight hiss, which I guess is unavoidable, but I think I can reduce it by increasing the signal level as much as I can coming from the PC, and turning down the gain some on the amps.  Also, it may help to get rid of my 3 ams (woofer/mid/tweeter) and replace them with just the Crown 1502 for woofers, and a multi-channel amp for the rest (and for surround sound speakers, when I get around to adding those.)  

Thanks for all the help.   I'm happy...
John


On Tue, Mar 7, 2017 at 6:56 AM, Ralf Mardorf <ralf.mardorf@alice-dsl.net> wrote:
On Tue, 7 Mar 2017 06:11:26 -0500, john gibby wrote:
>I like the idea of using the PCIE bus, to minimize latency for my
>digital piano.  But an external (USB) audio interface would introduce
>less than 1ms latency, and might be a good practical solution.

Hi,

I get lower latency with a Focusrite Scarlett 18i20, an USB audio
interface, than with a RME HDSPe AIO, a PCIe audio interface.

For both, my old ASUS M2A-VM HDMI with a 2.1 GHz Athlon dual-core, as
well as for my new GA-B85M-D3H with a 2.8 GHz Celeron dual-core.

The PCIe card not necessarily suffers more from computer emissions,
than gear that is galvanic isolated from the computer, e.g. by ADAT
lightpipes and one or two meters away from the computer, just the risk
is higher that a build in card could suffer from computer emissions.

Class compliant audio interfaces are better supported by Linux, than
other audio interfaces.

All pro-sumer audio interfaces I ever heard, sounded better, than any
onboard audio device I ever heard. If the audio quality of your onboard
audio device is all you need, then you most likely could buy any Linux
compatible pro-sumer audio interface, no need to compare audio quality
of different pro-sumer devices or to buy a professional audio interface.
You still need to take care about other quality aspects. Consider to
read customer reviews, e.g. the power supplies of some external audio
interfaces are known to break.

FWIW on my old mobo the audio hardware didn't share IRQs and on the new
mobo the audio hardware shares IRQs, but I only experienced issues with
my old mobo and the PCIe card.

Regards,
Ralf
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