Two issues with a new build

Hi gang!
 
So I just finished (does one ever finish?) building a new DAW!
 
For the curious, it is an i7-4780 locked at 4GHz on a Z97 motherboard with SSDs for the OS and Apps, and Kontakt and Toontrack libraries. Spinning SATA3 drives are used for all other data, and other libraries and sound sets, and for projects and project audio. The lack of PCI slots forced a switch from my trusty Dakota/Montana to a USB2 connected Presonus 1818VSL.
 
So far I can run with insanely low latency all the way around (64 ASIO buffers, roughly 3mSec measured round trip latency.)
 
The converters in the Presonus are better than I expected, and my only real complaint is the lack of control via their VSL program. I do miss the Frontier Design Control Panel!
 
---End of review / beginning of help request---
 
1) I am unable to use external inserts, as soon as I select any input (analog or S/P-DIF) as my return I get a very harsh noise. I've tried every combination of clocking, because that's sort of what it sounds like, but I am unable to get it working. I can't even measure the delay, which is probably a clue, but I do not know what it means.
 
2) My Tranzport is not working correctly. Several  buttons no longer function. It was working correctly when I disconnected it from my old machine a couple weeks ago, so I'm wary of assuming it is a hardware problem. I did install the Tranzport driver using both Win7 compatibility and install as admin and saw no warnings or errors.
 
Anyone have any ideas on either one? I am stumped - although as I type this I realize I should have installed MIDI-OX to test the Tranzport. Will do so now and report back if I learn anything.

Thanks all!

Just some ideas to get some more data points for troubleshooting.:
 
- Do you get the same noise whether anything is connected to the hardware input for the selected return or not?
- Does buffer size have any effect?
- When you say you've tried every combination of clocking, does that include syncing to external clocks either as master or slave? If so, you might try setting it to use its internal clock, and disconnecting any digital I/O, even though you're seeing the issue on analog inputs, to.
- What if you create a hardware loopback via either analog or digital patch? Do you get a clean signal from that return?
 
Interesting to hear about the low latency, incidentally. I didn't think the Presonus was capable of a total RT time that low. I looked hard at it when I was shopping for a new interface the last time around, and all the reports I read seemed to indicate that it had a high "hidden" latency component that I attributed to the USB interface. But maybe it just needs a high-spec host machine.
 
Dave

Don't rule out the fact that this is a new device and could be defective. If possible return for exchange.