Hello again,
As an addendum to this , I have proven that the noise i am hearing is NOT appearing on the Analog Inputs.
Therefore i am considering moving forward using the digital outs of this interface for monitoring only.
Since I have no such D/A gear to test with,  I have three questions:

1) can anyone please confirm , who has had this problem, who has then used the digital outs on the affected interface, that the noise does NOT appear on the other digital in/outputs ?

2) Iv never used D/A gear for monitoring in the past, so would a unit like the RME ADI-2 FS work easily with the HDSPe
for output monitoring using just 2 powered speakers (Yamaha HS80s) and Headphones?

3) (i searched for a while but couldnt answer this:) When you plug headphones into the ADI-2 FS , does it turn off
the rear analog outputs (speakers) so i hear only headphones OR speakers? Or do they constantly operate at the same time?

Many thanks, I know the D/A questions are different from the HDSP forum topic, but technically, they
are resolving the initial problem.

Thanks for bearing with me once again~
~Ht

Hi DAW Mastermind,
Thanks for the reply. Yes this card is brand new, from a dedicated physical audio store,
but i bought it as part of my new DAW rig piece-by-piece(over $3000 AU in total), so it was
a few months ago now by the time iv got all the parts together and up and running, which
is outside of the return policy unfortunately (my bad)
However, I would really prefer to use an internal interface, and i am convinced of the majesty
of the HDSPe in the week iv had it up and running, the lack of latency is phenomenal, iv heard
some of these project tracks a thousand times, but this is clearly better, it sounds brilliant,
and soft/firmware works flawlessly (cubase 13), so im just not prepared to give up on it
due to the analog outs.
As suggested above, there is no noise on the Ins, and all of my work is done in-DAW, and i only need
to record one instrument In at a time, so its perfect. I only need the analog Outs due to my desk,
but that wont last forever, i am convinced this is an earth/grounding problem, its just not in a place
(direct from the ports) that i can use a ground lift/filter or similar, and there is no noise on any
mixdowns that i have done so far, so its just the analog outs.
If i can use a box like the ADI-2 FS as i specified above for digital out, then im personally
well prepared to try going down that road, it will meet my needs precisely.
Would the ADI-2 FS work with the HDSP (technically) in this way as a monitor out?
If so, i will get one next month, and get this ship underway.
Thanks again,
~Ht

Just for your information: I don't want to persuade you to get another card if you don't want to.

Latency wise, all RME products have a low latency, only little differences.
See my blog article which shows RTL as reported by the RME driver.

https://www.tonstudio-forum.de/blog/ent … cts-en-de/

AFAIK, you can trust the values that RME compiled in into the driver, at least this is the outcome whenever this topic shows up. Therefore it is valid to use those reported values in such a comparison, at least for RME products. What other vendors do is sometimes their "magic"

ok.
Btw the name of my forum nick is ramses, DAW mastermind is one of rankings usual in forum software.
But if you prefer, I can call you "New member" from now on

Did you get anywhere with this? I have a similar problem. So long as I only connect headphones they're absolutely silent, but as soon as I connect the main outputs I get digital noise in the headphone output - even if I only connect the speaker cables, and don't actually turn the speakers on. I know absolutely nothing about electronics, but it strikes me that this can't be a grounding issue, or dirty power supply, or I'd get the noise all the time.

As far as I can tell there is no noise on the main analogue outputs, whether or not I have the headphones plugged in, and no noise on the analogue inputs. So I'm also considering using the ADAT outputs to provide a headphones connection, but I have no way of testing whether the digital outputs are also affected by noise, and I don't want to go ahead and buy a convertor without knowing. Did you get as far as that?

D'oh - you're quite right. UK plugs are absolutely always grounded, whether power is on or not. Tried literally unplugging the speakers, and the headphones went silent.

I'm still not sure why - because my PC tower and the speakers are plugged into the same extension cable, so their route to ground is the same path, but it seems to matter anyway. That's good news, since the mains plugs to the speakers are quite accessible, so I can simply unplug them when working with headphones. It doesn't bode well for recording though - haven't got a phantom power unit yet, but presumably that will also give the card a second ground.