All what Anthony said is correct.
Input impedance of the Orelo is IIRC around 80K Ohm.
Fine to wire up the new 1x stereo NOS1 XLR sockets in same fashion?
Pete, this depends on what you actually are going to do with it. You
suggest to try another fine (XLR) cable. But if this is really so - and nothing else, then this obviously won't work because your Orelo does not have balanced inputs.
If this is, however, about a 2nd NOS1 you possess and this is to be connected to something very else with balanced inputs, then fine in itself. But I am not so sure about this, and thus :
The answer is No. In whatever event you can't hope for anything good with a cable made for balanced purpose (your XLR) to behave in any good fashion if it is used as an RCA cable with a wrong impedance on top of it (not that RCA bears a formal impedance but alas).
I see another combination : you do have that 2nd NOS1 and want to try this with your fine XLR on your Orelos ...
... forget it.
In that case you can leave the old BNC connection be - which you BTW can do anyway, but it will be a total mess electrically. Not that things will explode (all voltages will remain fine) but it will sound like a drag; The half of the XLR you will be using will be worse than a pair of shoe lashes as nothing in that cable will be made / be shielded etc. etc. for single ended operation.
The upside of this all will be that - also with your own original NOS1 you could do this,
besides your BNC connection (this is what you asked about too). Thus, no harm done to anything for the BNC connection. But ...
Now this puzzle is pieced together somewhat for me, you won't even had the additionally required wires for a
proper XLR connection (they are not hanging loose somewhere in there).
Lastly, electrically such a "faulty" connection has never been tried by me, and again I say the same : it will sound like a drag.
Side note (or not) : I recall a most simple desired combination of two pairs of outputs chosen from RCA, BNC and XLR (but I forgot which), and there was no way I could make that sounding right. The customer in order received an "impossible" from me. But that was judged with
my ears and such. What you seem to head for is similar. Thus, what I am saying here is that because of your "illegal" XLR connection, your BNC will sound wrong too. "Will" ? I can't guarantee it.
Do notice please, that all what is impedance "draws" on the output. In this case this is quite directly D/A converter chips (with only one tiny resistor in the path) which have a relation among hem as well (2x 2 for one channel). Thus, draw on this wrongly (or untested) and the one will tear down the other (read : your half-XLR will draw on the other BNC, whether XLR is used or not (not used : means : open ended AKA not terminated). This is fine when it sounds fine. And if you really paid attention, you noticed that this drawing could be on the same chip- half, or the other (of one channel). With Single Ended one half is used for both outputs (like BNC + RCA). With XLR, both halves are used. With half-XLR maybe the other half should be used. LOL.
Try it and let us know ?
And have fun of course !
Peter
