[JASLJS]

I just got a Bryston BP25 but my SACD player has unbalanced outputs(RCA), which would be better unbalanced from the SACD player or is there any benefit using cables that is Balanced at one end and unbalanced at the other end ?

[Elizabeth]

Use the single ended RCA interconnect. 
Using a RCA to XLR  is a compromise connection best left to dire need.
The one possible plus of a RCA to XLR might be if the CD player was overloading the preamp. (not likely)

[Speedskater]

Going "RCA output>>adapter>>XLR cable>>XLR input" is good.
But sometimes there are volume differences.
Going XLR to RCA can be tricky.

[James Tanner]

Hi

With Balanced lines you must have a a balanced sending circuit and a balanced receiving circuit to have a balanced connection (as well as a properly configured balanced cable).  So both the source and the receiving component must have a fully differential balanced connection to have the benefits balanced lines offer.

james

[mmalkie]

So basically, there is NO advantage (or disadvantage) using for example a RCA to XLR connection as there is no balanced output from the RCA end?

[brucek]

So basically, there is NO advantage (or disadvantage) using for example a RCA to XLR connection as there is no balanced output from the RCA end?

Well, there's some advantage and some disadvantage. The RCA to balanced input is a pseudo-balanced situation where the CMR (common mode rejection) ratio is seriously compromised compared to a proper balanced interface and ofttimes you won't have sufficient audio levels as both the (+)ve and (-)ve signals are expected to contain the signal with an associated maximum line level. One of your inputs will be at ground potential. 

Conventionally the two signals are fed into a differential amplifier at the receiving end and the CMR advantage is fully realized since the two signal carrying conductors have identical impedances to ground (as in a proper balanced circuit). This will give the maximum noise rejection. Your grounded input will degrade the CMR since there is an impedance imbalance.

Yes, you'll still realize a small CMR advantage compared to an unbalanced to unbalanced RCA connection, but it's quickly lost in practice. The level out of the differential amplifier is at a 6dB (half the voltage) disadvantage to a proper symmetrical signal. So to obtain the same level you must increase the level from the source with resulting raised noise floor. Your advantage is lost.

Using RCA to RCA would be best.

[mmalkie]

Thank you...........that was a very technical response and I appreciate the explanation. I will keep my RCA to RCA attachment.