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XLR or RCA?

Dear audiogon community,

It was recommended, in another post, that I try a difference IC cable. I was considering the audio quest columbia XLR. ( I am currently using xlr cable between by c2300 preamp and mc275 amp). However, I then read that xlr cables only provide a real benefit if you are using balanced cables throughout your entire system, which I presume means from my turntable into my preamp. Is this true? Because if it is, perhaps I should switch to RCA. That is, my tonearm cable ends with RCS cables. In fact, my pre-amp does not have xlr inputs for phono (though it has them for everything else).

I plead with you, the wise audition community, to lead me out of this mystery!
elegal
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jburidan
803 posts
 
My Cary SLP 05 sounds better with RCA, so that's what I use.
rsimms
150 posts
 
I have a Calypso tube preamp. It has fully balanced differential inputs and outputs. When I use the differential inputs and outputs I loose much of the tube character of my preamp. I have a tube preamp to get the euphonic tube sound to music. Tubes improve the emotional impact and add a wonderful organic character to the music. The differential inputs and outputs seem to be clearer and possibly more technically accurate versus the single ended ones. I guess that is due to the noise and distortion canceling effect of true differential circuitry. I use the single ended inputs for music and use the differential inputs for HT. I gather this only applies with true differential circuits and probably won’t apply to Macintosh. If so, then I would think the XLR connections would be best whenever they are available. Of course, the only true answer is your own ears. This is just a guide to know what kind of things to listen for.

Bob
effischer
560 posts
 
I just changed out some antique 25 foot RCAs running from my C50 to my MC302 with 5 meter XLRs and dropped the noise floor substantially. Immediately noticeable. Can't give you a critique of the sound quality yet as I haven't been able to do any serious listening, but so far I'd say I made the right move. Even though you are all tube, I strongly suspect you will find the same thing. Dropping the noise floor always allows more fully resolved fine detail.
kijanki's avatar
kijanki
4,428 posts
 
Bob, differential amplifier can suppress even order harmonics (associated with warm sound). Voltage of each output can be seen as:

Vp=a1*Vi+a2*(Vi^2)+a3*(Vi^3)+a4*(Vi^4)+a5*(Vi^5)+ .....

Vn=a1*(-Vi)+a2*(-Vi^2)+a3*(-Vi^3)+a4*(-Vi^4)+a5*(-Vi^5)+ ....

where "a2, a4 etc" are even order coefficients. Since polarity of the input signal will be always positive (always raised to even power) for even order harmonics they appear same on each output and will be removed (assuming identical gains).

Vp-Vn=2a1*Vi+2a3*Vi^3+2a5*Vi^5....

The other problem might appear when gains are not exactly even because it can convert common mode noise/interference into normal mode signal.
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