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Balanced v unbalanced input to Ayre preamps

I've been using unbalanced connection between an Oppo 205 and Ayre K-5xeMP preamp, but wonder if the sound with balanced might be superior.  According to Oppo Tech the sound with the balanced or unbalanced outputs from the 205 should be identical, presumably at reasonable cable lengths.  But is the same true with Ayre preamp inputs?  

I'm hoping to replace the K-5 with a KX-5 Twenty to match my VX-5 Twenty amp; the KX-5 has more balanced inputs.  An Ayre C-5xeMP and Sony HAP-1ES use the two balanced inputs of the K-5. 
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atmasphere's avatar
atmasphere
11,844 posts
 
Can someone explain why handling a 600 ohm load is a critical factor for making cables used in balanced lines sonically a non-issue? It's not related to CMRR then, right?
These days 600 ohms is no longer the standard (although since transformers are still often used, its still around) although there is the expectation that the connection will have a low impedance input of 2000 ohms or less.

The reason for this is that if any noise is induced in the cable, it is usually a weak source (like a magnetic field) compared to the actual signal. So it does not have the same ability to drive the input load like the signal does. Its a simple means of 'swamping' noise out and has the added benefit of reducing the effect of capacitance in the cables.
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atmasphere's avatar
atmasphere
11,844 posts
 
^^ Right!
gdnrbob
4,449 posts
 
And, it is so nice not to have to worry about buying expensive balanced interconnects.
Bob
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dbphd OP
1,630 posts
 
IIRC, when I was a grad student working in a psychoacoustics lab during the 60s, 600Ω was the standard.  And then came the DEC PDP-11 lab computer.

db
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