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. 
dbphd
I'd opt for balanced myself. Ralph at Atma-Sphere says balanced cables don't influence sound like unbalanced, and are less affected by distance.
Bob
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Ralph's (Atmasphere) comments regarding a differential balanced circuit eliminating cable artifacts is based on the balanced design supporting the 600 ohm standard, as Atmasphere designs do. It is my understanding that not all balanced designs support this standard.
Clio,

That is correct that some balanced designs don't support the 600 ohm standard.

dbphd,

i presently use balanced cables in my system because I have 2 meter cables from my dac to my pre and also from my pre to pwr amps.I have noticed a quieter noise floor vs rca cables in my system.You may need to try some balanced cables in your system and see.There is really not a right or wrong way to this subject it just depends on what works the best for you.If you are using rca cables longer than 2 meter or so you probably would want to use balanced if possible.

Kenny.
Ayre gear is optimized for balanced connections and always sounds best when run fully balanced. If the Oppo is truly balanced (dual differential), then you'll get the best results that way. 
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Bob,
The surgery was successful, and I have not experienced any pain since.  The worst part was the 3-week taper off the opiates.

ciamara,
The Oppo 205 is claimed to be fully, i.e., dual differential, balanced.  I may use a passive switch for sharing a balanced input between the Sony HAP and the 205 until I get a KX-5 Twenty that has additional balanced inputs.

db
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Good link to the Benchmark objective test. I suggest to try yourself with an inexpensive star-quad cable, or even to go to audiosensibility.com for a star-quad cable made with Ohno contiuous cast copper and Teflon insulation at a reasonable cost.
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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^^ Right!
And, it is so nice not to have to worry about buying expensive balanced interconnects.
Bob
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
600 ohms is still the standard in recording studios, at least according to Tim de Paravicini, designer of the EAR-Yoshino electronics and many pro studio installations (including Pink Floyd's London one).
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600 ohms is still used, on account of the fact that there is still a lot of vintage professional gear in service, in fact many studios like to advertise that they have such (tube) equipment. So usually modern gear is designed to support that operation in the studio. We built that capacity into our balanced preamps as well.
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