help with absolute phase


ive just upgraded my Bryston .5b to a YBA2.I understand that this preamp inverts absolute phase.How can i tell if the phase is correct or correct it if its not.i also was wondering if most higher level preamps do this....any advise would help greatly. thanks in advance.
antmo
would anyone know where a test disc can be purchased,none of the local dealers have them.
and thanks for all the great info!
onhwy61 makes several good points, that also address the query of chelillingworth directed to me. generally, you will be able to detect whether your system is in relative phase by checking the "channel phasing" of your speakers. this can be accomplished with stereophile test disc 2. if your channels are out of phase, then you've got some wire(s) crossed somewhere that affects both the relative and absolute phase. "sytstem phase" is testable with the stereophile test disc 1. i cannot attest to its accuracy, tho, i am usually able to detect by listening when a system is connected out-of-phase. absolute phase correctness requires more than a test disc or my ears can offer and i don't really worry about it, as, again, onhwy61 suggests.
am0779@aol.com: you can buy the stereophile test discs online at: http://www.stereophile.com/
goto: "recordings."

the ortofon (i misspelled it in my earlier post) test lp is long out of print but can be found, if you're in luck, at places where used lp's are available. good hunting. -kelly
Onhwy61's post was excellent. My recommendation that you make the change was no more than regurgitating audiophile best practices. But truth to tell, I don't hear a meaningful difference myself. I have known some who are highly sensitive to it, however.
There might be a whole other problem that goes along with preamps that invert phase: Does it mean that your cable to the amp is sending the negative signal through the positive conductor and visa-versa?!! Think about it... most cables are designed to handle both these polarities in very different ways and if the preamp inverts them, you have just tossed out all the cable's design .I have only seen one cable that is offered specially configured for inverted phase signals, and that was the Mapleshade.