Polarity with Meridian 500 transport and Arcam BB2

Hi.

Sorry to ask a question with my first first.

I have purchased a s/h Meridian 500 transport. I have connected it to my Arcam Black Box 2 (modified by Chevron Audio) and in order to work it required the "polarity switch" at the rear of the BB2 to be switched in which is contracy to the other Spdif sources I have connected to the BB2 (Chevron fitted a source switch, USB input, for me etc). The switch is in the middle of the back plate and almost imposible to get to on a regular basis.

I have searched the internet but I can't a clear discription of what the "polarity switch" does. It is not a phase inversion (in the anaolog domain) as a phase switch is also fitted at the front of the BB2. I have also looked inside the Meridian and apart from determinging that the SPDIF is supplied via a PCF2705 chip (which appears to have a copper plate on it) and then further Meridian stuff before the coax out I am struggling.

The alternative is to us ethe potical out but I am inclined to this being worse than the coax out; the coax goes into a Theta TLC and then the BB2.

I would very much like to either move the switch (assuming it does not degrade the sound) or, better still, mod the Meridian. the Meridian has an Audiocom clock and beat my Roksan Kandy as a transport so it is a keeper.

I would appreciate any comments.

Many Thanks.
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Not sure on this as I understood SPDIF is phase insensitive. The only thing I can think of is that it either alters the sensitivity (dim recollection of a 5 volt pk pk output as against the normal -/+1 volt unterminated in some equipment). The word phase is very specific though.

Could the Meridian use some non standard output in some way... not above/below ground output as is normal. Unbalanced in other words. If so you might be able to mod the Meridian.

In fact I'm just searching for that now and find,
Anybody know why Meridian chose SPDIF (unbalanced) over AES/EBU (balanced)? - The Hitchhikers Guide To Meridian

using balanced digital input with unbalanced source

so I think that's it...