As good a guess as any I've heard. I had a  chat 10 years ago with one of
the guys who created the Roksan line of audio equipement, Touraj Moghaddam.
He is a mechanical engineer and his babies are his turntables. His company
also developed CD players, of course, and he had interesting things to say
about the challenges. He said a lot of the trouble was in the drive servos,
spindle/laser carrage/focus/pointing. They created complex dynamic draws on
the power supplies, which were hard to isolate completely from the other
supplies. What's more, the system wouldn't respond the same way twice to a
particular disc. He asked me if I ever noticed that sometimes a disc doesn't
sound quite the same way two times in a row. That took me aback, as I
figured it would be me at fault, not perfect sound forever.

-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Tom Fine
Sent: Monday, February 11, 2013 3:01 PM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Audibility of 44/16 ?

One story I'd love some science applied to that's related to this -- are
there _really_ any differences between BMG Music Club CDs and the original
issue CDs? I've read several things over the years stating that BMG Music
Club versions of Mercury CDs sounded "inferior." But the few BMG versions I
have are bit-perfect replicas of the originals, so the bits is the bits.
What else could be "wrong"? Did anyone ever do any tests to compare baked-in
jitter for both discs, assuming BMG even used a different glass master?

I'm also mystified by recent reviewer statements that the new box set CDs
sound "better" than the originals (they sound the same to my ears), but in
those cases, with all the pre-1998 catalog numbers, they are indeed using
parts made from different glass masters from the US originals. The reason
was, US production was done at Philips-DuPont in North Carolina and
everything else was done at Polygram in Hanover Germany. Today, everything
is done in Hanover, using the Hanover manufacturing parts. The other
difference I've suggested to reviewers is mechanical playback. The original
US CDs had shiny/slippery cores around the spindle hole. Modern CDs are
somewhat rough and also are lighter net weight (by an ounce or more,
according to my scale). So they might present fewer mechanical problems for
a player, at least that's my theory (ie they get gripped harder because of
the rough surface and spin easier because they weigh less).

-- Tom Fine