On Sat, 31 Jul 2010 09:18:11 +0100, "David Looser"
wrote:



I hadn't heard that; FWIW the Sony 'PCM-on-Betamax-cassettes' system was
14-bit.

It was 16 bit switchable to 14 bit. (I've still got a PCMF1.)

Philips started the development of CD as a 14 bit system with a
smaller disc than they ended up using. At some later stage they
started cooperating with Sony. It was Sony who wanted the higher bit
depth and they also wanted the playing time increased, so the disc
diameter increased. The story is that Akio Morita wanted to be able to
play Beethovens 9th without interuption.

At the time Sony had been developing digital audio systems for some
time and had the capability to make 16 bit converters. Philips could
only manufacture 14 bit converters, and the oversampling that they
ended up using was a way in which they could keep up with a 16 bit
spec, but using the 14 bit converters that they had.

At the time (late 70s) this was difficult technology to mass produce
and Philips original 14 bit system was much potentially much better
than LP anyway. Sony improved it and future proofed it well.

Bill

"Bill Taylor" wrote in message
...
On Sat, 31 Jul 2010 09:18:11 +0100, "David Looser"
wrote:



I hadn't heard that; FWIW the Sony 'PCM-on-Betamax-cassettes' system was
14-bit.

It was 16 bit switchable to 14 bit. (I've still got a PCMF1.)

Yes, but the older PCM100 unit used with mains Betamax VCRs was only 14 bit.
Presumably the 14-bit switchable facility on the PCMF1 was to provide
compatablity with them.

At the time Sony had been developing digital audio systems for some
time and had the capability to make 16 bit converters.

I'm not convinced that anybody at the time had the capability to make
monolithic converters that actually delivered 16-bit performance. Certainly
none of the ones I measured at the time (inc. Burr-Brown which were supposed
to be the best) did so. If you wanted true 16-bit performance you needed to
go to hybrid DACs which were too expensive for consumer use.

David.