Re: Cambridge Audio - an open letter [long]

Stewart Pinkerton wrote: 
On Fri, 28 Oct 2005 08:05:30 +0000 (UTC), Rob
<removethispatchoulian@xxxxxxxxx> wrote:


Stewart Pinkerton wrote:

On Thu, 27 Oct 2005 22:25:50 +0100, Dave Giles <spam@xxxxxxxx> wrote:


Stewart Pinkerton wrote:


Given that you can buy 24/96 sound cards for your PC which demonstrate
more than 100dB dynamic range,  that wouldn't seem to be much of an
issue for 16/44 CD.


Maybe those sound cards are pretty well shielded - I don't know. I know that
the Linn Tunboks uses a conventional PCI sound card (albeit a Linn
soundcard, as conventional as that makes it), so I appreciate that a PC
which doesn't interfere with it's analogue output isn't impossible.
However, my point is that there have been no assurances from Cambridge
Audio that this is the case.


Can't recall 'assurances' from any manufacturer that their DAC is
shielded - it's just basic engineering.


Look up the Yamaha 1300 HD recorder - that's an example. Also you'll find meridian (amongst others) use external DACs for ultimate shielding. 


Regarding your comment about Meridian, it is about as far from the
truth as you could get. Meridian, like most 'high end' manufacturers,
offer a standalone DAC for those with multiple digital sources, or
(more genuinely) for those who buy the bull*** about separates being
superior, thereby allowing them to sell two very expensive boxes - one
of which contains about fifty quids worth of working parts. Look at
the inside of any Meridian one-box player and you'll see immaculate
shielding plus the use of multilayer PCBs with ground planes. Indeed,
the earlier Meridian players were notable for the fact that they were
really two boxes in one outer casing.


OK, thanks for that.


The Cambridge has a CD writer - differences in performance and engineering are well documented. Whether they're audible differences or not I couldn't say for certain. 


Please specify what differences you *claim* exist between the output
datastreams of writer and player transports when replaying CDs at 1x
speed.


Firstly, *I* make no claims about audio performance. Secondly, my point was that the 640H uses a CDRW, not a CDR. Thirdly, 1X playing speed is just one factor in this machine - it extracts data (when compressing to MP3) at far higher rates for example. And in this regard DAE, and errors produced, varies between drives. In fact this is an example where I would claim audio performance differs between drives, based on personal experience. Fourthly, physical noise varies between drives. Whether these are audible (in the sense of what comes out the speakers) differences or not I couldn't say - I simply don't know - with the exception of point three.


So what we've got is a CD-RW drive which spins right

up to 52x - or whatever - making it useless as a regular CD player as it'd
be too noisy, and certainly not comparable with the 640C as a straight CD
player.


You have absolutely *zero* reason for such a claim, since you haven't
actually seen the thing in operation - and nor has anyone else, of
course.


These devices are, in general, noticeably noisy when copying anything other than in real time. 


So what? When *playing* a CD, it will be running in real time.


And when playing a mp3? (I actually don't know - never thought about it!)


Granted, these are criticisms of a product which is yet to be released; the
point of this post was to raise issues (both actual and potential) with the
640H (and to make a point about their removal of their forums).


You have yet to show that there *are* any real issues.


Concenrs are based on plain commonsense. 


No, they're based on ignorance of basic engineering.


I think at least some of the concerns are directed at the engineering - the drive (if only you can accept that drive noise is an issue for some) and use of a fan.


I accept that you have no experience of machines of this kind. However, I'm sure you could raise certain concerns related to say your gramaphone, needle or wireless just by looking at it and knowing the marketing specification. The point of this product is that people who know about such machines have raised points of *possible* concern - they just haven't been answered. 


I've been involved with considerably more sensitive and
high-performning machines in a *design* capacity for more than thirty
years, indeed I designed several ADCs and DACs back in the '70s.


Ah, OK. You clearly know something about something, although perhaps you can accept that some of the concerns (not the shielding though) of the OP are valid, and not answering those concerns is shoddy producer behaviour.

Rob

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