Add a DAC to a cheap CD player?
 

[original post missing from my server]

In article , Jim H

My point is, with digital better fidelity means better at recovering
data. If high-end dacs were good at this they would find it harder
to justify ridiculous CD transport prices.

How would you square this view with my earlier comment that, if a cheap CD
drive can deliver faultless computer data, then a cheap CD transport should
be able to do so as well? Do CD transports lack error correction that one
presumes is present in computer kit?


--
Wally
www.art-gallery.myby.co.uk
Latest work: The Langlois Bridge (after Van Gogh)

Add a DAC to a cheap CD player?
 

"tony sayer" wrote in message
...
In article , just me
writes
It's a comparative thing. The DAC on my DAB tuner (Sony STD777es)
sounds
inferior then when compared with the sound whilst connected through
the
DAC
of the Arcam Black Box 500. I would assume that lesser DAB tuners
would
also
benefit in this manner. Yes the bitrate of the transmission has a
large
bearing on the sound, but then so does the DAC. When I buy a new
Freeview
box with digital output next month I should benefit from the superior
bitrates seemingly available via this platform with some broadcasts.

Yes better, but NICAM and FM still sound better.....

Not really relevant though. No UK radio transmissions employ NICAM (do
they
elsewhere?) whilst the radio services offered via Freeview aren't
available
on FM.

NICAM is used to feed the main FM transmitters in the UK well BBC ones.

I should have been more specific, but I think it was clear I was refering to
domestic broadcast services and not network operations.

The extra radio channels on freeview are not available on FM as you
rightly point out. However freeview does use higher transmission rates
then T-DAB..

Which takes us back to my previous point, "When I buy a new Freeview
box with digital output next month I should benefit from the superior
bitrates seemingly available via this platform with some broadcasts"

Add a DAC to a cheap CD player?
 

"tony sayer" wrote in message
...
In article , just me
writes
It's a comparative thing. The DAC on my DAB tuner (Sony STD777es)
sounds
inferior then when compared with the sound whilst connected through
the
DAC
of the Arcam Black Box 500. I would assume that lesser DAB tuners
would
also
benefit in this manner. Yes the bitrate of the transmission has a
large
bearing on the sound, but then so does the DAC. When I buy a new
Freeview
box with digital output next month I should benefit from the superior
bitrates seemingly available via this platform with some broadcasts.

Yes better, but NICAM and FM still sound better.....

Not really relevant though. No UK radio transmissions employ NICAM (do
they
elsewhere?) whilst the radio services offered via Freeview aren't
available
on FM.

NICAM is used to feed the main FM transmitters in the UK well BBC ones.

I should have been more specific, but I think it was clear I was refering to
domestic broadcast services and not network operations.

The extra radio channels on freeview are not available on FM as you
rightly point out. However freeview does use higher transmission rates
then T-DAB..

Which takes us back to my previous point, "When I buy a new Freeview
box with digital output next month I should benefit from the superior
bitrates seemingly available via this platform with some broadcasts"

Add a DAC to a cheap CD player?
 

On Wed, 10 Dec 2003 09:36:54 +0000 (GMT)
Jim Lesurf wrote:

DACs like the Meridian ones apply control loops to read in the data,
and then play them out under the control of a 'smoothed' local clock.
This can reduce the effects of jitter provided the input isn't too
bad.

well, there comes a point where cumulative jitter is more or less the
same as either no jitter, or (effectively) a different than expected
clock speed (with resulting loss of bits if it goes on long enough).

a 'smoothed' clock would basically be a 'super long timebase PLL' (is
that what you were getting at there?)

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

Add a DAC to a cheap CD player?
 

On Wed, 10 Dec 2003 09:36:54 +0000 (GMT)
Jim Lesurf wrote:

DACs like the Meridian ones apply control loops to read in the data,
and then play them out under the control of a 'smoothed' local clock.
This can reduce the effects of jitter provided the input isn't too
bad.

well, there comes a point where cumulative jitter is more or less the
same as either no jitter, or (effectively) a different than expected
clock speed (with resulting loss of bits if it goes on long enough).

a 'smoothed' clock would basically be a 'super long timebase PLL' (is
that what you were getting at there?)

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

Add a DAC to a cheap CD player?
 

Wally wrote:

[original post missing from my server]

In article , Jim H

My point is, with digital better fidelity means better at recovering
data. If high-end dacs were good at this they would find it harder
to justify ridiculous CD transport prices.

How would you square this view with my earlier comment that, if a cheap CD
drive can deliver faultless computer data, then a cheap CD transport
should be able to do so as well? Do CD transports lack error correction
that one presumes is present in computer kit?


I think all decks are basicaly the same at recovering data, its the
conversion to analoguw where the differences lie.

Ian

Add a DAC to a cheap CD player?
 

Wally wrote:

[original post missing from my server]

In article , Jim H

My point is, with digital better fidelity means better at recovering
data. If high-end dacs were good at this they would find it harder
to justify ridiculous CD transport prices.

How would you square this view with my earlier comment that, if a cheap CD
drive can deliver faultless computer data, then a cheap CD transport
should be able to do so as well? Do CD transports lack error correction
that one presumes is present in computer kit?


I think all decks are basicaly the same at recovering data, its the
conversion to analoguw where the differences lie.

Ian

Add a DAC to a cheap CD player?
 

On Wed, 10 Dec 2003 17:56:14 +0000 (UTC)
(Stewart Pinkerton) wrote:

With the 'async' SPDIF you will hear every bit correctly (and thats
still dependant on the conversion method). with a reclocked output,
given the clock will NEVER be a perfect match for the SPDIF clock
anyway, you are garaunteed to either drop or stretch a whole bit at
some point. ick.

No, this is simply not true - although it depends on an adequate
buffer.

No, you ARE wrong.

there are two scenarios, and jitter really isnt an issue, becaue

Scenario 1:

Two clocks are a *perfect* frequency match. Unheard of unless they are physically synchronised, which isnt what we are discussing, so discard this scenario.

Scenario 2:
The two clocks are not a prefect match, the DAC clock is either slower or faster than the data sources clock.

in this case, if its faster, it will (periodically) drain all its buffering, no matter how much there is, and will end up stretching bits to fill the gap (or playing silence, whatever)

if its slower, it will, periodically end up with the buffer over-filling and bits will be lost.

jitter is simply noise above, and will average out to nothing. If it DIDNT cancel out, it'd effectvely be a frequency drift of the data sources clock, which is no longer called jitter (duh).

such a 'drift' would imply a loss of data

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

Add a DAC to a cheap CD player?
 

On Wed, 10 Dec 2003 17:56:14 +0000 (UTC)
(Stewart Pinkerton) wrote:

With the 'async' SPDIF you will hear every bit correctly (and thats
still dependant on the conversion method). with a reclocked output,
given the clock will NEVER be a perfect match for the SPDIF clock
anyway, you are garaunteed to either drop or stretch a whole bit at
some point. ick.

No, this is simply not true - although it depends on an adequate
buffer.

No, you ARE wrong.

there are two scenarios, and jitter really isnt an issue, becaue

Scenario 1:

Two clocks are a *perfect* frequency match. Unheard of unless they are physically synchronised, which isnt what we are discussing, so discard this scenario.

Scenario 2:
The two clocks are not a prefect match, the DAC clock is either slower or faster than the data sources clock.

in this case, if its faster, it will (periodically) drain all its buffering, no matter how much there is, and will end up stretching bits to fill the gap (or playing silence, whatever)

if its slower, it will, periodically end up with the buffer over-filling and bits will be lost.

jitter is simply noise above, and will average out to nothing. If it DIDNT cancel out, it'd effectvely be a frequency drift of the data sources clock, which is no longer called jitter (duh).

such a 'drift' would imply a loss of data

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

Add a DAC to a cheap CD player?
 

On Wed, 10 Dec 2003 18:33:51 GMT
"Wally" wrote:

The best value for money in jitter immune DAC's is reputed to be the
Benchmark DAC1 which uses a sample rate convertor in front of the DAC.
It is a little out of your price range at $850 (no UK distributor
either).

Aye, a tad pricey. :-)

And, IMHO, the wrong solution to the problem. Can we say 'aliasing' ?

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.