System warm-up
 

In article , Chris Isbell
wrote:
On Fri, 16 Apr 2004 11:43:39 +0100, Jim Lesurf
wrote:

In each case I tend to switch the speaker energisation and DAC power on
in the morning, and off at the end of the evening. I have a slight
impression that the speakers (and maybe the DACs) benefit from this.

The manual for the Quad '57 speakers recommends leaving them powered all
the time and not switching them off. Is the advice given for the
'63/988/989 different?

I don't have the 63 booklet to hand. My recollection is that it also
recommends leaving the mains 'on' all the time.

Looking at the blue one for the 988's I can't find a mention of this,
though.

Ideally, I'd leave them powered all the time. However I tend to be wary of
leaving items on overnight due to the very slight risk of fire.

My Stax electrostatic headphones sound noticeably 'edgy' for the first
few minutes after switch-on. I have not investigated this in any detail,
but it seems reasonable that high-impedance capacitive systems will need
a little time to stabilise because there may be some fairly long time
constants associated with the biasing supply.

My impression is that the speakers do improve over a few hours of being
'on'. However this may be my ears, of course, not the speakers. :-)

On one occasion I was away for a week and left the 63's unpowered. I cam
home and started listening to music. It was only after about ten minutes
that I realised that I'd set the volume about 6dB higher than usual, and
that the sound was 'not quite right'. I hadn't turned on the energisation.
:-)

This shows that they do sometimes keep a surprisingly high charge for a
long time.

IIRC the 57's would not hold charge like this, though.

I'm not sure, but suspect the problem may be that the charge distribution
(rather than amount) needs to 'settle' and this takes times as the
diaphragm is actually quite resistive. Also any moisture may need to be
'ionised away' by leakage. This might be a reason for allowing the speakers
to be powered for a long time.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

System warm-up
 

In article , Chris Isbell
writes
On Fri, 16 Apr 2004 11:43:39 +0100, Jim Lesurf
wrote:

In each case I tend to switch the speaker energisation and DAC power on in
the morning, and off at the end of the evening. I have a slight impression
that the speakers (and maybe the DACs) benefit from this.

The manual for the Quad '57 speakers recommends leaving them powered
all the time and not switching them off. Is the advice given for the
'63/988/989 different?

Leave mine on all the time, doesn't seem to harm them. Better than not
remembering to switch them on as other members of the tribe here use
them and would forget!....

--
Tony Sayer

System warm-up
 

In article ,
Jim Lesurf wrote:
I'm not sure, but suspect the problem may be that the charge
distribution (rather than amount) needs to 'settle' and this takes times
as the diaphragm is actually quite resistive. Also any moisture may need
to be 'ionised away' by leakage. This might be a reason for allowing the
speakers to be powered for a long time.

I'd agree with the moisture thing - it's the same with condenser mics. But
because one particular type of speaker benefits from being left on (or
warmed up), it doesn't mean other things necessarily will.

--
*He's not dead - he's electroencephalographically challenged

Dave Plowman London SW 12
RIP Acorn

System warm-up
 

On Sun, 18 Apr 2004 12:22:19 +0100, Jim Lesurf
wrote:

On one occasion I was away for a week and left the 63's unpowered. I cam
home and started listening to music. It was only after about ten minutes
that I realised that I'd set the volume about 6dB higher than usual, and
that the sound was 'not quite right'. I hadn't turned on the energisation.
:-)

This shows that they do sometimes keep a surprisingly high charge for a
long time.

IIRC the 57's would not hold charge like this, though.


My experience is that they hold up for about ten minutes. (This is
based on the occasion when my better half unplugged one of them to do
some ironing. The reeducation programme appears to have been effective
and she has not repeated the offence. ;-)


--
Chris Isbell
Southampton
UK

System warm-up
 

Jim Lesurf wrote:

snip

thanks for all the info.


what would the technical reasons be? Did they process/filter the digital
data in a "funny" way?


They use low-bit sigma-delta. Hence they tend to produce the same sort of
ultrasonic 'hash' as SACD. Can also, theoretically, suffer from some of the
same drawbacks as other low-bit methods. However in the end this comes down
to how good a job the engineers did.



would the ultrasonic hash lead to a "pleasing" kind of distortion? On a
thread a few weeks back, it was pointed out the my Rotel 965BX CD player
was noisy, with a lot of ultrasonic noise. And, the Rotel was one of the
early bitstream CD players as well (I am under the impression that SACD
uses a conversion method similar to bitstream conversion from the early 90s)

And could the ultrasonic noise explain why some people have been
comparing SACD to vinyl?

Maybe they'll become popular again if SACD really takes hold. A
situation with a certain wry irony for Bob Stuart if it occurs... ;-


and why would that be? (possibly related to my question above)


Because Bob is what might be termed a 'critic' of the SACD system and he
would prefer LPCM as used in DVD-A to avoid the potential problems of SACD.

and he's responsible for the MLP (Meridian Lossless Packing) format used
in DVD-A!

System warm-up
 

In article , Tat Chan
wrote:
Jim Lesurf wrote:

snip

thanks for all the info.


what would the technical reasons be? Did they process/filter the
digital data in a "funny" way?


They use low-bit sigma-delta. Hence they tend to produce the same sort
of ultrasonic 'hash' as SACD. Can also, theoretically, suffer from
some of the same drawbacks as other low-bit methods. However in the
end this comes down to how good a job the engineers did.



would the ultrasonic hash lead to a "pleasing" kind of distortion?

Short answer: "Pass" :-)

Longer answer: "I suppose it might do in some circumstances. Indeed, I
wrote an article that Hi Fi News published a few months ago that included
this speculation as a possibility springing from the nonlinear nature of
human hearing." :-)

On a thread a few weeks back, it was pointed out the my Rotel 965BX CD
player was noisy, with a lot of ultrasonic noise. And, the Rotel was one
of the early bitstream CD players as well (I am under the impression
that SACD uses a conversion method similar to bitstream conversion from
the early 90s)

And could the ultrasonic noise explain why some people have been
comparing SACD to vinyl?

Again, I refer you to my above-mentioned article. :-)

Since I am in "plug" mode... There will be a follow-on article in a few
months. Book your issue of HFN early to avoid dissapointment. ;-

FWIW once the next item appears in the magazine, I am hoping to put a
longer account of the background, etc, on one of my websites.


Because Bob is what might be termed a 'critic' of the SACD system and
he would prefer LPCM as used in DVD-A to avoid the potential problems
of SACD.

and he's responsible for the MLP (Meridian Lossless Packing) format used
in DVD-A!

Yes. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

System warm-up
 

"Tat Chan" wrote in message
...
snip

Nad C541i as transport,
Meridian 203 DAC,
Rotel RA-02 amp,
Dynaudio Audience 62 floorstand speakers



James, I am curious. The Meridian DAC is at least 12 years old. I would
have thought that the newer Burr Brown DACs in the NAD would measure
better and produce "better" sound than the older Philips DAC in the
Meridian (is it multibit or bitstream?)

Well, since you asked I tried going back to the direct link from the CD player to the amp.
I soon went back to the DAC. The reason? I wouldn't like to say the DAC is "better" but is
a sound I prefer.

The DAC gives greater bass weight and authority and also opens out the voices. They sound
more clear and distinct with the DAC than with the Nad CD player alone.

I would still like more reach in the bass, though. That may be to do with my speakers more
than the electronics.

--
Cheers,
James

System warm-up
 

Jim Lesurf wrote:

In article , Tat Chan
wrote:


would the ultrasonic hash lead to a "pleasing" kind of distortion?


Short answer: "Pass" :-)

Longer answer: "I suppose it might do in some circumstances. Indeed, I
wrote an article that Hi Fi News published a few months ago that included
this speculation as a possibility springing from the nonlinear nature of
human hearing." :-)


UK magazines take a few months to reach Oz. With any luck, the newsagent will
have that copy in stock.


Since I am in "plug" mode... There will be a follow-on article in a few
months. Book your issue of HFN early to avoid dissapointment. ;-

FWIW once the next item appears in the magazine, I am hoping to put a
longer account of the background, etc, on one of my websites.


looking forward to it.

System warm-up
 

James Harris wrote:

"Tat Chan" wrote in message
...
snip


James, I am curious. The Meridian DAC is at least 12 years old. I would
have thought that the newer Burr Brown DACs in the NAD would measure
better and produce "better" sound than the older Philips DAC in the
Meridian (is it multibit or bitstream?)


Well, since you asked I tried going back to the direct link from the CD player to the amp.
I soon went back to the DAC. The reason? I wouldn't like to say the DAC is "better" but is
a sound I prefer.

The DAC gives greater bass weight and authority and also opens out the voices. They sound
more clear and distinct with the DAC than with the Nad CD player alone.


Interesting. I was thinking of getting a 203 DAC, as the shop I bought my
speakers from have one for sale, but the £160 they are charging seems a bit steep.

I would still like more reach in the bass, though. That may be to do with my speakers more
than the electronics.

well, your floorstanders will produce more bass than my bookshelves!

System warm-up
 

"Tat Chan" wrote in message news:c636ei$79kno$1@ID-
snip

Interesting. I was thinking of getting a 203 DAC, as the shop I bought my
speakers from have one for sale, but the £160 they are charging seems a bit steep.

I paid £150 (IIRC) for the unit second hand but I did get a chance to try it out for a
couple of weeks before parting with my cash. Your local shop may let you try the unit for
a few days before deciding.