"S888Wheel" wrote in message
...
snip
My hi-fi sounds great sometimes and not others.
snip
Maybe you could give us the specifics on your system.

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

Chord Optichord digital link,
Audioquest Python interconnects,
Atlas 2.0 speaker cable,
Atacama Equinox rack

The dealer advised a 30 to 60 minute warmup before each listening session - which is a
pain and I'm not convinced that the improved sound quality follows such a warmup. The
improvement seems random - and unexpected. Maybe mains problems? The sonic difference to
the bass is quite clear. Forgive the adjectives but when it's not working well the sound
is OK but 'thin' and lacks energy. When it works well the bass is rich and the sound
fuller and more musical at the same volume. It even sounds good with the volume lower.

The Audioquest Pythons were the last addition. I wasn't happy with the system - it didn't
have the clarity - until they were added to replace Atlas Voyagers. Does the kit list
above give any clues as to why the sound would change? (BTW, thanks too for your
suggestions on test CDs.)

On Thu, 15 Apr 2004 14:03:06 -0400, "Arny Krueger"
wrote:

That is usually the case. The early stages of the main part of the
power amp circuit often run off the same source as the output
devices. In other cases there is some built-in extra filtering.

http://www.citycom.gr/electronics/pr...l/100ampl5.gif
shows a fairly typical design. Everthing runs off the same voltage
source as the output devices.

If by 'extra filtering' you're talking about C9 and 1, then it's not
really very useful-

I'm not talking about that at all. Sorry for any possible lack of clarity. I
intended this to be an example of a power amp where everything runs off the
same basic voltage source as the output devices.

No, I don't understand. You said 'In other cases there is some
built-in extra filtering,' and you provided a link to an amp that has
local smoothing provided by capacitors 8 and 1. Now you say you
weren't 'talking about that at all'.

As a rule, tweaks such as this just don't have any practical technical
advantages.

And of course we all know that pretty much every nominally competent
amp (in terms of measurement) sounds just like any other of same . . .

--
td

The Devil wrote:
On Thu, 15 Apr 2004 14:03:06 -0400, "Arny Krueger"
wrote:

That is usually the case. The early stages of the main part of the
power amp circuit often run off the same source as the output
devices. In other cases there is some built-in extra filtering.

http://www.citycom.gr/electronics/pr...l/100ampl5.gif
shows a fairly typical design. Everything runs off the same voltage
source as the output devices.

If by 'extra filtering' you're talking about C9 and 1, then it's not
really very useful-

I'm not talking about that at all. Sorry for any possible lack of
clarity. I intended this to be an example of a power amp where
everything runs off the same basic voltage source as the output
devices.

No, I don't understand.

What's unclear about the explanation I just gave you?

You said 'In other cases there is some
built-in extra filtering,' and you provided a link to an amp that has
local smoothing provided by capacitors 8 and 1. Now you say you
weren't 'talking about that at all'.

There is he slight matter of the sentence:

"Everything runs off the same voltage source as the output devices."

Same paragraph as the link.


As a rule, tweaks such as this just don't have any practical
technical advantages.

And of course we all know that pretty much every nominally competent
amp (in terms of measurement) sounds just like any other of same . . .

You know that, eh? I perceive a change of philosophy on your part. When did
this happen?

On Thu, 15 Apr 2004 17:36:25 -0400, "Arny Krueger"
wrote:

That is usually the case. The early stages of the main part of the
power amp circuit often run off the same source as the output
devices. In other cases there is some built-in extra filtering.

http://www.citycom.gr/electronics/pr...l/100ampl5.gif
shows a fairly typical design. Everything runs off the same voltage
source as the output devices.

If by 'extra filtering' you're talking about C9 and 1, then it's not
really very useful-

I'm not talking about that at all. Sorry for any possible lack of
clarity. I intended this to be an example of a power amp where
everything runs off the same basic voltage source as the output
devices.

No, I don't understand.

What's unclear about the explanation I just gave you?

See below.

You said 'In other cases there is some
built-in extra filtering,' and you provided a link to an amp that has
local smoothing provided by capacitors 8 and 1. Now you say you
weren't 'talking about that at all'.

There is he slight matter of the sentence:

"Everything runs off the same voltage source as the output devices."

Same paragraph as the link.

Yes. But you specifically mentioned 'extra filtering' for the small
signal stages ('early', in your technical parlance) of an amp, then
posted a link to an amp which does not posses that filtering.

As a rule, tweaks such as this just don't have any practical
technical advantages.

And of course we all know that pretty much every nominally competent
amp (in terms of measurement) sounds just like any other of same . . .

You know that, eh? I perceive a change of philosophy on your part. When did
this happen?

It didn't. I know it's bull****.

--
td

James Harris wrote:
"S888Wheel" wrote in message
...
snip

My hi-fi sounds great sometimes and not others.

snip

Maybe you could give us the specifics on your system.


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?)

On Thu, 15 Apr 2004 22:58:23 +0100, The Devil wrote:

On Thu, 15 Apr 2004 17:36:25 -0400, "Arny Krueger"
wrote:

And of course we all know that pretty much every nominally competent
amp (in terms of measurement) sounds just like any other of same . . .

You know that, eh? I perceive a change of philosophy on your part. When did
this happen?

It didn't. I know it's bull****.

Oh, really? I'm still up for it if you are, with your trusty
Quads...........

--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 16 Apr 2004 06:57:21 +0000 (UTC), Stewart Pinkerton
wrote:

Oh, really? I'm still up for it if you are, with your trusty
Quads...........

Actually, I think the 989s are less sensitive to power amps than most
other speakers. ATM, I'm driving them with a cheapy Rotel (PSU Black
Gated--more snake oil :-)) and they sound very . . . Quadish.

You've already found differences among power amps that measure well.
No need to re-prove what you already know, Stewart. :-)

--
td

In article , James Harris
no.email.please wrote:
"S888Wheel" wrote in message
... snip
My hi-fi sounds great sometimes and not others.
snip
Maybe you could give us the specifics on your system.

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

Chord Optichord digital link, Audioquest Python interconnects, Atlas 2.0
speaker cable, Atacama Equinox rack

Since this is being cross-posted to 'opinion'... :-)

FWIW I use two main systems. One now uses a pair of ESL63's and a Meridian
263 DAC. The other now uses a pair of ESL988's and a Meridian 563 DAC. (You
may spot a pattern, here... ;- )

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. However the
changes are so small I am not at all sure of this. I general I don't bother
switching on amplifiers more than a few mins before use. So far as I can
tell, letting my amplifiers warm up has no effect that seems audible to me.


The dealer advised a 30 to 60 minute warmup before each listening
session - which is a pain and I'm not convinced that the improved sound
quality follows such a warmup. The improvement seems random - and
unexpected. Maybe mains problems? The sonic difference to the bass is
quite clear. Forgive the adjectives but when it's not working well the
sound is OK but 'thin' and lacks energy. When it works well the bass is
rich and the sound fuller and more musical at the same volume. It even
sounds good with the volume lower.

The Audioquest Pythons were the last addition. I wasn't happy with the
system - it didn't have the clarity - until they were added to replace
Atlas Voyagers. Does the kit list above give any clues as to why the
sound would change? (BTW, thanks too for your suggestions on test CDs.)

I also hear (apparent) changes from time to time in terms of relative bass
level, etc. However it does not seem to correlate with anything so I
suspect it is just my perceptions altering as a result of various
'extraneous' influences...

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

In article ,
Tat Chan wrote:
James Harris wrote:

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?)

I doubt that this is simply a matter of choice of DAC chip. Other
influences will include the PSU, buffering, differences in filtering, etc.

FWIW I remain a fan of the Meridian 263 and 563, (as well as the Quad 67)
despite them being 'out of favour' for a while for technical reasons.

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

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

In article , Mike Gilmour
wrote:



Replacing rectifiers with Schottky barrier ones that supposedly don't
generate reverse recovery transients from stored charge & minority
carrier injection - does that change the situation much even if you
don't use a regulator chip?

When designing/building amps myself I just used to shove small caps in
parallel with each bridge diode to eat the 'snap'...

However for me the main line of defence was a design that inherently had a
good amount of rail ripple/noise/interference rejection, and good earthing.
This means that even of HF rubbish gets through the PSU them amp will
largely ignore it.

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