In article , JustMe
wrote:


Some amps' frequency responses can alter during warm up. Whether this is
a reflection of poor design or the designer's intent is another matter.

I'd be interested to know which models do this, and by how much, and at
what frequencies, this change occurs. Not something I have encountered so
far as I can recall.

One of my favourite amps sounds *very* different when first powered up,
compared with when it's hot, to the degree that a demonstration of it
when cold would not impress me whilst, when warm, I love it.

Again, I'd be interested to hear the details.

I have no trouble leaving it on, so this isn't a problem for me. While I
may be curious as to *why* this is the case, I don't really care that it
is so - I prefer it and that's all that's important.

Well, it does seem like a 'problem' to me as it implies that the
performance will drift about with room temperature, variations in the music
power changing the temperatures of devices, etc.

KH in a recent issue of Hi Fi News did do some measurements that showed
that the distortion levels in some amps vary as they warm up. However
others don't do this. My recollection is that this has been a 'known'
possibility for decades. (I certainly worked on it when developing over 20
years ago!) Hence such things should in general be removable by correct
design in my experience. If the set sounds 'better' when 'warmed up' then
I'd prefer the design to give the 'better' performance almost from the
instant of switch-on. Not to have to leave the set on for a long time
first. Partly as this would be a minor irritation. Partly as, to me, it
seems like a sign that the designers have not investigated and tackled the
problem.

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

Some amps' frequency responses can alter during warm up. Whether this is
a reflection of poor design or the designer's intent is another matter.

I'd be interested to know which models do this, and by how much, and at
what frequencies, this change occurs. Not something I have encountered so
far as I can recall.

It's an Alchemist Kraken integrated -
http://www.alchemisthifi.info/ranges...pd6_integrated
_amplifier.htm. It's a class A amp so runs hot (I don't know how much the
fact that the room temperature is 20 or 25 degrees effects an amp that
"idles" at about 55 degrees). I have noticed the same changes on different
examples of the same amp though, in different environments and with
different speakers. Recently I found an old review of the amp which actually
stated that the amp's frequency response fluctuated for several hours before
settling down -
http://www.alchemisthifi.info/ranges...integrated-rev
iew-hifichoice.jpg - I presume that this result was gathered through
measurement.

One of my favourite amps sounds *very* different when first powered up,
compared with when it's hot, to the degree that a demonstration of it
when cold would not impress me whilst, when warm, I love it.

Again, I'd be interested to hear the details.

See above. Like I say, I don't mind the fact that this happens, nor the fact
that, on paper the amp is noisy or gives "distortion", as I like the amp
more than the modest inconvenience of permenant power-up.

I was at the hifi show in Manchester last week and overheard Eric Kingdom
from Sony talking about the digital Sony amps and talking about the sound
being "unusual" to some people because of the lack of distortion introduced
between source and speaker. He made the point that, what a lot of people
refer to as "musicality" was just colour and distortion introduced by amps.
I felt that this was probably right, but it didn't make me prefer the Sony
amp.

A lot of the talk from some posters in this NG seems to focus on the wrongs
of such distortion, that such deviances are down to poor design or the
delivery of an unnatural performance, that this doesn't reflect the truth of
the recording. To me this argument, although interesting, doesn't really
bother me. If I like the sound then I like the sound - I make no claim to be
pursuing any reality in my hifi as it isn't and connot be reality, my ears
don't work very well, my room's acoustics don't match the "real thing" etc.
Besides, live performance vary from venue to venue, the instruments used all
colour the sound in different ways and, in my experience, the selection of a
musical instrument will depend on a tonal preference - I certainly found
this when trying out pianos and would chose the one that I liked the sound
of most.

There's no doubt that the Kraken amp is coloured, but that colour is one of
the things that I like about it - I enjoy the music more and so it does what
I've paid for. Even the amp's designer says that the frequency response is
deliberately rolled off early, so it strikes me that this is by design and
therefore not a flaw.

To many, in pure engineering terms - and in pursuit of an ideal of the
truest representation of the source - this may be anathema but, to me, and I
suspect most hifi purchasers who listen before buying, when compared to
other products, I liked its "colour" more.

I have no trouble leaving it on, so this isn't a problem for me. While I
may be curious as to *why* this is the case, I don't really care that it
is so - I prefer it and that's all that's important.

Well, it does seem like a 'problem' to me as it implies that the
performance will drift about with room temperature, variations in the
music
power changing the temperatures of devices, etc.

This may well be the case - I don't have the means to test such changes,
although I don't perceive the obvious changes once it's up and running
compared with when it is initially powered up from cold.

KH in a recent issue of Hi Fi News did do some measurements that showed
that the distortion levels in some amps vary as they warm up. However
others don't do this. My recollection is that this has been a 'known'
possibility for decades. (I certainly worked on it when developing over 20
years ago!) Hence such things should in general be removable by correct
design in my experience. If the set sounds 'better' when 'warmed up' then
I'd prefer the design to give the 'better' performance almost from the
instant of switch-on. Not to have to leave the set on for a long time
first. Partly as this would be a minor irritation. Partly as, to me, it
seems like a sign that the designers have not investigated and tackled the
problem.

I don't know if this is true. My favourite amp isn't perfect - it hums a
little, but I don't mind because I don't hear that when the music's playing.
I'd be even happier if the amp sounded the same from the get go and was
silent when not in use. I seem to recall one manufacturer claiming that,
even when in standby, the power supply is still fed to much of their amps'
cicuitry to keep them "warm" so that they sounded good when fully powered
on. I thought that this was inefficient at the time but, compared with
leaving a class A amp on 24/7 it's probably a sensible compromise (if it
wasn't bull****!)

Slainte,

Jim

In article ,
JustMe wrote:
in my experience, the selection of a musical instrument will depend on a
tonal preference - I certainly found this when trying out pianos and
would chose the one that I liked the sound of most.

If, however, that piano that you so like was recorded and replayed through
a system which adds or subtracts, it will no longer produce the 'tone' you
chose it for.

--
*If God had wanted me to touch my toes, he would have put them on my knees

Dave Plowman London SW
To e-mail, change noise into sound.

in my experience, the selection of a musical instrument will depend on a
tonal preference - I certainly found this when trying out pianos and
would chose the one that I liked the sound of most.

If, however, that piano that you so like was recorded and replayed through
a system which adds or subtracts, it will no longer produce the 'tone' you
chose it for.

True, and I might have spent a fortune ensuring that the recording
accurately represented this tone.

But I still cannot dictate how someone else should listen to that music -
whether I recorded it or not.

In article ,
JustMe wrote:
If, however, that piano that you so like was recorded and replayed
through a system which adds or subtracts, it will no longer produce
the 'tone' you chose it for.

True, and I might have spent a fortune ensuring that the recording
accurately represented this tone.

Not so. Satisfactory equipment for both recording and reproducing needn't
cost a fortune. Indeed, going down the valve route for example is likely
to cost a great deal more.

But I still cannot dictate how someone else should listen to that music
- whether I recorded it or not.

No one should be *dictated* to about anything like this.
But that cuts both ways. ;-)

--
*Why doesn't Tarzan have a beard? *

Dave Plowman London SW
To e-mail, change noise into sound.

If, however, that piano that you so like was recorded and replayed
through a system which adds or subtracts, it will no longer produce
the 'tone' you chose it for.

True, and I might have spent a fortune ensuring that the recording
accurately represented this tone.

Not so. Satisfactory equipment for both recording and reproducing needn't
cost a fortune. Indeed, going down the valve route for example is likely
to cost a great deal more.

Read again - I didn't say you *had* to spend a fortune, I said I *might*
have. I was merely extending the point that I might be devastated to know
that, having put a great deal of resource into a recording, it wasn't being
appreciated as I had intended but that there would be nothing practical I
could do ensure wide circulation whilst enforcing its appreciation on
specific equipment.

But I still cannot dictate how someone else should listen to that music
- whether I recorded it or not.

No one should be *dictated* to about anything like this.

Then we agree!

But that cuts both ways. ;-)

Does it?

In article ,
JustMe wrote:
If, however, that piano that you so like was recorded and replayed
through a system which adds or subtracts, it will no longer produce
the 'tone' you chose it for.

True, and I might have spent a fortune ensuring that the recording
accurately represented this tone.

Not so. Satisfactory equipment for both recording and reproducing
needn't cost a fortune. Indeed, going down the valve route for example
is likely to cost a great deal more.

Read again - I didn't say you *had* to spend a fortune, I said I *might*
have. I was merely extending the point that I might be devastated to
know that, having put a great deal of resource into a recording, it
wasn't being appreciated as I had intended but that there would be
nothing practical I could do ensure wide circulation whilst enforcing
its appreciation on specific equipment.

I'm not sure I understand this. If the record/replay chain is doing a
decent job, then your much loved piano should sound as close as possible
when reproduced. As soon as you decide none of this matters, any chance of
this being the case goes out the window. So that much loved piano will
sound different - either better or worse according to your preference. But
if that piano had a 'perfect' tone, than it can only be worse.

But I still cannot dictate how someone else should listen to that
music - whether I recorded it or not.

No one should be *dictated* to about anything like this.

Then we agree!

But that cuts both ways. ;-)

Does it?

Yes. You can state your preferences without challenge. You can say you
prefer an acoustic horn gramophone and no one will worry.

However, it never seems to stop there. You've given all sorts of reasons
why you don't care how 'inaccurate' your system may be while still suiting
you. So these things become open to discussion.

--
*Give me ambiguity or give me something else.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , JustMe
wrote:
Some amps' frequency responses can alter during warm up. Whether
this is a reflection of poor design or the designer's intent is
another matter.

I'd be interested to know which models do this, and by how much, and
at what frequencies, this change occurs. Not something I have
encountered so far as I can recall.

It's an Alchemist Kraken integrated -
http://www.alchemisthifi.info/ranges...pd6_integrated
_amplifier.htm. It's a class A amp so runs hot (I don't know how much
the fact that the room temperature is 20 or 25 degrees effects an amp
that "idles" at about 55 degrees). I have noticed the same changes on
different examples of the same amp though, in different environments and
with different speakers. Recently I found an old review of the amp which
actually stated that the amp's frequency response fluctuated for several
hours before settling down -
http://www.alchemisthifi.info/ranges...integrated-rev
iew-hifichoice.jpg - I presume that this result was gathered through
measurement.

OK. Thanks for the above. The above does sound as if the operation of this
amp is, indeed, distinctly device-temperature dependent.

One of my favourite amps sounds *very* different when first powered
up, compared with when it's hot, to the degree that a demonstration
of it when cold would not impress me whilst, when warm, I love it.

Again, I'd be interested to hear the details.

See above. Like I say, I don't mind the fact that this happens, nor the
fact that, on paper the amp is noisy or gives "distortion", as I like
the amp more than the modest inconvenience of permenant power-up.

However, see the comment you make later on... :-)

I was at the hifi show in Manchester last week and overheard Eric
Kingdom from Sony talking about the digital Sony amps and talking about
the sound being "unusual" to some people because of the lack of
distortion introduced between source and speaker. He made the point
that, what a lot of people refer to as "musicality" was just colour and
distortion introduced by amps. I felt that this was probably right, but
it didn't make me prefer the Sony amp.

Not certain of his comments. For example, one reason the current 'digital'
amps may sound different is that they have to employ an LCL filter in their
output to stop the switching ultrasonics getting to the speaker at full
level. This filter then can alter the frequency response quite a lot in the
audio band with some speaker loads.

[snip]

There's no doubt that the Kraken amp is coloured, but that colour is one
of the things that I like about it - I enjoy the music more and so it
does what I've paid for. Even the amp's designer says that the frequency
response is deliberately rolled off early, so it strikes me that this is
by design and therefore not a flaw.

Again, see what you write later, though... :-)

[snip]

I'd be even happier if the amp sounded the same from the get go and was
silent when not in use.

This is the real point I was trying to make. If you prefer an amp with a
specific audible distortion or frequency response, etc, that's your
privilige. Similarly, the designer/maker can choose to offer that if they
also like it and feel some customers will do so. However if this *is*
your/their preference then I'd argue that it is their task to try and
ensure you get this *without* having an undue delay after switch-on.

To that extent, I'd say the design was 'flawed', although it may be a
'flaw' you are happy to live with, on balance.

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

Some amps' frequency responses can alter during warm up. Whether
this is a reflection of poor design or the designer's intent is
another matter.

I'd be interested to know which models do this, and by how much, and
at what frequencies, this change occurs. Not something I have
encountered so far as I can recall.

It's an Alchemist Kraken integrated -

http://www.alchemisthifi.info/ranges...pd6_integrated
_amplifier.htm. It's a class A amp so runs hot (I don't know how much
the fact that the room temperature is 20 or 25 degrees effects an amp
that "idles" at about 55 degrees). I have noticed the same changes on
different examples of the same amp though, in different environments and
with different speakers. Recently I found an old review of the amp which
actually stated that the amp's frequency response fluctuated for several
hours before settling down -

http://www.alchemisthifi.info/ranges...integrated-rev
iew-hifichoice.jpg - I presume that this result was gathered through
measurement.

OK. Thanks for the above. The above does sound as if the operation of this
amp is, indeed, distinctly device-temperature dependent.
One of my favourite amps sounds *very* different when first powered
up, compared with when it's hot, to the degree that a demonstration
of it when cold would not impress me whilst, when warm, I love it.

Again, I'd be interested to hear the details.

See above. Like I say, I don't mind the fact that this happens, nor the
fact that, on paper the amp is noisy or gives "distortion", as I like
the amp more than the modest inconvenience of permenant power-up.

However, see the comment you make later on... :-)

Getting there!

I was at the hifi show in Manchester last week and overheard Eric
Kingdom from Sony talking about the digital Sony amps and talking about
the sound being "unusual" to some people because of the lack of
distortion introduced between source and speaker. He made the point
that, what a lot of people refer to as "musicality" was just colour and
distortion introduced by amps. I felt that this was probably right, but
it didn't make me prefer the Sony amp.

Not certain of his comments. For example, one reason the current 'digital'
amps may sound different is that they have to employ an LCL filter in
their
output to stop the switching ultrasonics getting to the speaker at full
level. This filter then can alter the frequency response quite a lot in
the
audio band with some speaker loads.

I'm not technical enough to understand how this works. What he said sounded
plausible, but I certainly agreed with him about perceptions of
"musicality".

[snip]

There's no doubt that the Kraken amp is coloured, but that colour is one
of the things that I like about it - I enjoy the music more and so it
does what I've paid for. Even the amp's designer says that the frequency
response is deliberately rolled off early, so it strikes me that this is
by design and therefore not a flaw.

Again, see what you write later, though... :-)

Yup, soon...

[snip]

I'd be even happier if the amp sounded the same from the get go and was
silent when not in use.

This is the real point I was trying to make. If you prefer an amp with a
specific audible distortion or frequency response, etc, that's your
privilige. Similarly, the designer/maker can choose to offer that if they
also like it and feel some customers will do so. However if this *is*
your/their preference then I'd argue that it is their task to try and
ensure you get this *without* having an undue delay after switch-on.

I don't disagree. However I have not heard an amplifier which performs in a
way which, to my mind, equals or surpasses the Kraken integrated, at the
money. There are many things I would like it to do - remote control, greater
number of inputs, not hum so loudly, not centrally heat my room etc but, for
all that, it is still my favourite of the ~£500 amps I have heard (including
Audiolab, AMC, Arcam, Cyrus, IncaTec (sp? - was a while ago!) etc etc).

To that extent, I'd say the design was 'flawed', although it may be a
'flaw' you are happy to live with, on balance.

On balance, I am happy with the compromises although, I would say that, if
something operates a certain way *by design* then such operation cannot be
said to be a flaw. That's not to say that it cannot be improved upon.

As soon as someone can demonstrate an amplifier which delivers performance I
would rate as equal or superior, without the foibles listed above, my wallet
will be open )

Slainte,

Jim

Cheers!

In article ,
JustMe wrote:
I'm not technical enough to understand how this works. What he said
sounded plausible, but I certainly agreed with him about perceptions of
"musicality".

This is the bit of adspeak that always confuses me. The 'musicality'
comes from the instruments etc as recorded. If the equipment in use adds
'musicality' it's akin to someone playing a piano etc along with your
system. Which might just be fine sometimes, but you'd soon get tired of it.

--
*A picture may be worth a thousand words, but it uses up a thousand times more memory.

Dave Plowman London SW
To e-mail, change noise into sound.