In article , JustMe
wrote:


I will, once again, explain that the Alchemist amp DOES sound better and
that ANY statement of preference in sound-quality is, by its very
nature, a personal one. I can no more tell you what to prefer than you
can tell me and it would be arrogant and misguided to assume otherwise.

[snip]

If something is engineered to sound a certain way, then there is nothing
wrong with it when it performs as engineered. If it functions true to
its design then there is nothing "wrong" with the Kraken.

I have become curious about this as I had a vague recollection of having
seen reviews of the Kraken. Had a look though old mags, etc, this morning.
(Side-benefit was it meant I avoided having to start writing an exam paper.
;- )

Can't find a review in HFN although I thought one was published there.
However have found one in HFW. As usual, the results this gives are a bit
patchy and may well be misleading or erronious. However I also looked at
some reviews of other Alchemist amps, and the reports on the Kraken in the
review look consistent with the other comments.

What caught my eye was two factors.

One is that the distortion tends to rise as the power approaches the rated
output. The way this is described in the review makes me wonder if the
designer was deliberately aiming at 'soft' clipping behaviour.

The second was that, although measured to deliver 50W into 8 Ohm loads,
this fell to 36W into 4 Ohm loads. Again, it was mentioned that the
distortion tended to rise as this level was approached. This implies that
the available current may also 'soft' clip at a value that may come into
play with speakers that don't maintain an impedance of about 8 Ohms across
the band. (In such cases the rated power may be misleading as significantly
higher powers may be available but with higher levels of distortion than
used to rate the max available power. Alas this is one of the many things
the HFW review fails to specify.)

The distortion levels quoted were ranging up to 0.5 percent as the limiting
powers were approached. This may perhaps be high enough to be audible, but
I'd suspect not severe enough to be objectionable, or may well simply go
unnoticed as 'distortion'. However hard to say for sure without a lot more
info than the magazine gives, so can only speculate about this. Would also
depend, I suspect, a lot on the user and circumstances of use...

The result may perhaps be that the amp soft clips a bit, and this may alter
the sound - particularly with high power transients or extended bass. The
review comments on the bass being affected in ways that might be consistent
with this, and the reviewer indicates that some users may well like the
results.

I would have liked to see values for the o/p impedance, but the review does
not give this, or various other bits of info.

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

"Jim Lesurf" wrote in message
...
In article , JustMe
wrote:


I will, once again, explain that the Alchemist amp DOES sound better and
that ANY statement of preference in sound-quality is, by its very
nature, a personal one. I can no more tell you what to prefer than you
can tell me and it would be arrogant and misguided to assume otherwise.

[snip]

If something is engineered to sound a certain way, then there is nothing
wrong with it when it performs as engineered. If it functions true to
its design then there is nothing "wrong" with the Kraken.

I have become curious about this as I had a vague recollection of having
seen reviews of the Kraken. Had a look though old mags, etc, this morning.
(Side-benefit was it meant I avoided having to start writing an exam
paper.
;- )

Can't find a review in HFN although I thought one was published there.
However have found one in HFW. As usual, the results this gives are a bit
patchy and may well be misleading or erronious. However I also looked at
some reviews of other Alchemist amps, and the reports on the Kraken in the
review look consistent with the other comments.

What caught my eye was two factors.

One is that the distortion tends to rise as the power approaches the rated
output. The way this is described in the review makes me wonder if the
designer was deliberately aiming at 'soft' clipping behaviour.

The second was that, although measured to deliver 50W into 8 Ohm loads,
this fell to 36W into 4 Ohm loads. Again, it was mentioned that the
distortion tended to rise as this level was approached. This implies that
the available current may also 'soft' clip at a value that may come into
play with speakers that don't maintain an impedance of about 8 Ohms across
the band. (In such cases the rated power may be misleading as
significantly
higher powers may be available but with higher levels of distortion than
used to rate the max available power. Alas this is one of the many things
the HFW review fails to specify.)

The distortion levels quoted were ranging up to 0.5 percent as the
limiting
powers were approached. This may perhaps be high enough to be audible, but
I'd suspect not severe enough to be objectionable, or may well simply go
unnoticed as 'distortion'. However hard to say for sure without a lot more
info than the magazine gives, so can only speculate about this. Would also
depend, I suspect, a lot on the user and circumstances of use...

The result may perhaps be that the amp soft clips a bit, and this may
alter
the sound - particularly with high power transients or extended bass. The
review comments on the bass being affected in ways that might be
consistent
with this, and the reviewer indicates that some users may well like the
results.

I would have liked to see values for the o/p impedance, but the review
does
not give this, or various other bits of info.

Slainte,

Jim

Hi Jim,

You'll find links to three reviews of the Kraken Integrated (+ lots of other
info) he
http://www.alchemisthifi.info/ranges...pd6_integrated
_amplifier.htm#downloads

There is also info about the separate (and SUPERIOR!) Kraken pre & power
amps.

The comparisons I made were using a PC's line out as a source (both CD and
320kb/s MP3) and a pair of B&W LM1 speakers, at my desk, however I have made
similar comparisons using more "hifi" sources and superior speakers.

The pre/power amps are currently driving a pair of original Mission 752s
which
together sound staggeringly good.

What are you studying at the moment?

On Wed, 24 Nov 2004 09:40:39 -0000, "JustMe" wrote:

The comparisons I made were using a PC's line out as a source (both CD and
320kb/s MP3) and a pair of B&W LM1 speakers, at my desk, however I have made
similar comparisons using more "hifi" sources and superior speakers.

The pre/power amps are currently driving a pair of original Mission 752s
which
together sound staggeringly good.

A fine speaker, indeed. And Jim's research did indeed lead staright to
what's wrong with the Kraken - appalling current delivery! Into 4
ohms, it can only put out the voltage equivalent of 18 watts into 8
ohms. You just *know* that's going to be audible on peaks...........

OTOH, the effects decribed would be not unlike one of the classic
nonlinearities of valve amps, so that may be why you like it.

What are you studying at the moment?

He's a lecturer in electronics and physics at St Andrews University.
He's not filling in the exam paper, he's creating it.............

Yes, he knows what he's talking about.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...
On Wed, 24 Nov 2004 09:40:39 -0000, "JustMe" wrote:

The comparisons I made were using a PC's line out as a source (both CD
and
320kb/s MP3) and a pair of B&W LM1 speakers, at my desk, however I have
made
similar comparisons using more "hifi" sources and superior speakers.

The pre/power amps are currently driving a pair of original Mission 752s
which
together sound staggeringly good.

A fine speaker, indeed.

Whoops - I meant VM1s with regard to the B&Ws, although I doubt you were
referring to those as "fine" )

And Jim's research did indeed lead staright to
what's wrong with the Kraken - appalling current delivery! Into 4
ohms, it can only put out the voltage equivalent of 18 watts into 8
ohms. You just *know* that's going to be audible on peaks...........

In this particular setup (by my PC) it remains at a comparitively low
volume - I doubt I take it to anywhere near a level at which it'll clip,
even with variances from the speakers.

Again you say "what's wrong with the Kraken".

1) Do you know that this isn't by design?

(And I'm not asking for what *you* consider to be good design in an
amplifier, just whether you *know* if this is by design or not).

2) If I like what the amp does, then what is wrong with it, to me?

OTOH, the effects decribed would be not unlike one of the classic
nonlinearities of valve amps, so that may be why you like it.

I cannot comment on this, although I have only heard one or two valve amps
in such a context, so haven't the range of reference as I do with SS amps.

You might say that one man's "nonlinearity" is another man's "sweet".

What are you studying at the moment?

He's a lecturer in electronics and physics at St Andrews University.
He's not filling in the exam paper, he's creating it.............

I misinterpreted his statement.

Yes, he knows what he's talking about.

That is clear from Jim's posts. He also engages with interest, enthusiasm
and without condescension - I'm sure he's a very good teacher.

JustMe wrote:
"Stewart Pinkerton" wrote in message
...


And Jim's research did indeed lead staright to
what's wrong with the Kraken - appalling current delivery! Into 4
ohms, it can only put out the voltage equivalent of 18 watts into 8
ohms. You just *know* that's going to be audible on peaks...........


In this particular setup (by my PC) it remains at a comparitively low
volume - I doubt I take it to anywhere near a level at which it'll clip,
even with variances from the speakers.

Again you say "what's wrong with the Kraken".

1) Do you know that this isn't by design?

(And I'm not asking for what *you* consider to be good design in an
amplifier, just whether you *know* if this is by design or not).


Excuse me for jumping in, but going back to Jim's finding that,
"although measured to deliver 50W into 8 Ohm loads, this fell to 36W
into 4 Ohm loads", wouldn't this mean the amp was improperly specced or
designed? I am under the impression that most amps would deliver more
power (not necessarily double) into a 4 Ohm load than an 8 Ohm load.

In article , Tat Chan wrote:
JustMe wrote:
"Stewart Pinkerton" wrote in message
...
And Jim's research did indeed lead staright to
what's wrong with the Kraken - appalling current delivery! Into 4
ohms, it can only put out the voltage equivalent of 18 watts into 8
ohms. You just *know* that's going to be audible on peaks...........

In this particular setup (by my PC) it remains at a comparitively low
volume - I doubt I take it to anywhere near a level at which it'll clip,
even with variances from the speakers.

Again you say "what's wrong with the Kraken".

1) Do you know that this isn't by design?

(And I'm not asking for what *you* consider to be good design in an
amplifier, just whether you *know* if this is by design or not).

Excuse me for jumping in, but going back to Jim's finding that,
"although measured to deliver 50W into 8 Ohm loads, this fell to 36W
into 4 Ohm loads", wouldn't this mean the amp was improperly specced or
designed? I am under the impression that most amps would deliver more
power (not necessarily double) into a 4 Ohm load than an 8 Ohm load.

I guess it depends on your standards and how you look at things.

An "18 Watt/8 Ohm" amplifier which also drives 36 Watts into 4 Ohms
would achieve the usual modern standard [1]. Thus the Kraken could
be considered to be perfectly well designed to provide 18 Watts
into a nominally 6 Ohm loudspeaker (i.e. one with an impedance of 4
Ohms minimum).

It just wouldn't get the "50 Watt" label. However, that may be fine.
If the loudspeaker had a sensitivity of, say, = 93 dB at 1 metre for
a nominal 8 Ohm Watt then you could still get unclipped peak levels of
around 105 dB from an "18 Watt" amplifier - which would be fine for a
very reasonable range of music.

[1] Some amplifiers exceed this. The older Krells, for example, continue
doubling output power down to to 2 Ohms or even lower.

--
John Phillips

John Phillips wrote:

In article , Tat Chan wrote:



Excuse me for jumping in, but going back to Jim's finding that,
"although measured to deliver 50W into 8 Ohm loads, this fell to 36W
into 4 Ohm loads", wouldn't this mean the amp was improperly specced or
designed? I am under the impression that most amps would deliver more
power (not necessarily double) into a 4 Ohm load than an 8 Ohm load.


I guess it depends on your standards and how you look at things.

as long as my amp can drive my speakers, I'm happy ...

well, that would be one criteria anyway.



An "18 Watt/8 Ohm" amplifier which also drives 36 Watts into 4 Ohms
would achieve the usual modern standard [1].


yes, that sounds right. I got thrown off by the "50W into 8 Ohms" figure


Thus the Kraken could
be considered to be perfectly well designed to provide 18 Watts
into a nominally 6 Ohm loudspeaker (i.e. one with an impedance of 4
Ohms minimum).

so a speaker with a nominal impedance of 6 Ohm has as its minumum
impedance, 4 Ohms? I thought it could go below that at certain frequencies.



It just wouldn't get the "50 Watt" label. However, that may be fine.
If the loudspeaker had a sensitivity of, say, = 93 dB at 1 metre for
a nominal 8 Ohm Watt then you could still get unclipped peak levels of
around 105 dB from an "18 Watt" amplifier - which would be fine for a
very reasonable range of music.


yes, the Kraken would be fine for driving very efficient speakers at a
"reasonable" listening level.



[1] Some amplifiers exceed this. The older Krells, for example, continue
doubling output power down to to 2 Ohms or even lower.

So the newer Krells might not do this? Cost cutting reasons, or they
don't make them like they used to?

On 24 Nov 2004 23:56:20 GMT, John Phillips
wrote:

In article , Tat Chan wrote:
JustMe wrote:
"Stewart Pinkerton" wrote in message
...
And Jim's research did indeed lead staright to
what's wrong with the Kraken - appalling current delivery! Into 4
ohms, it can only put out the voltage equivalent of 18 watts into 8
ohms. You just *know* that's going to be audible on peaks...........

In this particular setup (by my PC) it remains at a comparitively low
volume - I doubt I take it to anywhere near a level at which it'll clip,
even with variances from the speakers.

Again you say "what's wrong with the Kraken".

1) Do you know that this isn't by design?

(And I'm not asking for what *you* consider to be good design in an
amplifier, just whether you *know* if this is by design or not).

Excuse me for jumping in, but going back to Jim's finding that,
"although measured to deliver 50W into 8 Ohm loads, this fell to 36W
into 4 Ohm loads", wouldn't this mean the amp was improperly specced or
designed? I am under the impression that most amps would deliver more
power (not necessarily double) into a 4 Ohm load than an 8 Ohm load.

I guess it depends on your standards and how you look at things.

An "18 Watt/8 Ohm" amplifier which also drives 36 Watts into 4 Ohms
would achieve the usual modern standard [1]. Thus the Kraken could
be considered to be perfectly well designed to provide 18 Watts
into a nominally 6 Ohm loudspeaker (i.e. one with an impedance of 4
Ohms minimum).

It just wouldn't get the "50 Watt" label. However, that may be fine.
If the loudspeaker had a sensitivity of, say, = 93 dB at 1 metre for
a nominal 8 Ohm Watt then you could still get unclipped peak levels of
around 105 dB from an "18 Watt" amplifier - which would be fine for a
very reasonable range of music.

[1] Some amplifiers exceed this. The older Krells, for example, continue
doubling output power down to to 2 Ohms or even lower.

On a point of information, Krells before the KAV series were always
specified as doubling rated power right down to 1 ohm. This isn't
repealing the laws of physics however, as my '50 watt' KSA-50 mk II
actually puts out 105 watts into 8 ohms, 195 watts into 4 ohms, and
does indeed drive 440 watts continuously into a 1 ohm load.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article , Tat Chan
wrote:

Excuse me for jumping in, but going back to Jim's finding that,
"although measured to deliver 50W into 8 Ohm loads, this fell to 36W
into 4 Ohm loads", wouldn't this mean the amp was improperly specced or
designed? I am under the impression that most amps would deliver more
power (not necessarily double) into a 4 Ohm load than an 8 Ohm load.

I think others have already explained this apparent puzzle in detail. But,
to confirm, yes, the problem may be that the amp in question cannot deliver
sustained (or peak) currents high enough to allow the power to double.

What is not clear from the reviews/reports I have seen on the Kraken is how
much this occurs with real musical waveforms as opposed to continuous
sinewaves... How much it may 'matter' depends on info we don't have, and
the choice of loudspeakers, music, etc...

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

Jim Lesurf wrote:

In article , Tat Chan
wrote:


Excuse me for jumping in, but going back to Jim's finding that,
"although measured to deliver 50W into 8 Ohm loads, this fell to 36W
into 4 Ohm loads", wouldn't this mean the amp was improperly specced or
designed? I am under the impression that most amps would deliver more
power (not necessarily double) into a 4 Ohm load than an 8 Ohm load.


I think others have already explained this apparent puzzle in detail. But,
to confirm, yes, the problem may be that the amp in question cannot deliver
sustained (or peak) currents high enough to allow the power to double.


Jim, John and Stewart, thanks for the explanations. I may have to hit
the books again, I can't believe how much stuff I have forgotten!