Every amp in one
 

JustMe wrote:


For performance rather than reproduction, I believe that Marshall do a
range of amps which have 'valvesound' simulators built in. OTOH, I'm
informed that they don't really sound the same as a classic valved
Marshall (shrug).


So then, from what you and others would say, the "filters" or "DSPs" used
now, are NOT able to accurately emulate other amps with accuracy and the
technology to do so may be some way off and/or be too expensive?



The POD I mentioned is a world apart from the "valvesound" ideas, but
still not perfect, but better than lugging 15 different amps around. I
haven't looked for some time, but the makers web site has assorted sound
clips of the different effects it can do.

I don't think you can make a guitar sound like its being played at loud
volumn, through a amp and speakers that are compressing the tops of the
wave without clipping them, without actually doing it, all three parts
the guitar (strings, body and pickup's), amp, and speakers are
intereacting to produce the result. If you DI a guitar, and then replay
that through a amp, you get quite a different effect. And for that
matter, its quite a different feeling playing a (say strat) guitar on
the edge of feedback, there is so much life in the strings, you are as
much keeping it on a leash as playing it.

Listen to some of the small sounds at the back of the mix in something
like Electric Ladyland, and consider how loud they must have actually
been played, esp as that was before amps with three controlable gain
stages (or even two) were about.

--
Nick

Every amp in one
 

"Nick Gorham" wrote in

The POD I mentioned is a world apart from the "valvesound" ideas, but
still not perfect, but better than lugging 15 different amps around. I
haven't looked for some time, but the makers web site has assorted sound
clips of the different effects it can do.

I don't think you can make a guitar sound like its being played at loud
volumn, through a amp and speakers that are compressing the tops of the
wave without clipping them, without actually doing it, all three parts the
guitar (strings, body and pickup's), amp, and speakers are intereacting to
produce the result. If you DI a guitar, and then replay that through a
amp, you get quite a different effect. And for that matter, its quite a
different feeling playing a (say strat) guitar on the edge of feedback,
there is so much life in the strings, you are as much keeping it on a
leash as playing it.

Listen to some of the small sounds at the back of the mix in something
like Electric Ladyland,



Hmmm, you'd need valve amplification and a decent vinyl rig to be able to do
that for a start!

Every amp in one
 

JustMe wrote:

So then, from what you and others would say, the "filters" or "DSPs" used
now, are NOT able to accurately emulate other amps with accuracy and the
technology to do so may be some way off and/or be too expensive?

Not necessarily. The main difficulty is in generating a suitable *model*
not in actually building hardware to implement it.

Every amp in one
 

Keith G wrote:
"Nick Gorham" wrote in


The POD I mentioned is a world apart from the "valvesound" ideas, but
still not perfect, but better than lugging 15 different amps around. I
haven't looked for some time, but the makers web site has assorted sound
clips of the different effects it can do.

I don't think you can make a guitar sound like its being played at loud
volumn, through a amp and speakers that are compressing the tops of the
wave without clipping them, without actually doing it, all three parts the
guitar (strings, body and pickup's), amp, and speakers are intereacting to
produce the result. If you DI a guitar, and then replay that through a
amp, you get quite a different effect. And for that matter, its quite a
different feeling playing a (say strat) guitar on the edge of feedback,
there is so much life in the strings, you are as much keeping it on a
leash as playing it.

Listen to some of the small sounds at the back of the mix in something
like Electric Ladyland,




Hmmm, you'd need valve amplification and a decent vinyl rig to be able to do
that for a start!




In fact thats a example of the damage that can be done by looking at
scopes. When the first masters were made of Electric Ladyland, the
engineers looked at the tape, and found all sorts of odd out of phase
signals on it, so they decided to fix it. When the resultant pressing
was heard by Hendrix, he was less than impressed, they had spent a lot
of time creating all the out of phase effects in the first place. Thats
why its the second pressing is the one to have, not the first.

--
Nick

Every amp in one
 

In article , Mike Gilmour
writes

"tony sayer" wrote in message
...
e

God made the *807*



Does he still make them?....
--
Tony Sayer


Nay verily nay he's gone ss (and if needed sources them from China :-)
I like the 807 as an audio valve and because many of the early marine
transmitters like Oceanspan etc. used the 807 for RF output,
drivers/modulators etc. Recall having shelves piled high with them...now
they are £40++ a shot )-:



We used to get thro them like they were going out of fashion years ago
on a medium wave pirate rig;))
--
Tony Sayer

Every amp in one
 

In article , Nick Gorham
wrote:
Keith G wrote:


Listen to some of the small sounds at the back of the mix in something
like Electric Ladyland,


Hmmm, you'd need valve amplification and a decent vinyl rig to be able
to do that for a start!


In fact thats a example of the damage that can be done by looking at
scopes. When the first masters were made of Electric Ladyland, the
engineers looked at the tape, and found all sorts of odd out of phase
signals on it, so they decided to fix it. When the resultant pressing
was heard by Hendrix, he was less than impressed, they had spent a lot
of time creating all the out of phase effects in the first place. Thats
why its the second pressing is the one to have, not the first.

I enjoy Hendrix a lot. Didn't know about EL being altered as you describe.
Interesting. These days I listen to his work on CD-A, though. (Or DVD-V).
Some of the phase effects, etc, seem to come over well using ESL's. :-)

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

Every amp in one
 

Nick Gorham wrote:

In fact thats a example of the damage that can be done by looking at
scopes. When the first masters were made of Electric Ladyland, the
engineers looked at the tape, and found all sorts of odd out of phase
signals on it, so they decided to fix it. When the resultant pressing
was heard by Hendrix, he was less than impressed, they had spent a lot
of time creating all the out of phase effects in the first place. Thats
why its the second pressing is the one to have, not the first.

I call BS.

looking at a scope with simple waveforms on you may be able to see
out-of-phaseness.

I challenge you to do so on a complex musical source.

Every amp in one
 

JustMe wrote:

"Stewart Pinkerton" wrote in message
...

On Sat, 20 Nov 2004 13:11:51 +1100, Tat Chan
wrote:



isn't the 8000LX just a "stripped down" version of the 8000S (no remote,
and no configurable operating mode)?

No, it has a compromised power supply, which IME is audible on tough
speaker loads.


I believe the on-paper spec was 60 watts as opposed to 75 watts for the "S"
which, I assume, is an effect of the lower-spec power supply.


The manual for the Tag 60iRv (Tag's version of the S) states the following

"rated output power - 60W into 8 ohms"
"typical output power - 72W into 8 ohms"

Every amp in one
 

On Sat, 20 Nov 2004 17:28:11 -0000, "JustMe" wrote:

"Stewart Pinkerton" wrote in message
.. .
On Fri, 19 Nov 2004 15:16:22 -0000, "JustMe" wrote:

"Ian Molton" wrote in message
...
JustMe wrote:

Many of you chaps believe that the Peter Walker(?) "straight-wire"
ideal
is
that which any "hifi" designer should aspire to construct.

Do you think that this is attainable?

To all intents and purposes it has been attained in all good SS amps
(And a handful of exceptional valve amps)

Please can you suggest some examples? (Hopefully I will know at least
one!)

Audiolab 8000S, and the 8000P power amp. Common enough, and
essentually 'blameless', as Doug Self would say.

Well I know these amps very well and used to own an 8000S, so I'd find that
to be a useful reference.

So, who's going to build me an Alchemist Kraken APD6aII filter for use with
an 8000S then?

That depends what was wrong with the Kraken! If it's not a simple FR
difference, then a filter isn't going to do it. From your description,
it sounds more likely that it was a combination of weak bass and high
distortion, either crossover or HF IMD. You could likely synthesise
this with a good DSP unit (and a good programmer!), but wouldn't it be
simpler just to buy another amp?

There's nothing wrong with the Kraken - I love it, it sounds better than the
Audiolab (see thread "Amp swap disappointment" for more).

Of course, there's something wrong with the Kraken, otherwise it would
sound like any other good amp! Please don't use terms like 'sounds
better', when what you mean is that *you* prefer some particular
nonlinearity.

I don't want to buy another amp - I'm going to flog the Audiolab shortly and
continue to enjoy the pleasures of the Kraken.
If you were to apply any simple description to the sound, it wouldn't be
weak bass, in my opinion, but rounded-off HF.

Fine, so that's your preference, no problem.

So then, from what you and others would say, the "filters" or "DSPs" used
now, are NOT able to accurately emulate other amps with accuracy and the
technology to do so may be some way off and/or be too expensive?

As noted, it depends what's wrong with the Kraken. It might be easily
simulated, or it might take a serious box of DSP tricks.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

On Sat, 20 Nov 2004 17:30:34 -0000, "JustMe" wrote:

"Stewart Pinkerton" wrote in message
.. .
On Sat, 20 Nov 2004 13:11:51 +1100, Tat Chan
wrote:

Stewart Pinkerton wrote:

On Fri, 19 Nov 2004 15:16:22 -0000, "JustMe" wrote:


"Ian Molton" wrote in message
...

JustMe wrote:


Do you think that this is attainable?

To all intents and purposes it has been attained in all good SS amps
(And a handful of exceptional valve amps)

Please can you suggest some examples? (Hopefully I will know at least
one!)


Audiolab 8000S, and the 8000P power amp. Common enough, and
essentually 'blameless', as Doug Self would say.

The OP has an Audiolab 8000LX. Shouldn't it be in the list as well? After
all,
isn't the 8000LX just a "stripped down" version of the 8000S (no remote,
and no
configurable operating mode)?

No, it has a compromised power supply, which IME is audible on tough
speaker loads.

I believe the on-paper spec was 60 watts as opposed to 75 watts for the "S"
which, I assume, is an effect of the lower-spec power supply.

And it's *much* worse into low impedance loads, which was a particular
strength of the 8000S.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

On Sat, 20 Nov 2004 20:00:03 -0000, "Keith G"
wrote:


"Nick Gorham" wrote in

The POD I mentioned is a world apart from the "valvesound" ideas, but
still not perfect, but better than lugging 15 different amps around. I
haven't looked for some time, but the makers web site has assorted sound
clips of the different effects it can do.

I don't think you can make a guitar sound like its being played at loud
volumn, through a amp and speakers that are compressing the tops of the
wave without clipping them, without actually doing it, all three parts the
guitar (strings, body and pickup's), amp, and speakers are intereacting to
produce the result. If you DI a guitar, and then replay that through a
amp, you get quite a different effect. And for that matter, its quite a
different feeling playing a (say strat) guitar on the edge of feedback,
there is so much life in the strings, you are as much keeping it on a
leash as playing it.

Listen to some of the small sounds at the back of the mix in something
like Electric Ladyland,

Hmmm, you'd need valve amplification and a decent vinyl rig to be able to do
that for a start!

I think you mean that you'd want to completely avoid valves and vinyl
for that.................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

Ian Molton wrote:
Nick Gorham wrote:

In fact thats a example of the damage that can be done by looking at
scopes. When the first masters were made of Electric Ladyland, the
engineers looked at the tape, and found all sorts of odd out of phase
signals on it, so they decided to fix it. When the resultant pressing
was heard by Hendrix, he was less than impressed, they had spent a lot
of time creating all the out of phase effects in the first place.
Thats why its the second pressing is the one to have, not the first.


I call BS.

looking at a scope with simple waveforms on you may be able to see
out-of-phaseness.

I challenge you to do so on a complex musical source.

Accepted, not wanting to be accused of bull**** (though this was just
ment to be a hopefully interesting "did you know"). I thought I would
try myself. yes I know he as left the building, but I still didn't want
the accusation to stick :-)

They did have some fun on that record, I can picture them, surrounded by
what was then (I guess) state of the art kit, finding ways to abuse it.

I wish I had my video camera on hand, anybody want to spend a few
minutes with a scope and has that recording, there is some quite OBVIOUS
out of phase information, try side one track one, "And the gods made love".

Anybody know of any PC stuff that could create a lissajous from a wav ?

--
Nick

Every amp in one
 

"tony sayer" wrote in message
...
In article , Mike Gilmour
writes

"tony sayer" wrote in message
...
e

God made the *807*



Does he still make them?....
--
Tony Sayer


Nay verily nay he's gone ss (and if needed sources them from China :-)
I like the 807 as an audio valve and because many of the early marine
transmitters like Oceanspan etc. used the 807 for RF output,
drivers/modulators etc. Recall having shelves piled high with them...now
they are £40++ a shot )-:



We used to get thro them like they were going out of fashion years ago
on a medium wave pirate rig;))
--
Tony Sayer


The 807 has a long history, whilst googling around I found a quote that said
the 807 was the valve that won the war!! ....2nd World War I presume :-)

Mike

Every amp in one
 

JustMe wrote:

Many of you chaps believe that the Peter Walker(?)
"straight-wire"
ideal
is
that which any "hifi" designer should aspire to construct.

Do you think that this is attainable?

To all intents and purposes it has been attained in all good SS
amps
(And a handful of exceptional valve amps)

Please can you suggest some examples? (Hopefully I will know at
least
one!)

Audiolab 8000S, and the 8000P power amp. Common enough, and
essentually 'blameless', as Doug Self would say.

Well I know these amps very well and used to own an 8000S, so I'd find
that
to be a useful reference.

So, who's going to build me an Alchemist Kraken APD6aII filter for use
with
an 8000S then?

That depends what was wrong with the Kraken! If it's not a simple FR
difference, then a filter isn't going to do it. From your description,
it sounds more likely that it was a combination of weak bass and high
distortion, either crossover or HF IMD. You could likely synthesise
this with a good DSP unit (and a good programmer!), but wouldn't it be
simpler just to buy another amp?

There's nothing wrong with the Kraken - I love it, it sounds better than
the
Audiolab (see thread "Amp swap disappointment" for more).

Of course, there's something wrong with the Kraken, otherwise it would
sound like any other good amp! Please don't use terms like 'sounds
better', when what you mean is that *you* prefer some particular
nonlinearity.

You know it's funny, but as I typed those words, I remembered an arguement I
had with you, maybe a year or two ago in which you made the same pedantic
point. I would say it was time for you to change the record, but you don't
use records, do you?

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.

If you accept that ANY judgement of "better", when discussing what is
undeniably a subjective issue, is personal, then you wont have the need to
stir up the same old argument about "opinion stated as fact" - which, no
doubt, would've been your next salvo - when it is clear that any opinion on
a subjective issue can ONLY be personal.

I could quite happily turn your argument around and quote your use of "any
other good amp". The Alchemist *is* good - in fact it is *better* than many
of the amps which you prefer :oP

Please don't use terms such as "any other good amp" when what you mean is
that *you* prefer sterile, uninspiring, unemotional, clinical, flat sound.

I don't want to buy another amp - I'm going to flog the Audiolab shortly
and
continue to enjoy the pleasures of the Kraken.
If you were to apply any simple description to the sound, it wouldn't be
weak bass, in my opinion, but rounded-off HF.

Fine, so that's your preference, no problem.

So then, from what you and others would say, the "filters" or "DSPs" used
now, are NOT able to accurately emulate other amps with accuracy and the
technology to do so may be some way off and/or be too expensive?

As noted, it depends what's wrong with the Kraken. It might be easily
simulated, or it might take a serious box of DSP tricks.

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.

Unless you are suggesting that each Kraken doesn't perform as intended?

Audio is Engineering

As you say...

Every amp in one
 

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

Every amp in one
 

"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?

Every amp in one
 

In article , JustMe
wrote:
"Jim Lesurf" wrote in message
...
[big snip]

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.

OK. Many thanks for the above links/info. I will investigate. I may also
take copies (if that is OK) of some items as I collect info on UK audio for
'historic' and reference purposes.

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.

This prompts me to see if I can find data on the impedance of the 752s as
that may be relevant here.

What are you studying at the moment?

I may be misunderstanding what prompted you to ask. However.. :-)

If it was my comment about 'exams', then I have this week been writing an
exam paper for an MSc class on 'Terahertz Technology'. I am 'retired'. But
as with many ancient/crumbling ex-academics, I do some teaching, etc, for
'theraputic' purposes. i.e. to give me something useful to do. ;-

That said, I spent an hour this morning chopping down a large tree. This
was probably better for me than writing the exam. :-)

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

Every amp in one
 

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

Every amp in one
 

"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" :o)

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.

Every amp in one
 

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.

Every amp in one
 

Jim Lesurf wrote:



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.)


Jim, I am confused here. I was under the impression that an amp will
deliver more power into a 4 Ohm load than into an 8 Ohm load.

If the amp delivers 50W into 8 Ohms,

then using P = (I^2) * R

I = sqrt (50/8) = 2.5 A


So, using a 4 OHm load, the amp should deliver

P = (2.5)^2 * 4 = 25 W


However if it was measured to deliver 36W into 4 Ohms,

then I = sqrt (36/4) = 3 A


So I take it the current the amp delivers can change with the load?
(apologies if this seems elementary, I haven't done these calculations
in a while!)

Every amp in one
 

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

Every amp in one
 

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?

Every amp in one
 

On Thu, 25 Nov 2004 10:15:48 +1100, Tat Chan
wrote:

Jim Lesurf wrote:



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.)


Jim, I am confused here. I was under the impression that an amp will
deliver more power into a 4 Ohm load than into an 8 Ohm load.

If the amp delivers 50W into 8 Ohms,

then using P = (I^2) * R

I = sqrt (50/8) = 2.5 A


So, using a 4 OHm load, the amp should deliver

P = (2.5)^2 * 4 = 25 W


However if it was measured to deliver 36W into 4 Ohms,

then I = sqrt (36/4) = 3 A


So I take it the current the amp delivers can change with the load?
(apologies if this seems elementary, I haven't done these calculations
in a while!)

It's simply that the amp has limits on both output voltage and ouput
current. 50 watts into 8 ohms represents the 20 Vrms limit of its
output voltage, while the 36 watts rating at 4 ohms indicates a low
current capability of only 3 amps.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

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

Every amp in one
 

On Wed, 24 Nov 2004 18:45:21 -0000, "JustMe" wrote:


"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" :o)

Correct - although they're fine as PC speakers.

And Jim's research did indeed lead straight 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?

I don't care. Any SET amp is bad 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).

See above. I'm using 'wrong' in the context of not sounding like any
other good amplifier. You may well like that 'wrongness', indeed you
have so stipulated.

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

Nothing, for you.

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".

Indeed, but if seeking a repacement, it's helpful to know *why* the
one you like, sounds the way it does.

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.


--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

In article , Stewart
Pinkerton
wrote:

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.

Well, the reports that I've now read from the URL that 'JustMe' gave seem
to contradict the HFW review in some respects, so the situation is not
entirely clear.

One 'nice' thing from my POV is that one of the other reviews comments to
the effect that the Kraken is designed to 'soft clip' so my guess on that
may be correct.

There are also - apparently - at least two versions of the Kraken, and
their behaviours may differ. One review (HFC) comments that the version
under test delivers more current (5.5A) than a previous version. They also
say they got a dynamic power of 90W into 4 Ohms.

The review in HFW (Sept 92) said the power was 50W/8Ohms but just
36W/4Ohms. However NK commented that this was distortion limited, so the
actual available power may be higher.

Taking the HFW values literally implies limits of 20Vrms (2.5Arms) into
8Ohms and 12Vrms (3Arms) into 4 Ohms if I calculate correctly.

The claimed 90W into 4 Ohms in the HFC review implies (assuming they mean
short-burst mean power) 18.9Vrms (4.7Arms). The 4.7Arms for a sinewave
implies a peak current of 6.7A which is above the 5.5A value they quote.

Taken at face value, the results seem inconsistent in detail, but make me
suspect two things:

1) That the amp and PSU can deliver higher currents and voltages for short
bursts than for sustained delivery.

2) That the o/p impedance may be 'high' - i.e. above 0.1 Ohms.

One report says the distortion level and frequency response alter as the
amp warms up. This may mean it is a low feedback design, which seems
consistent with (2).

Hence I suspect that this amp may be one that at times measures less well
with continuous sinewaves than it actually performs on music. Can't be sure
though, for the usual reasons - i.e. the reviews may simply contain errors
of fact, and certainly omit details that would tell us more.

BTW Afraid I found the website awkward to use. e.g. Data in large (6MB in
one case) PDFs that are essentially large bitmaps scans of the pages. Not a
very efficient way to provide a few pictures and some lines of text.
Interesting data, but I wish it had been provided as simple HTML, etc.
Took ages to download on my old dial-up connection. Then involved
manipulating 35MB+ bitmaps to read/print. :-/

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.

My wife might disagree. Depends upon whether I'm agreeing with her, or
not... :-)

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

Every amp in one
 

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

Every amp in one
 

In article , Tat Chan
wrote:
Jim Lesurf wrote:



The second was that, although measured to deliver 50W into 8 Ohm
loads, this fell to 36W into 4 Ohm loads.

So I take it the current the amp delivers can change with the load?
(apologies if this seems elementary, I haven't done these calculations
in a while!)

The higher resistance loads may mean the amp voltage limits before the
maximum current it can deliver is required. This is almost unavoidable at
some point. Just that Krell and some others put this point well below 4
Ohms, and others do not. :-)

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

Every amp in one
 

In article , Tat Chan wrote:
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.

I thought not, BICBW.

[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?

I have only seen the specs for KSA-80s and other Krells of that vintage,
and this is what I recall, so I cannot say anything for more modern Krell
amplifiers. SP says the doubling goes down to 1 Ohm with the KSA-50.

--
John Phillips

Every amp in one
 

In message , Stewart
Pinkerton writes
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.

Not staying in Class-A of course :-)
--
Chris Morriss

Every amp in one
 

"Jim Lesurf" wrote in message
...
In article , Stewart
Pinkerton
wrote:

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.

Well, the reports that I've now read from the URL that 'JustMe' gave seem
to contradict the HFW review in some respects, so the situation is not
entirely clear.

One 'nice' thing from my POV is that one of the other reviews comments to
the effect that the Kraken is designed to 'soft clip' so my guess on that
may be correct.

There are also - apparently - at least two versions of the Kraken, and
their behaviours may differ. One review (HFC) comments that the version
under test delivers more current (5.5A) than a previous version. They also
say they got a dynamic power of 90W into 4 Ohms.

The Kraken itself is inside a half-width case, with an external transformer
in a case of its own.

Originally the Kraken was supplied with a single torriodal transformer
inside this case, with room for a second transformer, as a sonic upgrade.
Later models were supplied with the dual transformer PSU as standard. Might
these differences be the cause of the review contradictions?

The review in HFW (Sept 92) said the power was 50W/8Ohms but just
36W/4Ohms. However NK commented that this was distortion limited, so the
actual available power may be higher.

Taking the HFW values literally implies limits of 20Vrms (2.5Arms) into
8Ohms and 12Vrms (3Arms) into 4 Ohms if I calculate correctly.

The claimed 90W into 4 Ohms in the HFC review implies (assuming they mean
short-burst mean power) 18.9Vrms (4.7Arms). The 4.7Arms for a sinewave
implies a peak current of 6.7A which is above the 5.5A value they quote.

Taken at face value, the results seem inconsistent in detail, but make me
suspect two things:

1) That the amp and PSU can deliver higher currents and voltages for short
bursts than for sustained delivery.

2) That the o/p impedance may be 'high' - i.e. above 0.1 Ohms.

One report says the distortion level and frequency response alter as the
amp warms up. This may mean it is a low feedback design, which seems
consistent with (2).

Hence I suspect that this amp may be one that at times measures less well
with continuous sinewaves than it actually performs on music. Can't be
sure
though, for the usual reasons - i.e. the reviews may simply contain errors
of fact, and certainly omit details that would tell us more.

BTW Afraid I found the website awkward to use. e.g. Data in large (6MB in
one case) PDFs that are essentially large bitmaps scans of the pages. Not
a
very efficient way to provide a few pictures and some lines of text.

Sorry about this. Most of the scans and specs are my own, which I try to
list as (still large) JPEGs. Because the site is an "archive", I've tried to
preserve the original source material and make that available, rather then
provide transcripts. To my mind, the originals reviews, brochures and
instruction manuals hold greater authenticity and are more interesting
artefacts.

The large PDFs you refer to are created from scans of the original product
brochures, which I believe are fairly rare. I don't believe that these
contain any further spec. not otherwise listed as text (laid out in tables)
on the product pages themselves. The brochures are curios and as a part of
the sites "archive" function. If spec in a brochure is not viewable as text
on a given product's page, please let me know and I'll update the page in
question.

I could use some OCR software to provide transcripts in parallel, but the
time required to carefully proof and edit these (given the surface quality
of much of the source material) isn't available to me right now, and this
would still be my second choice compared with offering the original
material.

Occassionally, someone is kind enough to create their own scan and send it
to me too. Often these are great, occassionally they aren't.

Interesting data, but I wish it had been provided as simple HTML, etc.
Took ages to download on my old dial-up connection. Then involved
manipulating 35MB+ bitmaps to read/print. :-/

Really? I'm not aware of any Kraken-related file larger than 4MB -
"kraken_mk2_brochure.pdf". Admittedly this is large, but it is a separate
"download" and not embedded onto any one page. I've just checked and the
entire site is 54MB, so am uncertain which file you are referring to -
please advise.

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.

My wife might disagree. Depends upon whether I'm agreeing with her, or
not... :-)

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

Every amp in one
 

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!

Every amp in one
 

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.

OK. Many thanks for the above links/info. I will investigate. I may also
take copies (if that is OK) of some items as I collect info on UK audio
for
'historic' and reference purposes.

No worries - the info is there for precisely that function.

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.

This prompts me to see if I can find data on the impedance of the 752s as
that may be relevant here.

They are known to be efficient - 91dB, nominally 8 ohms on paper. I don't
have data beyond that, but they were well-reviewed in their day (mid 90s),
so I'm sure there's plenty of into out there. IIRC HiFi World listed them as
"valve-amp friendly" for their efficiency.

What are you studying at the moment?

I may be misunderstanding what prompted you to ask. However.. :-)

If it was my comment about 'exams',

It was :o)

then I have this week been writing an
exam paper for an MSc class on 'Terahertz Technology'. I am 'retired'. But
as with many ancient/crumbling ex-academics, I do some teaching, etc, for
'theraputic' purposes. i.e. to give me something useful to do. ;-

That said, I spent an hour this morning chopping down a large tree. This
was probably better for me than writing the exam. :-)

You know you're still a man if you can chop down a tree!

Slainte,

Jim

Every amp in one
 

"Chris Morriss" wrote in message
...
In message , Stewart
Pinkerton writes
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.

Not staying in Class-A of course :-)

The Kraken amp is Class-A, BTW - it just occured to me that most people here
are not familiar with it and I that I haven't mentioned this previously.

Every amp in one
 

"Stewart Pinkerton" wrote in message
...
On Wed, 24 Nov 2004 18:45:21 -0000, "JustMe" wrote:


"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" :o)

Correct - although they're fine as PC speakers.

At one point I was driving them with a three box amp - Kraken pre amp and a
pair of bridged Kraken power amps (claimed 165 watts/ channel Class A) :-O

And Jim's research did indeed lead straight 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?

I don't care. Any SET amp is bad 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).

See above. I'm using 'wrong' in the context of not sounding like any
other good amplifier. You may well like that 'wrongness', indeed you
have so stipulated.

Well then this is a debate about semantics, which isn't really relevant. At
least I know where you're coming from.

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

Nothing, for you.

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".

Indeed, but if seeking a repacement, it's helpful to know *why* the
one you like, sounds the way it does.

Luckily I'm not seeking a replacement at this time.

Every amp in one
 

On Thu, 25 Nov 2004 21:16:56 +0000, Chris Morriss
wrote:

In message , Stewart
Pinkerton writes
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.

Not staying in Class-A of course :-)

Absolutely not! Often skated over by enthusiastic reviewers, but like
any other 'class A' amplifier, it operates in class A only up to it's
rated output of 50 watts into 8 ohms, i.e. 2.5 amps output current.
Ask for more current, and of course it begins to work in class AB.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

On Fri, 26 Nov 2004 02:32:02 -0000, "JustMe" wrote:

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

This prompts me to see if I can find data on the impedance of the 752s as
that may be relevant here.

They are known to be efficient - 91dB, nominally 8 ohms on paper. I don't
have data beyond that, but they were well-reviewed in their day (mid 90s),
so I'm sure there's plenty of into out there. IIRC HiFi World listed them as
"valve-amp friendly" for their efficiency.

IMNVHO, the best speaker they made since the original Chartwell-driver
batch of 770s.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

On Fri, 26 Nov 2004 02:33:51 -0000, "JustMe" wrote:


"Chris Morriss" wrote in message
...
In message , Stewart
Pinkerton writes
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.

Not staying in Class-A of course :-)

The Kraken amp is Class-A, BTW - it just occured to me that most people here
are not familiar with it and I that I haven't mentioned this previously.

Anything that runs *that* hot, had damn well better have lots of bias
by deliberate intent!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Every amp in one
 

"Stewart Pinkerton" wrote in message
...
On Fri, 26 Nov 2004 02:32:02 -0000, "JustMe" wrote:

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

This prompts me to see if I can find data on the impedance of the 752s
as
that may be relevant here.

They are known to be efficient - 91dB, nominally 8 ohms on paper. I don't
have data beyond that, but they were well-reviewed in their day (mid
90s),
so I'm sure there's plenty of into out there. IIRC HiFi World listed them
as
"valve-amp friendly" for their efficiency.

IMNVHO, the best speaker they made since the original Chartwell-driver
batch of 770s.

I haven't heard every speaker that they have ever released, but have heard
most from the last 10 years and many from the years before.
They are - to my ears - the best speakers Mission have made to date.