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.