"JustMe" wrote in message


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

Yep, people such as me.

Do you think that this is attainable?

For me it's not a matter of believing, is a matter of experiencing it.

I've done a lot of straight-wire bypass testing of audio gear and am
therefore intimately familiar with the results.

"JustMe" wrote in message


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

How about providing audio files made with regular commercial audio gear,
before and after?

http://www.pcabx.com/product/amplifiers/index.htm

http://www.pcabx.com/product/soundcard/index.htm

Hi,

In message , Nick Gorham
writes
JustMe wrote:
In the "Amp swap disappointment" thread, below, Ian has said that it's
possible to accurately measure the differences between each amp and, I would
assume, judge just what it is about one amp that might make it preferable to
another amp, to some listeners.
Would it therefore be possible for someone to take a "straight-line"
amp -
and I'm happy to accept whatever you judge to be a representation of the
closest example of this - and then build an add on "filter" to alter its
sound to reproduce the sound quality of the Alchemist?
Then, maybe, a dozen or so other popular amps could be measured, and
filters
built to represent each amp in turn.
Would I be able to hear the difference between the "straight-line"
amp with
the Alchemist filter and the Alchemist amp?


This is the guitar amp version of what you are talking about

http://www.kellyindustries.com/guitars/line_6_pod.html

.... And the microphone preamp version is he
http://www.ffliquid.com/home.html

Cool technology - convolution techniques used to emulate vintage
preamps, and downloadable models. I got a demo at this years Video
Forum, and it seemed pretty impressive. But.. you have to take anything
you hear on a trade-show floor with a large pinch of salt, because it's
too damned loud to hear properly, so don't quote me.
--
Regards,
Glenn Booth

Hi,

In message , Ian Molton
writes
JustMe wrote:

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

Theres a bit of a gap betwixt theory and practice here... whilst linear
amps arent theoretical, the 'amp emulator' is and would need
considerable research to get right.

I think the technology exists, but it isn't going to be cheap. You'd
need to model the amp (probably using convolution, by measuring impulse
responses), a la Focusrite's Liquid Channel, and then use a bucketload
of DSP to implement the model. The DSP engine and software would
probably cost more than the amp, and therefore defeat the object. SHARC
DSP chips might be two a penny in ten years though.

Then of course you'd have the audiophile argument about the 'colour'
introduced by the DSP unit itself...

--
Regards,
Glenn Booth

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)?

"Arny Krueger" wrote in message
...
"JustMe" wrote in message


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

Yep, people such as me.

Do you think that this is attainable?

For me it's not a matter of believing, is a matter of experiencing it.

I've done a lot of straight-wire bypass testing of audio gear and am
therefore intimately familiar with the results.


Arnie, you stupid mutt. Can't you get it into your
head that the reason you can't hear differences in
your tests is that the tests are not sufficiently
sensitive. Serial tests do not reveal subtle differences.

In article , Glenn Booth
wrote:
Hi,

In message , Ian Molton
writes
JustMe wrote:

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

Theres a bit of a gap betwixt theory and practice here... whilst linear
amps arent theoretical, the 'amp emulator' is and would need
considerable research to get right.

I think the technology exists, but it isn't going to be cheap. You'd
need to model the amp (probably using convolution, by measuring impulse
responses), a la Focusrite's Liquid Channel, and then use a bucketload
of DSP to implement the model.

The snag, I think, is that the above assumes linear superposition is
applicable. This may not be the case, depending upon the nature of any
distortion mechanisms.

IIRC speaker manufacturers and reviewers swiftly stopped using impulse
functions for FFT-based analysis for this reason. The impulse tended to
suffer more from nonlinear effects than max-length 'noise' equivalents.

Rather than try and 'automate' a general process like the above, it would
probably make more sense to perform some suitable measurements, then apply
some human intelligence to deduce/guess a possible near-equivalent 'effect'
in cases where that looked feasible given the understanding available.

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

On Fri, 19 Nov 2004 18:25:23 -0000, "JustMe" wrote:

"Stewart Pinkerton" wrote in message
news
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?

I presume such a filter could be built to be inserted via the 8000S's
pre-power loop, enabling a very simple switch between "8000S straight-line
integrated" and "8000S Pre/Power/Alchemist mode" )

I'm happy to provide the amp for measurement and, from what I've read,
Stewart will be glad to provide an environment for a double-blind test ;o)

Sure, although I'm not sure that fiddling with filters is going to
give you what you're looking for. If you really do want 'character' in
your amplifier, perhaps you should look at single-ended valve designs.

BTW I'm not making any claims to right/wrong on any issue here, but I find
this a very interesting concept and, to me at least, the results of such a
test would have a profound impact on the way I would look at different amps
and the choices made by those who design and build hifi products. It would
also make an interesting article for a decent hifi mag and a good website
too.

Of course, some of you may think that this is nothing new and an unrealistic
quest, but I'm not aware of a hifi product "simulator" and would be glad to
buy one at a reasonable price, if it worked accurately.

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).
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sat, 20 Nov 2004 07:06:20 +0000 (UTC), "Alan Murphy"
wrote:

"Arny Krueger" wrote in message
...
"JustMe" wrote in message


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

Yep, people such as me.

Do you think that this is attainable?

For me it's not a matter of believing, is a matter of experiencing it.

I've done a lot of straight-wire bypass testing of audio gear and am
therefore intimately familiar with the results.


Arnie, you stupid mutt. Can't you get it into your
head that the reason you can't hear differences in
your tests is that the tests are not sufficiently
sensitive. Serial tests do not reveal subtle differences.

They reveal more subtle differences than do any other kind of test,
which is why top-class manufacturers such as Revel use them every day
in R&D. Of course, they won't reveal 'differences' which don't really
exist in the physical world. For that, you need sighted tests........

Science is no substitute for a vivid imagination!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

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.
--

Stewart Pinkerton | Music is Art - Audio is Engineering