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)

"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!)

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.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"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?

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)

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.

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.

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

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

Stewart Pinkerton 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).

Probably because the classic sound of a valve guitar amp going into overload
is mainly a power amp and speakers thing. The 'chainsaw' sound of overdriven
preamp stages is a different sound, and perhaps easier to simulate in SS
than the o/p distortion.

I've used a few SS distortion boxes which have provided a good basis for a
heavy metal sound - not too far from the overdrive preamp in one of my valve
amps. Can't say I've ever played through a tranny power amp and got a sound
like a valve power amp on the edge - it's a sweet spot thing where the amp
is as much a part of the instrument as the guitar itself.


--
Wally
www.artbywally.com
www.wally.myby.co.uk

"Stewart Pinkerton" wrote in message
...
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

Agreed - it's no where near the sound of the classic valved Marshalls - so
maybe emulating that 'sound' is not that easy to implement in an affordable
way.
Many of the guitar players I've met at International Jazz Festivals (for
broadcast or recording) either bring their own (generally) valved or
stipulate that in condition of hire. No 'shrug' needed the original
Marshalls have a goosebump sound (though I haven't a clue how it measures or
compares DBX wise ;-)

Mike

God made the *807*