Every amp in one
 

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?

Every amp in one
 

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

--
Nick

Every amp in one
 

"JustMe" wrote in message
...
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.

**A reasonable assumption. Of course, the measurements need to be VERY
comprehensive. Far more comprehensive than those supplied by almost every
amplifier manufacturer.


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?

**Maybe. Maybe your Alchemist already IS a straight line amplifier. If it
has problems, it would be possible to duplicate those problems - at a cost,
of course.


Then, maybe, a dozen or so other popular amps could be measured, and
filters
built to represent each amp in turn.

**Yes. It would be difficult, but doable.


Would I be able to hear the difference between the "straight-line" amp
with
the Alchemist filter and the Alchemist amp?

**Not if it has been done right.


--
Trevor Wilson
www.rageaudio.com.au

Every amp in one
 

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.

Correct.

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?

yes.

Then, maybe, a dozen or so other popular amps could be measured, and filters
built to represent each amp in turn.

You could do this.

Would I be able to hear the difference between the "straight-line" amp with
the Alchemist filter and the Alchemist amp?

Assuming the alchemist distorts in some way (you say that it makes an
audible difference elsewhere, so I assume it does), yes.

Every amp in one
 

In article , 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?

In principle, yes, although the definition of what is required would
probably have to be broader than a 'filter'. In practice, difficult, as a
number of properties may be involved. Some may not be correctly identified,
and others may depend upon the conditions of use.

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?

Can't say as it would presumably depend upon how well the "filter" actually
represents the totality of the processes the Alchemist is performing.

What you *could* do, though is something like the following.

Play music through the Alchemist into a pair of speakers. While doing so,
connect leads to the speaker terminals and record the signals there onto
CD-R using a reasonably quality recorder. Note the signal level with a
meter.

The replay the recorded version of the signals using a different amp that
is known to have a flat response, low distortion, and low output impedance,
adjusing the level at the speakers to be as before. Then judge how similar
it sounds.

Repeat this process, but reversing the positions of the amps. Or using one
of them 'twice'. Compare, contrast, discuss. :-)

Alternatively, it would be possible in principle to do a 'live' version of
the above and avoid recording, although this would be more complex to set
up. Might make it easier to do a 'blind' check, though...

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
 

"Ian Molton" wrote in message
...
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.

Correct.

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?

yes.

Then, maybe, a dozen or so other popular amps could be measured, and
filters
built to represent each amp in turn.

You could do this.

Would I be able to hear the difference between the "straight-line" amp
with
the Alchemist filter and the Alchemist amp?

Assuming the alchemist distorts in some way (you say that it makes an
audible difference elsewhere, so I assume it does), yes.

I find this very interesting!

The consensus is that this is perfectly possible.

So, someone could build an amp which mimics the qualities of other amps,
simply by accurately measuring various aspects of the amps to be mimicked
and applying filters appropriately.

Could these filters be placed onto an IC and switched on the front panel?

That way, I can have my "straight-wire" amp and switch between "Alchemist
APD6a" mode, "Keith's Chinese valve amp" mode, "Audiolab 8000LX" mode,
"Cyrus V" mode, etc.

Nick points to a box which seems to not only reproduce the qualities of
amps, but speakers too.

How can this be? Surely a speaker's performance is influenced heavily by the
amp's ability to drive it well and by the acoustics of the environment in
which it is placed?

Every amp in one
 

JustMe wrote:

I find this very interesting!

The consensus is that this is perfectly possible.

No reason why not really.

Could these filters be placed onto an IC and switched on the front panel?

I'd be inclined to use a decent DSP and allow it to be programmed from a
PC personally...

That way, I can have my "straight-wire" amp and switch between "Alchemist
APD6a" mode, "Keith's Chinese valve amp" mode, "Audiolab 8000LX" mode,
"Cyrus V" mode, etc.

Yup.

Nick points to a box which seems to not only reproduce the qualities of
amps, but speakers too.

How can this be?

I dont see how it can be since to do so the box would need to have
knowledge of (at least) your room acoustics and speaker properties, and
(preferably) the room characteristics the 'target' speaker is used in.

(on top of that you'd need a profile for the other speaker, of course.)

Every amp in one
 

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?

In principle, yes, although the definition of what is required would
probably have to be broader than a 'filter'. In practice, difficult, as a
number of properties may be involved. Some may not be correctly
identified,
and others may depend upon the conditions of use.

Accepted. I use the term "filter" for simplicity but, I'd imagine that you'd
have to measure more than just the amp's frequency response. It would have
to be a "filter" constructed on the amp's performance at a given time - say
when the amp was perceived to be operating at its best.

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?

Can't say as it would presumably depend upon how well the "filter"
actually
represents the totality of the processes the Alchemist is performing.

What you *could* do, though is something like the following.

Play music through the Alchemist into a pair of speakers. While doing so,
connect leads to the speaker terminals and record the signals there onto
CD-R using a reasonably quality recorder. Note the signal level with a
meter.

The replay the recorded version of the signals using a different amp that
is known to have a flat response, low distortion, and low output
impedance,
adjusing the level at the speakers to be as before. Then judge how similar
it sounds.

Repeat this process, but reversing the positions of the amps. Or using one
of them 'twice'. Compare, contrast, discuss. :-)

Alternatively, it would be possible in principle to do a 'live' version of
the above and avoid recording, although this would be more complex to set
up. Might make it easier to do a 'blind' check, though...

I would be happy to try something like this blind. I'd be really curious to
see if such "filters" were possible and whether I would be able to tell
differences, or recognise my favourites as superior to those which I'd
previously rejected.

Presumably the playback equipment would have to be that which is considered
as "straight-line" - the CD player and amp? But is there a danger of a
cumulative effect? If I use the same speakers in replaying the signal as
it's been recorded from the system, would the effects of the speaker's
balance not be duplicated? Would this be cumulative? Presumably, any small
deviance from "straight-line" in the CD or amp's replay would undermine such
an experiment.

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?

Slainte,

Jim

Cheers!

Every amp in one
 

"JustMe" wrote in message


So, someone could build an amp which mimics the qualities of other
amps, simply by accurately measuring various aspects of the amps to
be mimicked and applying filters appropriately.

More specifically and technically, the adjustment facility for amplifier
mimicry would be a combination of linear and non-linear compensators.

A regular audio equalizer (parametric preferred, graphic accepted) would be
a kind of linear compensator.

There are no common high fidelity audio components that are intended to be
nonlinear compensators. The *Pod* device someone else mentioned may be an
example of such a device. However, its generally pretty sonically deadly to
put a complete musical signal through a highly nonlinear device because of
all of the non-harmonic spurious responses. When nonlinear devices are used,
they are usually used with just one voice or just one instrument.

If I was going to try to make a chameleon amplifier, I would start out with
a good clean pro audio type amp ( Hafler, Crown, QSC). I would front end it
with a 5-band parametric eq per channel. I might add a back-end device that
would provide a variable, perhaps even frequency-dependent source impedance
for the loudspeaker.

In use, I would try to duplicate the speaker voice-coil voltage of the amp
being *duplicated* by intelligent adjustment of the source impedance
simulator, and then fine tune the results with the parametric eq(s).

Wise audiophiles wishing to get off the new amplifier merry-go-round would
cut to the chase and just get some parametric eqs for their own system. Then
(and here is the hard part) they would learn to adjust them properly by ear.

Every amp in one
 

So, someone could build an amp which mimics the qualities of other
amps, simply by accurately measuring various aspects of the amps to
be mimicked and applying filters appropriately.

More specifically and technically, the adjustment facility for amplifier
mimicry would be a combination of linear and non-linear compensators.

A regular audio equalizer (parametric preferred, graphic accepted) would
be
a kind of linear compensator.

There are no common high fidelity audio components that are intended to be
nonlinear compensators. The *Pod* device someone else mentioned may be an
example of such a device. However, its generally pretty sonically deadly
to
put a complete musical signal through a highly nonlinear device because of
all of the non-harmonic spurious responses. When nonlinear devices are
used,
they are usually used with just one voice or just one instrument.

If I was going to try to make a chameleon amplifier, I would start out
with
a good clean pro audio type amp ( Hafler, Crown, QSC). I would front end
it
with a 5-band parametric eq per channel. I might add a back-end device
that
would provide a variable, perhaps even frequency-dependent source
impedance
for the loudspeaker.

In use, I would try to duplicate the speaker voice-coil voltage of the amp
being *duplicated* by intelligent adjustment of the source impedance
simulator, and then fine tune the results with the parametric eq(s).

Wise audiophiles wishing to get off the new amplifier merry-go-round would
cut to the chase and just get some parametric eqs for their own system.
Then
(and here is the hard part) they would learn to adjust them properly by
ear.

This probably comes down to semantics: do you view an audiophile as someone
who specifically seeks "straight-wire" sound, or is an audiophile anyone who
is critical of, seeks out and appreciates what they perceive to be superior
sound?

If the former then wouldn't they be better off purchasing the
"straight-wire" source, amp and speakers, and not playing with eqs to
compensate for the inferiority of "curly-wire" products?

If the latter then how can you quantify what is a "proper" adjustment of an
eq, beyond whatever the listener prefers?

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)

Every amp in one
 

JustMe wrote:

If the latter then how can you quantify what is a "proper" adjustment of an
eq, beyond whatever the listener prefers?

Its just a tool. you can use it compensate for deficiencies in your
system. eg. speakers with poor frequency repsonse or a nasty room accoustic.

Every amp in one
 

"JustMe" wrote in message



"Arny Krueger" wrote in message



Wise audiophiles wishing to get off the new amplifier merry-go-round
would cut to the chase and just get some parametric eqs for their
own system. Then (and here is the hard part) they would learn to
adjust them properly by ear.

This probably comes down to semantics: do you view an audiophile as
someone who specifically seeks "straight-wire" sound, or is an
audiophile anyone who is critical of, seeks out and appreciates what
they perceive to be superior sound?

It's obviouisly highly naive to believe that you're going to pick equipment
that has ideal response in your listening room without some kind of further
adjustment.

If the former then wouldn't they be better off purchasing the
"straight-wire" source, amp and speakers, and not playing with eqs to
compensate for the inferiority of "curly-wire" products?

Show me a room and speaker with "straight-wire" response and I'll try to
answer your question more directly.

If the latter then how can you quantify what is a "proper" adjustment
of an eq, beyond whatever the listener prefers?

Well that's just it - in the end everybody needs to impose their preferences
on system performance. The idiot's approach is to go to the high fi store
and spend money on what sounds good there. The wise man's approach is to get
the best, most suitable equipment one can, and then be prepared to make such
intelligent adjustements as are required in the listening room.

Every amp in one
 

"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!)

Every amp in one
 

Ian Molton wrote:



I dont see how it can be since to do so the box would need to have
knowledge of (at least) your room acoustics and speaker properties, and
(preferably) the room characteristics the 'target' speaker is used in.

(on top of that you'd need a profile for the other speaker, of course.)

The assumption for that box, is that its driving either a clean PA, or a
desk, so it only needs to take into account the sound produced by
different speakers with different mikeing methods.

Remember we are not talking HiFi speakers here, the difference in sound
(for example) between a open backed AC30 and a closed Marshal 4*12 is
know and it does a good job of duplications. I don't own one, but have
played with one for some time. Its a useful box.

--
Nick

Every amp in one
 

In article , JustMe
wrote:


What you *could* do, though is something like the following.

Play music through the Alchemist into a pair of speakers. While doing
so, connect leads to the speaker terminals and record the signals
there onto CD-R using a reasonably quality recorder. Note the signal
level with a meter.
[snip details]

I would be happy to try something like this blind. I'd be really curious
to see if such "filters" were possible and whether I would be able to
tell differences, or recognise my favourites as superior to those which
I'd previously rejected.

The snag is that even if the above allowed you to 'record' or 'reproduce'
the specific effect of a given amp, you may still need it as the 'filter'
unless we could establish what it was doing to be able to 'mimic' it in
some other way. That said, what your reactions were to such a test would be
interesting.

Presumably the playback equipment would have to be that which is
considered as "straight-line" - the CD player and amp?

Depends what you are trying to detect or establish. For example, it may be
easier to determine if you think the sounds are 'similar', but harder to
establish what it involved or what may affect the degree of 'similarity'
(if any).

But is there a danger of a cumulative effect? If I use the same speakers
in replaying the signal as it's been recorded from the system, would the
effects of the speaker's balance not be duplicated?

Not their conversion efficiency, etc. Just the effect of their input
impedance upon the signal at the speaker terminals. In effect, this is the
'break point' in the comparisons as I described them.

Would this be cumulative? Presumably, any small deviance from
"straight-line" in the CD or amp's replay would undermine such an
experiment.

It may do. However it may also turn out to be small enough not to have a
significant effect on the results.


In principle, you can perform the kinds of tests I am describing in
various ways. e.g. Do a 'speaker terminals' recording using amp 'A',
and then another using amp 'B'. Then compare the two recorded CD's
using first 'A' and then 'B' to see if you can distinguish them
in each case, and hear the effects of 'AA' 'AB' 'BA' and 'BB' if
you see what I mean.

Also, could record one channel (left or right) using 'A'. Use the
power amp input for one recorded channel, and the loudspeaker
terminal signal for the other recorded channel. Repeat this
for amp 'B'. Then replay each of the recorded 'mono' discs via
'A' and then 'B' and listen for any departures for 'mono'.

None of these tests in themselves are 'perfect' in terms of
excluding all other effects, etc. However by doing a series
of such tests you might be able to form some conclusions about
what is happening that is consistent with the comparisions they
represent.



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

The designer should design what people want. This way he gets to eat. :-)

The snag is, no-one can fully define that, and people argue about what they
want. ;- Hence you just have to make a best guess...

I personally tend to prefer amps with a fairly flat response and low
distortion. (Both terms relative to what can be expected compared with
other places in the chain. e.g speakers and room acoustics.)

Do you think that this is attainable?

I would say 'yes' with the qualifiers that:

1) Close enough to the 'Walker' definition so that any changes produced by
the chain in which the amp is a part tend to be mainly due to things like
the speakers, room acoustics, decisions made by those who made the
recording, etc. i.e. sufficiently close that departures from the 'Walker'
definition are small w.r.t. these other sources of departure from an ideal.

2) Still may not be what everyone wants. :-)


FWIW I feel that a lot of equipment comparisions (and arguments) tend
to become hung up on worries about things not being 'identical. However
in practice I think what matters is a set of slightly different levels
of comparison. e.g. Are the units 'indistingushable' in the conditions
of use? (i.e. may well differ, but in ways that are small enough to
go un-noticed). Or are any differences between two units so small that
they really don't matter much when other items in the 'chain' produce
much more noticable effects?

Also, some 'effects' may be useful in some contexts, but not others.
The obvious example is that if your speakers/room cause a change in
response at some frequencies, you might prefer an amp in the system
that counteracted this. However if so, my personal preference would
be to know this was happening so it was a conscious decision to
do this, not an 'accident' in the sense that you just find a given
system preferrable but have no idea why. Knowing the reasons gives
you the ability to make other changes which you might prefer at a
later date, and not be 'tied' to a given unit without knowing
why this is the case...

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 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

Every amp in one
 

"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?

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" :o)

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.

Every amp in one
 

JustMe wrote:

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!)

The Quad405 isnt bad. There are better.

in the valve camp other people have mentioned examples of transparent amps.

Every amp in one
 

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.

Every amp in one
 

"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.

Every amp in one
 

"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

Every amp in one
 

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

Every amp in one
 

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

Every amp in one
 

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)?

Every amp in one
 

"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.

Every amp in one
 

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

Every amp in one
 

On Fri, 19 Nov 2004 18:25:23 -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?

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" :o)

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

Every amp in one
 

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

Every amp in one
 

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

Every amp in one
 

"Alan Murphy" wrote in message

"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.

Are you socially-challenged or what, starting your discussion out with an
insult?

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.

The most serious problem with listening tests is of course, the listener.
He's merely human.

Serial tests do not reveal subtle differences.

You mean everybody here is not doing serial listening tests?

What is better?

Every amp in one
 

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

Every amp in one
 

"Stewart Pinkerton" wrote in message
...
On Fri, 19 Nov 2004 18:25:23 -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?

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" :o)

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*

Every amp in one
 

e

God made the *807*



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

Every amp in one
 

"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 )-:

Every amp in one
 

"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).
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.

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" :o)

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.

I don't have any experience with these.

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).

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?

Every amp in one
 

"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.

Every amp in one
 

"Arny Krueger" wrote in message
...
"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

Audio files of what?

Every amp in one
 

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


What you *could* do, though is something like the following.

Play music through the Alchemist into a pair of speakers. While doing
so, connect leads to the speaker terminals and record the signals
there onto CD-R using a reasonably quality recorder. Note the signal
level with a meter.
[snip details]

I would be happy to try something like this blind. I'd be really curious
to see if such "filters" were possible and whether I would be able to
tell differences, or recognise my favourites as superior to those which
I'd previously rejected.

The snag is that even if the above allowed you to 'record' or 'reproduce'
the specific effect of a given amp, you may still need it as the 'filter'
unless we could establish what it was doing to be able to 'mimic' it in
some other way. That said, what your reactions were to such a test would
be
interesting.

Presumably the playback equipment would have to be that which is
considered as "straight-line" - the CD player and amp?

Depends what you are trying to detect or establish. For example, it may be
easier to determine if you think the sounds are 'similar', but harder to
establish what it involved or what may affect the degree of 'similarity'
(if any).

But is there a danger of a cumulative effect? If I use the same speakers
in replaying the signal as it's been recorded from the system, would the
effects of the speaker's balance not be duplicated?

Not their conversion efficiency, etc. Just the effect of their input
impedance upon the signal at the speaker terminals. In effect, this is the
'break point' in the comparisons as I described them.

Would this be cumulative? Presumably, any small deviance from
"straight-line" in the CD or amp's replay would undermine such an
experiment.

It may do. However it may also turn out to be small enough not to have a
significant effect on the results.


In principle, you can perform the kinds of tests I am describing in
various ways. e.g. Do a 'speaker terminals' recording using amp 'A',
and then another using amp 'B'. Then compare the two recorded CD's
using first 'A' and then 'B' to see if you can distinguish them
in each case, and hear the effects of 'AA' 'AB' 'BA' and 'BB' if
you see what I mean.

Also, could record one channel (left or right) using 'A'. Use the
power amp input for one recorded channel, and the loudspeaker
terminal signal for the other recorded channel. Repeat this
for amp 'B'. Then replay each of the recorded 'mono' discs via
'A' and then 'B' and listen for any departures for 'mono'.

None of these tests in themselves are 'perfect' in terms of
excluding all other effects, etc. However by doing a series
of such tests you might be able to form some conclusions about
what is happening that is consistent with the comparisions they
represent.

They are also realistic options and perfectly doable with the resources I
have. I'll do this at a date in the not-too-distant future to see if I can
isolate where the difference in preference for the Kraken lies (see in the
amp's pre amp stage, or in its power amp stage - or both!)

I still want me "every-amp-in-one", though :o)

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

The designer should design what people want. This way he gets to eat. :-)

And the people get to pay for what they want, not what someone tells them
they *should* want.

The snag is, no-one can fully define that, and people argue about what
they
want. ;- Hence you just have to make a best guess...

I personally tend to prefer amps with a fairly flat response and low
distortion. (Both terms relative to what can be expected compared with
other places in the chain. e.g speakers and room acoustics.)

Do you think that this is attainable?

I would say 'yes' with the qualifiers that:

1) Close enough to the 'Walker' definition so that any changes produced by
the chain in which the amp is a part tend to be mainly due to things like
the speakers, room acoustics, decisions made by those who made the
recording, etc. i.e. sufficiently close that departures from the 'Walker'
definition are small w.r.t. these other sources of departure from an
ideal.

2) Still may not be what everyone wants. :-)

Hence the my "every-amp" solution! You build as close to "straight-line" as
you can and then release a series of plug-ins (these can be mechanical or
software for consumers) to emulate other popular designs. You'll clean up
:o)

FWIW I feel that a lot of equipment comparisions (and arguments) tend
to become hung up on worries about things not being 'identical. However
in practice I think what matters is a set of slightly different levels
of comparison. e.g. Are the units 'indistingushable' in the conditions
of use? (i.e. may well differ, but in ways that are small enough to
go un-noticed). Or are any differences between two units so small that
they really don't matter much when other items in the 'chain' produce
much more noticable effects?

This is the choice that hifi consumers make. Usually it is one based on the
difference:cost ratio. If it can be justified then the purchase is made,
otherwise it shouldn't be.

Also, some 'effects' may be useful in some contexts, but not others.
The obvious example is that if your speakers/room cause a change in
response at some frequencies, you might prefer an amp in the system
that counteracted this.

Indeed, and I have experienced this after a move before. I moved the hifi
from a large, high-ceilinged room with carpet over wooden-floorboards, to a
smaller room with carpet over concreted floor and was *very* disappointed. I
tried many different speakers and placement options to get the sound right,
but nothing helped. Finally I tried a different amp and was instantly
satisfied. The original speakers with B&W CDM7SEs, which I kept after the
move, and the amp was an AMC CVT3030a, which I swapped for the Alchemist
Forseti Pre/Power.

I also tried the 8000Q with the Forseti power, assuming it would sound
better and provide the convenience of remote control. I was *very*
disappointed again, and went back to the Forseti pre amp.

However if so, my personal preference would
be to know this was happening so it was a conscious decision to
do this, not an 'accident' in the sense that you just find a given
system preferrable but have no idea why. Knowing the reasons gives
you the ability to make other changes which you might prefer at a
later date, and not be 'tied' to a given unit without knowing
why this is the case...

I'm about to go through the same process again, probably to last me a lot
longer.

Slainte,

Jim


Many thanks!

Every amp in one
 

"Arny Krueger" wrote in message
...
"Alan Murphy" wrote in message

"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.

Are you socially-challenged or what, starting your discussion out with an
insult?

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.

The most serious problem with listening tests is of course, the listener.
He's merely human.

Serial tests do not reveal subtle differences.

You mean everybody here is not doing serial listening tests?

What is better?

Oi you two. This was a lovely peaceful thread. Take it outside :o)