[Harry Lavo]

Here is an excerpt from the April 2003 issue of "The Secrets of Home Theatre
and High Fidelity Audio" webzine. The author is John E Johnson, Jr. His
tests show conventionally excellent performance and support the 200wpc (8
ohm) and 300wpc (4 ohm) ratings with very low distortion.

"The circuit uses 6 stages. Up to 80 watts, it is Class A/B, and above 80
watts, the amplifier switches (in 2 microseconds) to Class G (digital
switching amplification). The combination of Class A/B and Class G in one
amplifier is a little out of the ordinary."

As satisfied owner of five Outlaw M200 monoblocks, I wonder why their
approach has not been used by others...or perhaps it has and I am not aware
of it. I'd also be interested in the group's perception of the issues the
approach entails.

I use the monoblocks to drive five full-range Thiel speakers (two L/R 2 2's;
three C/LS/RS 3.5's). The combination is teriffic: total stability,
effortless dynamics, and teriffic micro-dynamics and transparency for the
price point (~$300 per channel).

My only other experience with a digital switching amp is the Onkyo M501,
which has a horrible high-end. I've also heard bad things via hearsay wrt
other digital switching full-range amps. The Outlaw stays absolutely
"sweet" at all volumes, and with no sonic discontinuties anywhere within its
audible range. The only noticeable flaw is a slightly soft high end, which
can be offset by about a 1db boost at 15khz using my preamp tone controls.

Anybody have experience with this amp? With others? Comments or
observations about "Class G" switching.

[Arny Krueger]

"Harry Lavo" wrote in message


Here is an excerpt from the April 2003 issue of "The
Secrets of Home Theatre and High Fidelity Audio" webzine.
The author is John E Johnson, Jr. His tests show
conventionally excellent performance and support the
200wpc (8 ohm) and 300wpc (4 ohm) ratings with very low
distortion.
"The circuit uses 6 stages. Up to 80 watts, it is Class
A/B, and above 80 watts, the amplifier switches (in 2
microseconds) to Class G (digital switching
amplification). The combination of Class A/B and Class G
in one amplifier is a little out of the ordinary."


The parenthetical comment above which in larger context says "...the
amplifier switches (in 2
microseconds) to Class G (digital switching amplification)." is one of
those comments that brings the reveiwer's technical skills into question.
No way is Class G digital switching amplification. Class G operation
involves switching the voltage of the output stage power supply voltage.

BTW, readers familiar with the www.pcavtech.com web site might recognize the
source of the test results as coming from one of the Spectra series of
PC-based signal analysers.

The review pulls some punches, testing HF IM at the relatively low
frequencies of 10 and 11 KHz, and not testing IM at the higher 40 volt
levels they use for other tests. There is no testing with simulated speaker
load, and there is no testing at really low operating levels such as 1 watt.

Here's an example of my idea of a comprehensive set of power amp tests:

http://www.pcavtech.com/pwramp/macrot-5000VZ/index.htm

[Trevor Wilson]

"Harry Lavo" wrote in message
. ..
Here is an excerpt from the April 2003 issue of "The Secrets of Home
Theatre and High Fidelity Audio" webzine. The author is John E Johnson,
Jr. His tests show conventionally excellent performance and support the
200wpc (8 ohm) and 300wpc (4 ohm) ratings with very low distortion.

"The circuit uses 6 stages. Up to 80 watts, it is Class A/B, and above 80
watts, the amplifier switches (in 2 microseconds) to Class G (digital
switching amplification). The combination of Class A/B and Class G in one
amplifier is a little out of the ordinary."

**Class G is not switching amplification. Class G is another variant on a
'rail switcher'. It's been done many times in the past, by many
manufacturers. The results vary from reasonable to horrible. My personal
feeling is that there are really only fours classes of audio amplification.
Class A, Class B, Class A/B and Class D. ALl the other classes (except Class
C) are just bull****. They are really only power supply variations. The
fundamental amplifier class is determined by the bias current (Class A, A/B
and B), whilst Class D is fundamentally different.



As satisfied owner of five Outlaw M200 monoblocks, I wonder why their
approach has not been used by others...or perhaps it has and I am not
aware of it. I'd also be interested in the group's perception of the
issues the approach entails.

**Like I said, It has been done before, with variable success rates. In
reality, however, the BEST amplification is still high bias Class A/B, with
no dodgy power supply rail switching schemes. Such schemes are really only
ways to cut costs. They're not a technologically superior method of doing
anything. IOW: More power for less money.


I use the monoblocks to drive five full-range Thiel speakers (two L/R 2
2's; three C/LS/RS 3.5's). The combination is teriffic: total stability,
effortless dynamics, and teriffic micro-dynamics and transparency for the
price point (~$300 per channel).

**Yadda, yaddda, yadda. Compare your amps to some really good, non-rail
switched amps, in a blind trial, then get back to us.


My only other experience with a digital switching amp is the Onkyo M501,
which has a horrible high-end. I've also heard bad things via hearsay wrt
other digital switching full-range amps. The Outlaw stays absolutely
"sweet" at all volumes, and with no sonic discontinuties anywhere within
its audible range. The only noticeable flaw is a slightly soft high end,
which can be offset by about a 1db boost at 15khz using my preamp tone
controls.

**Measured how? Tone controls are worse than useless, in the hands of
novices. Particularly if those novices have no references, nor proper test
equipment.


Anybody have experience with this amp? With others? Comments or
observations about "Class G" switching.

**It's cheap.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[Harry Lavo]

"Trevor Wilson" wrote in message
...

"Harry Lavo" wrote in message
. ..
Here is an excerpt from the April 2003 issue of "The Secrets of Home
Theatre and High Fidelity Audio" webzine. The author is John E Johnson,
Jr. His tests show conventionally excellent performance and support the
200wpc (8 ohm) and 300wpc (4 ohm) ratings with very low distortion.

"The circuit uses 6 stages. Up to 80 watts, it is Class A/B, and above 80
watts, the amplifier switches (in 2 microseconds) to Class G (digital
switching amplification). The combination of Class A/B and Class G in one
amplifier is a little out of the ordinary."

**Class G is not switching amplification. Class G is another variant on a
'rail switcher'. It's been done many times in the past, by many
manufacturers. The results vary from reasonable to horrible. My personal
feeling is that there are really only fours classes of audio
amplification. Class A, Class B, Class A/B and Class D. ALl the other
classes (except Class C) are just bull****. They are really only power
supply variations. The fundamental amplifier class is determined by the
bias current (Class A, A/B and B), whilst Class D is fundamentally
different.

You are not the first to point this out; obviously, then, the reviewer was
wrong.




As satisfied owner of five Outlaw M200 monoblocks, I wonder why their
approach has not been used by others...or perhaps it has and I am not
aware of it. I'd also be interested in the group's perception of the
issues the approach entails.

**Like I said, It has been done before, with variable success rates. In
reality, however, the BEST amplification is still high bias Class A/B,
with no dodgy power supply rail switching schemes. Such schemes are really
only ways to cut costs. They're not a technologically superior method of
doing anything. IOW: More power for less money.

In this case less money perhaps but also less heat and less size. These are
marvelous little pancake units with great ventilation and no fans. But
despite a large toroidal PS (they weight 18 lbs each) they do not get hot.
Their advantage in a multichannel system, besides rack flexibiity, is that
they can be triggered by an active signal (as well as by a 12v trigger
current) so essentially when the system is in 2-channel mode, the other
three channels turn off, drawing only 3 watts each in standby.




I use the monoblocks to drive five full-range Thiel speakers (two L/R 2
2's; three C/LS/RS 3.5's). The combination is teriffic: total stability,
effortless dynamics, and teriffic micro-dynamics and transparency for the
price point (~$300 per channel).

**Yadda, yaddda, yadda. Compare your amps to some really good, non-rail
switched amps, in a blind trial, then get back to us.

Well, to an ARC D90B, a VTL ST-85, a CJ 2500, and an Audionics CC-2 they
stand up extremely well. Seem to be about on par with my brother-in-law's
Krell 300....perphaps a shade smoother and a tad less transparent.



My only other experience with a digital switching amp is the Onkyo M501,
which has a horrible high-end. I've also heard bad things via hearsay
wrt other digital switching full-range amps. The Outlaw stays absolutely
"sweet" at all volumes, and with no sonic discontinuties anywhere within
its audible range. The only noticeable flaw is a slightly soft high
end, which can be offset by about a 1db boost at 15khz using my preamp
tone controls.

**Measured how? Tone controls are worse than useless, in the hands of
novices. Particularly if those novices have no references, nor proper test
equipment.

As an audiophile for 45 years, I'm not a novice. In the second place, I
normally bypass tone controls but my current preamps have them. In the
third place, I know how to use a voltmeter and have an audio frequency
generator. So the 1 db is approximately correct based on some testing I did
a few years ago.

Anybody have experience with this amp? With others? Comments or
observations about "Class G" switching.

**It's cheap.


I'd call it more mid-priced than cheap. But at roughly $300 per unit it is
certainly not ultra-expensive. I like it as well/better than any solid
state amp I have heard that sells for $600 per channel or less.

[Eeyore]

Harry Lavo wrote:

Here is an excerpt from the April 2003 issue of "The Secrets of Home Theatre
and High Fidelity Audio" webzine. The author is John E Johnson, Jr. His
tests show conventionally excellent performance and support the 200wpc (8
ohm) and 300wpc (4 ohm) ratings with very low distortion.

"The circuit uses 6 stages. Up to 80 watts, it is Class A/B, and above 80
watts, the amplifier switches (in 2 microseconds) to Class G (digital
switching amplification). The combination of Class A/B and Class G in one
amplifier is a little out of the ordinary."

********.

I've designed them myself. And some Class H too.

Nothing new there at all.

Graham

[Eeyore]

Stuart Krivis wrote:

Given a conventional linear amp vs. a "Class G" amp like this, it
would seem logical to assume that the conventional amp will perform
better since it isn't doing any power supply (or output device as
Outlaw seems to say) switching.

At low powers it *does* function as a conventional amp.


The only reasons for going with Class G would not then involve how it
sounds. Class G might be less expensive, it might be smaller, it might
weigh less, and it might produce less heat or use less power.

It's used for PA / SR amps to reduce output stage dissipation.

That's it. It's not suitable for 'audiophile' use since there is an inevitable
breakthrough from the switched supply rail to the output.

Graham

[Eeyore]

Trevor Wilson wrote:

**Class G is not switching amplification. Class G is another variant on a
'rail switcher'. It's been done many times in the past, by many
manufacturers. The results vary from reasonable to horrible.

Oi !

I've designed a really damn good one ! I wouldn't recommend it for audiophile
use though.

Graham

[Eeyore]

Trevor Wilson wrote:


**Like I said, It has been done before, with variable success rates. In
reality, however, the BEST amplification is still high bias Class A/B, with
no dodgy power supply rail switching schemes. Such schemes are really only
ways to cut costs.

It's done to cut down dissipation primarily. In high power amplifiers this
eventually become a very significant issue and might otherwise require
impossibly large heatsinks. It's an excellent way of improving efficiency.

Graham

[Eeyore]

Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Graham

[Eeyore]

Harry Lavo wrote:

As an audiophile for 45 years, I'm not a novice.

!!!!!

Pull the other one.


Graham

[Arny Krueger]

"Stuart Krivis" wrote in message


Given a conventional linear amp vs. a "Class G" amp like
this, it would seem logical to assume that the
conventional amp will perform better since it isn't doing
any power supply (or output device as Outlaw seems to
say) switching.

The power supply switching can cause problems, or not. It's a matter of
design refinement.

Looking at the review that Harry was not capable of providing a proper link
to:

http://www.hometheaterhifi.com/volum...er-4-2003.html

There seems to be excessive degradation of performance when the amp switches
into high power mode.

I would expect the performance at 5 volts into 8 ohms to be more like the
performance at 40 volts into 8 ohms unless the amp were on the verge of
clipping at the higher power level. There would be some increase in
distortion, but not so much.

If the amp were on the as far into clipping at 1 KHz and 40 volts into 8
ohms at it may seem, then the power amp might not be very conservatively
rated.

The data is fragmentary, and not too much should be interpolated from it, I
guess.

The data also seems to be based on an unusual approach - the data
superfically appears to be taken with the analytical equipment running up to
45 dB below full scale. On further investigation, I doubt that the data is
what it seems at first blush.

[Harry Lavo]

"Eeyore" wrote in message
...


Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Graham


No offense taken :-)

I should have said "only gets mildly warm". The configuration is
essentially a pancake with a fairly large proportion of the top and bottom
covers as grillwork, and this along with their design seems to keep heat
levels very, very modest.

[Eeyore]

Harry Lavo wrote:

"Eeyore" wrote in message
Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Graham

No offense taken :-)

I should have said "only gets mildly warm". The configuration is
essentially a pancake with a fairly large proportion of the top and bottom
covers as grillwork, and this along with their design seems to keep heat
levels very, very modest.

That suggests it was well heatsunk originally.

Typical Class H operation can halve output device dissipation.

Graham

[Bertie the Bunyip]

Eeyore wrote in
:



Harry Lavo wrote:

"Eeyore" wrote in message
Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Graham

No offense taken :-)

I should have said "only gets mildly warm". The configuration is
essentially a pancake with a fairly large proportion of the top and
bottom covers as grillwork, and this along with their design seems to
keep heat levels very, very modest.

That suggests it was well heatsunk originally.

Typical Class H operation can halve output device dissipation.


Aww.


Bertie

[Bertie the Bunyip]

Eeyore wrote in
:



Harry Lavo wrote:

As an audiophile for 45 years, I'm not a novice.

!!!!!

Pull the other one.



Nah, too easy



Bertie

[Bertie the Bunyip]

Eeyore wrote in
:



Stuart Krivis wrote:

Given a conventional linear amp vs. a "Class G" amp like this, it
would seem logical to assume that the conventional amp will perform
better since it isn't doing any power supply (or output device as
Outlaw seems to say) switching.

At low powers it *does* function as a conventional amp.


The only reasons for going with Class G would not then involve how it
sounds. Class G might be less expensive, it might be smaller, it
might weigh less, and it might produce less heat or use less power.

It's used for PA / SR amps to reduce output stage dissipation.

That's it. It's not suitable for 'audiophile' use since there is an
inevitable breakthrough from the switched supply rail to the output.



luser boi



bertei

[Bertie the Bunyip]

Eeyore wrote in
:



Trevor Wilson wrote:

**Class G is not switching amplification. Class G is another variant
on a 'rail switcher'. It's been done many times in the past, by many
manufacturers. The results vary from reasonable to horrible.

Oi !

I've designed a really damn good one ! I wouldn't recommend it for
audiophile use though.



Wannabe luser boi....



Bertie

[Bertie the Bunyip]

Eeyore wrote in
:



Trevor Wilson wrote:


**Like I said, It has been done before, with variable success rates.
In reality, however, the BEST amplification is still high bias Class
A/B, with no dodgy power supply rail switching schemes. Such schemes
are really only ways to cut costs.

It's done to cut down dissipation primarily. In high power amplifiers
this eventually become a very significant issue and might otherwise
require impossibly large heatsinks. It's an excellent way of improving
efficiency.

Graham


netkkkkopin ggarbage




Bertie

[Bertie the Bunyip]

Eeyore wrote in
:



Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Graham

Luser wannabe



Bertie

[Randy Yates]

Eeyore writes:

Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Bull****. The more efficient an amplifier is, the
less heat it dissipates. Class D/H are known to be
very efficient.
--
% Randy Yates % "So now it's getting late,
%% Fuquay-Varina, NC % and those who hesitate
%%% 919-577-9882 % got no one..."
%%%% % 'Waterfall', *Face The Music*, ELO
http://home.earthlink.net/~yatescr

[Eeyore]

Randy Yates wrote:

Eeyore writes:
Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Bull****. The more efficient an amplifier is, the
less heat it dissipates. Class D/H are known to be
very efficient.

Class H is barely twice as efficient as Class AB. They definitely 'get
hot'.

Even Class D amps have conduction and switching losses.

Graham

[Mr.T]

"Arny Krueger" wrote in message
...
The data also seems to be based on an unusual approach - the data
superfically appears to be taken with the analytical equipment running up
to
45 dB below full scale. On further investigation, I doubt that the data
is
what it seems at first blush.

Your being far too generous Arny. What is quite apparent is that he has no
idea of proper testing methodology.

MrT.

[Bertie the Bunyip]

Eeyore wrote in
:



Randy Yates wrote:

Eeyore writes:
Harry Lavo wrote:

they do not get hot.

All amplifiers 'get hot' you clown !

Even Class-D ones.

Bull****. The more efficient an amplifier is, the
less heat it dissipates. Class D/H are known to be
very efficient.

Class H is barely twice as efficient as Class AB. They definitely 'get
hot'.

Even Class D amps have conduction and switching losses.

Graham



netttkkkppn gfjukkwit




Bertie