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Book Review: High-Power Audio Amplifier Construction Manual

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Anonymous
May 9, 2004 9:01:20 PM

Archived from groups: rec.audio.tech (More info?)

A large poor book written around a small fair one

High-Power Audio Amplifier Construction Manual; G.Randy Slone

As a DIY guide for building class-B solid state audio power amps, this
book has some merit. However, the author takes a great deal of space
to attack the high-end audio business, denigrate vacuum tubes, and
denounce "audio subjectivism". There are those who will consider these
worthy goals, but even they wil be disappointed in his eighth-grade
forensics as he sets up strawmen with little facility.

His foreword clearly brings to mind William Burroughs' famous comment
on which people, should one elect to do business with them, you should
get any statements they make in writing!

If for some reason you want to etch circuit boards and fabricate
heatsink assemblies to build a type of amp you can buy from Crown or
Peavey for less than the parts would cost a hobbyist, Slone's book is
somewhat useful. His presentation of the theory is less comprehensible
than that of Douglas Self, and assumes a reasonable amount of
solid-state theory and the basics of feedback and stability, which
many project-oriented hobbyists will lack.

However, there are numerous better works on the theory and practice of
solid-state amplification,should one wish to repair them or actually
design one, and any discussion of the respective merits of solid-state
versus tube amplifiers in audio service still starts with Russell O.
Hamm's definitive JAES paper, "Tubes versus Transistors: Is There a
Difference?". It's interesting that Slone does not cite or acknowledge
this document anywhere in this book, or in any other.

It's worth noting that although there are many solid state amp designs
hobby builders have constructed with excellent sonic reviews-published
designs by Nelson Pass and Norman Thagard as well as clones of Quad
and Krell commercial amps-probably twenty times as many tube
amplifiers as solid-state are constructed by American hobby builders
each year. I have built both and had success with both, and
surprisingly, having started in hobby construction as a hard-core tube
obsessive, I now think solid state has the edge. Slone's book,
ultimately, does the case of solid state little good. Tube amplifiers
are easier to build for most hobbyists, easier to fix, and their sonic
flaws are invariably more euphonic than those of solid state
amplifiers: solid state takes a lot more discipline to get right. By
denying these obvious facts, Slone puts tube buffs in an even more
confrontational position, which does no one any good.


Was this review helpful to you?
Anonymous
May 10, 2004 1:55:34 AM

Archived from groups: rec.audio.tech (More info?)

Fred Collins wrote:

> ...any discussion of the respective merits of solid-state
> versus tube amplifiers in audio service still starts with Russell O.
> Hamm's definitive JAES paper, "Tubes versus Transistors: Is There a
> Difference?".

Not at all. To quote Hamm's JAES paper's abstract:

"This paper, however, points out that amplifiers are often severely
overloaded by signal transients (THD 30%). Under this condition there is a
major difference in the harmonic distortion components of the amplified
signal, with tubes, transistors, and operational amplifiers separating into
distinct groups"

Thus the Hamm 1973 paper is only relevant to people who judge amplifiers by
how they sound when grossly abused. It is therefore irrelevant to those of
us who use hi fi amplifiers reasonably and sanely.

>It's interesting that Slone does not cite or acknowledge this document
anywhere in this book, or in any other.

That's because Hamm's JAES paper, according to its own abstract, is
irrelevant to the use of audio amplifiers as Hi Fi components.

It should be pointed out that the form of the Hamm paper that seems to be
most commonly posted on the web is not the 1973 JAES paper, but the longer
1972 conference paper.
Anonymous
May 11, 2004 12:01:25 AM

Archived from groups: rec.audio.tech (More info?)

Disagree entirely.

I read the book and thoroughly enjoyed it - I found Randy's writing
style very enjoyable; he pulls no punches and says what he thinks,
backed up, I felt, with justified opinions. Obviously, these are not the
opinions you hold!

I found his explanations of "tube" electronics very helpful - he cleared
up a number of misunderstandings in my mind and helped me to understand
some of the subjectivism in this hobby.

If you're interested in learning how to build solid-state amps, this is
a great book. I am a little confused with your comment that amps can be
bought for cheaper than the kits described in Slone's book (assuming the
same sonic quality) - this is in direct contradiction to Slone's
assertions.

I'd love to know where you get your facts regarding the number of tube
amps versus solid-state amps built in the US - source please?

My bottom line - a great book, well worth the read. I plan to try my
hand at a couple of his designs.

Regards,

Adam Drake.


Fred Collins wrote:
> A large poor book written around a small fair one
>
> High-Power Audio Amplifier Construction Manual; G.Randy Slone
>
> As a DIY guide for building class-B solid state audio power amps, this
> book has some merit. However, the author takes a great deal of space
> to attack the high-end audio business, denigrate vacuum tubes, and
> denounce "audio subjectivism". There are those who will consider these
> worthy goals, but even they wil be disappointed in his eighth-grade
> forensics as he sets up strawmen with little facility.
>
> His foreword clearly brings to mind William Burroughs' famous comment
> on which people, should one elect to do business with them, you should
> get any statements they make in writing!
>
> If for some reason you want to etch circuit boards and fabricate
> heatsink assemblies to build a type of amp you can buy from Crown or
> Peavey for less than the parts would cost a hobbyist, Slone's book is
> somewhat useful. His presentation of the theory is less comprehensible
> than that of Douglas Self, and assumes a reasonable amount of
> solid-state theory and the basics of feedback and stability, which
> many project-oriented hobbyists will lack.
>
> However, there are numerous better works on the theory and practice of
> solid-state amplification,should one wish to repair them or actually
> design one, and any discussion of the respective merits of solid-state
> versus tube amplifiers in audio service still starts with Russell O.
> Hamm's definitive JAES paper, "Tubes versus Transistors: Is There a
> Difference?". It's interesting that Slone does not cite or acknowledge
> this document anywhere in this book, or in any other.
>
> It's worth noting that although there are many solid state amp designs
> hobby builders have constructed with excellent sonic reviews-published
> designs by Nelson Pass and Norman Thagard as well as clones of Quad
> and Krell commercial amps-probably twenty times as many tube
> amplifiers as solid-state are constructed by American hobby builders
> each year. I have built both and had success with both, and
> surprisingly, having started in hobby construction as a hard-core tube
> obsessive, I now think solid state has the edge. Slone's book,
> ultimately, does the case of solid state little good. Tube amplifiers
> are easier to build for most hobbyists, easier to fix, and their sonic
> flaws are invariably more euphonic than those of solid state
> amplifiers: solid state takes a lot more discipline to get right. By
> denying these obvious facts, Slone puts tube buffs in an even more
> confrontational position, which does no one any good.
>
>
> Was this review helpful to you?
Related resources
Anonymous
May 11, 2004 1:16:06 AM

Archived from groups: rec.audio.tech (More info?)

He makes a number of flat out wrong statements, such as that no
recording studios use tube amps for monitoring and mixdown, and
concantenates issues by saying that "monoblock" amplifiers are not
superior in stereo separation because "single-ended, directly heated
triode" amps are available which produce up to 5% THD. "Monoblock"
simply means a single channel amplifier: whether it's a tube or solid
state amp, or whether it is single-ended or push-pull, or whether it
uses triodes or beam power tetrodes are all separate issues. (The most
expensive of all single-ended amplifiers is in fact a stereo
integrated amp.)

Of course, he fails to bring up any concept not in line with his
doctrine, such as the idea that for hi-fi use the behavior of an
amplifier at very low signal levels is most important-the "first watt"
theory- or the idea tha Class AB amplifiers operate in Class A for the
lower portion of their power band. These are not relevant concepts for
PA or MI use but for domestic listening they are why amplifier designs
have evolved as they have.

Mr. Krueger's statement that he does not abuse his amplifers in
domestic listening may mean that he listens exclusively to
limited-dynamic-range music or that he does in fact have 10 kW of
amplifier power in his living room. As McIntosh literature trumpeted
all through the eighties, given reasonable room sizes in more affluent
American's homes, the inefficient speakers in popular use then (and
now), and a desire to listen to orchestral music with the quietest
portions clearly audible over an average residential noise floor-you
need about 10 kW so as to never clip an amplifier. Alternatively, a
pair of Teletronix limiters will keep things in order, anathema though
this may be, most people didn't really want to hear those cannon shots
all that loud anyway...
Anonymous
May 11, 2004 9:51:39 AM

Archived from groups: rec.audio.tech (More info?)

"Fred Collins" <fredcollins7r@hotmail.com> wrote in message
news:55e592e9.0405102016.6ff9f100@posting.google.com...

<snip>

> Mr. Krueger's statement that he does not abuse his amplifers in
> domestic listening may mean that he listens exclusively to
> limited-dynamic-range music or that he does in fact have 10 kW of
> amplifier power in his living room. As McIntosh literature trumpeted
> all through the eighties, given reasonable room sizes in more affluent
> American's homes, the inefficient speakers in popular use then (and
> now), and a desire to listen to orchestral music with the quietest
> portions clearly audible over an average residential noise floor-you
> need about 10 kW so as to never clip an amplifier. Alternatively, a
> pair of Teletronix limiters will keep things in order, anathema though
> this may be, most people didn't really want to hear those cannon shots
> all that loud anyway...

I'd have to disagree with you here. Playing a full-scale tone from a test
CD, my 100 watt/channel stereo amplifier clips when the volume is set to the
12:00 position (1/2 way up). I *never* run my amplifier anywhere near that
high with any normal program material -- it would be far too loud. With the
volume set to less than 1/2, my amplifier couldn't possibly be clipping with
any kind of program material.
Anonymous
May 11, 2004 10:06:38 AM

Archived from groups: rec.audio.tech (More info?)

Fred Collins wrote:

> He makes a number of flat out wrong statements, such as that no
> recording studios use tube amps for monitoring and mixdown, and
> concantenates issues by saying that "monoblock" amplifiers are not
> superior in stereo separation because "single-ended, directly heated
> triode" amps are available which produce up to 5% THD. "Monoblock"
> simply means a single channel amplifier: whether it's a tube or solid
> state amp, or whether it is single-ended or push-pull, or whether it
> uses triodes or beam power tetrodes are all separate issues. (The most
> expensive of all single-ended amplifiers is in fact a stereo
> integrated amp.)

Anybody who thinks they need monoblock amplifiers in order to have adequate
separation is quite thorougly mislead.

> Of course, he fails to bring up any concept not in line with his
> doctrine, such as the idea that for hi-fi use the behavior of an
> amplifier at very low signal levels is most important-the "first watt"
> theory -

Now, that I can agree with. However, what action does that important
requirement lead us to?

> or the idea tha Class AB amplifiers operate in Class A for the
> lower portion of their power band.

I can agree with that as well. However, what action does this important fact
lead us to?

> These are not relevant concepts for
> PA or MI use but for domestic listening they are why amplifier designs
> have evolved as they have.

That's total nonsense. Quality SR and MI applications benefit from quality
audio gear as much as anything else. The SR system that I ride herd on most
frequently is based on two very large high-efficiency speakers with massive
waveguides and highly-efficent compression drivers. We drive them with a 50
wpc power amp which is probably overkill. "The first watt" is obviously very
important to their effective implementation.

> Mr. Krueger's statement that he does not abuse his amplifers in
> domestic listening may mean that he listens exclusively to
> limited-dynamic-range music or that he does in fact have 10 kW of
> amplifier power in his living room.

This would be a non-fact. Letsee, 1 125 wpc amp, and 2 75 wpc amps.That's
550 watts. Seems like you're off by a factor of nearly 20, Fred. Is the rest
of your post this factual?

>As McIntosh literature trumpeted
> all through the eighties, given reasonable room sizes in more affluent
> American's homes, the inefficient speakers in popular use then (and
> now), and a desire to listen to orchestral music with the quietest
> portions clearly audible over an average residential noise floor-you
> need about 10 kW so as to never clip an amplifier.

Exploiting 10 KW amps with home audio type speakers would lead to serious
problems with ear damage not to mention loudspeaker damage. I do know of a
couple of people with 3 KW amps, but they use them to drive
highly-inefficient subwoofers. Run the numbers - 90 dB/W speakers and 10 KW
(40 dBW) leads to SPLs in the 120-130 dB range. OSHA would not approve and
neither would any conscientious audiophile.

>Alternatively, a
> pair of Teletronix limiters will keep things in order, anathema though
> this may be, most people didn't really want to hear those cannon shots
> all that loud anyway...

Thanks for deconstructing your own ludicrous argument, Fred.
Anonymous
May 11, 2004 10:08:01 AM

Archived from groups: rec.audio.tech (More info?)

Karl Uppiano wrote:
> "Fred Collins" <fredcollins7r@hotmail.com> wrote in message
> news:55e592e9.0405102016.6ff9f100@posting.google.com...
>
> <snip>
>
>> Mr. Krueger's statement that he does not abuse his amplifers in
>> domestic listening may mean that he listens exclusively to
>> limited-dynamic-range music or that he does in fact have 10 kW of
>> amplifier power in his living room. As McIntosh literature trumpeted
>> all through the eighties, given reasonable room sizes in more
>> affluent American's homes, the inefficient speakers in popular use
>> then (and now), and a desire to listen to orchestral music with the
>> quietest portions clearly audible over an average residential noise
>> floor-you need about 10 kW so as to never clip an amplifier.
>> Alternatively, a pair of Teletronix limiters will keep things in
>> order, anathema though this may be, most people didn't really want
>> to hear those cannon shots all that loud anyway...
>
> I'd have to disagree with you here. Playing a full-scale tone from a
> test CD, my 100 watt/channel stereo amplifier clips when the volume
> is set to the 12:00 position (1/2 way up). I *never* run my amplifier
> anywhere near that high with any normal program material -- it would
> be far too loud. With the volume set to less than 1/2, my amplifier
> couldn't possibly be clipping with any kind of program material.

Unfortunately this argument has problems of its own. There is very little
that can be reliably determined from casual observation of volume control
settings. The right thing to do is to measure the waveforms at the power
amplifier output terminals.
Anonymous
May 11, 2004 10:09:12 AM

Archived from groups: rec.audio.tech (More info?)

On 10 May 2004 21:16:06 -0700, fredcollins7r@hotmail.com (Fred
Collins) wrote:

>He makes a number of flat out wrong statements, such as that no
>recording studios use tube amps for monitoring and mixdown,

True, but you are talking of perhaps four or five oddballs out of
several hundred (if not thousand) serious commercial studios, so it's
not an unreasonable comment.

>and
>concantenates issues by saying that "monoblock" amplifiers are not
>superior in stereo separation because "single-ended, directly heated
>triode" amps are available which produce up to 5% THD. "Monoblock"
>simply means a single channel amplifier: whether it's a tube or solid
>state amp, or whether it is single-ended or push-pull, or whether it
>uses triodes or beam power tetrodes are all separate issues. (The most
>expensive of all single-ended amplifiers is in fact a stereo
>integrated amp.)

Are you thinking of the Audio Note Ongaku? If so, then you are flat
out wrong, as the Gaku-On is vastly more expensive, and is a pair of
monobloc power amps. The AN Kassai Silver is also vastly more
expensive than the Ongaku, and is essentially two monobloc power amps
on a single chassis, but using the 300B rather than the 211.

> Of course, he fails to bring up any concept not in line with his
>doctrine, such as the idea that for hi-fi use the behavior of an
>amplifier at very low signal levels is most important-the "first watt"
>theory- or the idea tha Class AB amplifiers operate in Class A for the
>lower portion of their power band. These are not relevant concepts for
>PA or MI use but for domestic listening they are why amplifier designs
>have evolved as they have.

Actually, there is no such thing as a pure class B audio amplifier,
they are *all* at least slightly class AB. Also, there is nothing
'magical' about a class A design in comparison with a well-crafted
class AB or indeed class D design - they can *all* be sonically
transparent - and hence sonically identical. So-called 'high end' amp
designs have evolved as they have for various reasons which have
nothing at all to do with fidelity to the input signal..........

> Mr. Krueger's statement that he does not abuse his amplifers in
>domestic listening may mean that he listens exclusively to
>limited-dynamic-range music or that he does in fact have 10 kW of
>amplifier power in his living room.

Or it may mean that he uses medium power amps in conjunction with
reasonably sensitive speakers. Speaker sensitivity is *vastly* more
important than amplifier power, when it comes to generating lifelike
dynamic range.

>As McIntosh literature trumpeted
>all through the eighties, given reasonable room sizes in more affluent
>American's homes, the inefficient speakers in popular use then (and
>now), and a desire to listen to orchestral music with the quietest
>portions clearly audible over an average residential noise floor-you
>need about 10 kW so as to never clip an amplifier. Alternatively, a
>pair of Teletronix limiters will keep things in order, anathema though
>this may be, most people didn't really want to hear those cannon shots
>all that loud anyway...

Luckily, we have advanced somewhat on the AR-3! BTW, the noise floor
in my room is well below 30dBA, my system can peak at about 115dB at
the listening position, and there are *no* known musical master tapes
with a dynamic range exceeding 80dB - so I think I'm reasonably safe
in assuming that I can achieve realistic dynamic range in my listening
room.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
May 11, 2004 10:13:31 PM

Archived from groups: rec.audio.tech (More info?)

Adam Drake <ja_drakeNOSPAM@yahoo.com> wrote in message news:<dMadnd3jkqjPij3dRVn-sA@golden.net>...
> Disagree entirely.
>
> I read the book and thoroughly enjoyed it - I found Randy's writing
> style very enjoyable; he pulls no punches and says what he thinks,
> backed up, I felt, with justified opinions. Obviously, these are not the
> opinions you hold!
>
> I found his explanations of "tube" electronics very helpful - he cleared
> up a number of misunderstandings in my mind and helped me to understand
> some of the subjectivism in this hobby.
>
> If you're interested in learning how to build solid-state amps, this is
> a great book. I am a little confused with your comment that amps can be
> bought for cheaper than the kits described in Slone's book (assuming the
> same sonic quality) - this is in direct contradiction to Slone's
> assertions.
>
> I'd love to know where you get your facts regarding the number of tube
> amps versus solid-state amps built in the US - source please?
>
> My bottom line - a great book, well worth the read. I plan to try my
> hand at a couple of his designs.
>
> Regards,
>
> Adam Drake.
>
>
> Fred Collins wrote:
> > A large poor book written around a small fair one
> >
> > High-Power Audio Amplifier Construction Manual; G.Randy Slone
> >
> > As a DIY guide for building class-B solid state audio power amps, this
> > book has some merit. However, the author takes a great deal of space
> > to attack the high-end audio business, denigrate vacuum tubes, and
> > denounce "audio subjectivism". There are those who will consider these
> > worthy goals, but even they wil be disappointed in his eighth-grade
> > forensics as he sets up strawmen with little facility.
> >
> > His foreword clearly brings to mind William Burroughs' famous comment
> > on which people, should one elect to do business with them, you should
> > get any statements they make in writing!
> >
> > If for some reason you want to etch circuit boards and fabricate
> > heatsink assemblies to build a type of amp you can buy from Crown or
> > Peavey for less than the parts would cost a hobbyist, Slone's book is
> > somewhat useful. His presentation of the theory is less comprehensible
> > than that of Douglas Self, and assumes a reasonable amount of
> > solid-state theory and the basics of feedback and stability, which
> > many project-oriented hobbyists will lack.
> >
> > However, there are numerous better works on the theory and practice of
> > solid-state amplification,should one wish to repair them or actually
> > design one, and any discussion of the respective merits of solid-state
> > versus tube amplifiers in audio service still starts with Russell O.
> > Hamm's definitive JAES paper, "Tubes versus Transistors: Is There a
> > Difference?". It's interesting that Slone does not cite or acknowledge
> > this document anywhere in this book, or in any other.
> >
> > It's worth noting that although there are many solid state amp designs
> > hobby builders have constructed with excellent sonic reviews-published
> > designs by Nelson Pass and Norman Thagard as well as clones of Quad
> > and Krell commercial amps-probably twenty times as many tube
> > amplifiers as solid-state are constructed by American hobby builders
> > each year. I have built both and had success with both, and
> > surprisingly, having started in hobby construction as a hard-core tube
> > obsessive, I now think solid state has the edge. Slone's book,
> > ultimately, does the case of solid state little good. Tube amplifiers
> > are easier to build for most hobbyists, easier to fix, and their sonic
> > flaws are invariably more euphonic than those of solid state
> > amplifiers: solid state takes a lot more discipline to get right. By
> > denying these obvious facts, Slone puts tube buffs in an even more
> > confrontational position, which does no one any good.
> >
> >
> > Was this review helpful to you?

I must say I certainly am impressed with the debate included in this
thread.
I enjoyed reading it. I have Mr Sloans book and here is one point I
wish to
toss up for debate pg 33 #7 " Speaker cables seem to be in the
audiophile limelight these days. A good speaker cable should be
reasonbly rugged and capable of conducting the highest possible
speaker current with negligible resistive loss. Other than these two
factors, I find little else to discuss about speake cables ". Is this
accurate , I have seen some pretty impressive data on cables,the most
recent in the latest issue of Audioxpress.



Jeff
Anonymous
May 12, 2004 3:41:07 AM

Archived from groups: rec.audio.tech (More info?)

"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:_bidnTTyE6GeOz3dRVn-tA@comcast.com...
> Karl Uppiano wrote:
> > "Fred Collins" <fredcollins7r@hotmail.com> wrote in message
> > news:55e592e9.0405102016.6ff9f100@posting.google.com...
> > I'd have to disagree with you here. Playing a full-scale tone from a
> > test CD, my 100 watt/channel stereo amplifier clips when the volume
> > is set to the 12:00 position (1/2 way up). I *never* run my amplifier
> > anywhere near that high with any normal program material -- it would
> > be far too loud. With the volume set to less than 1/2, my amplifier
> > couldn't possibly be clipping with any kind of program material.
>
> Unfortunately this argument has problems of its own. There is very little
> that can be reliably determined from casual observation of volume control
> settings. The right thing to do is to measure the waveforms at the power
> amplifier output terminals.

Which I assume he has done, to be able to state it does not clip with a full
scale tone at 1/2 volume control rotation!

If we assume the CD player has a fixed output for a DFS signal, and the
amplifier has a reasonably constant gain at a given attenuator (volume
control) setting, then indeed we can say that if the amplifier can handle a
DFS continuous waveform of any shape at any frequency, without clipping, at
a particular gain setting, (ie the 1/2 way specified) then it follows that
any lower level of signal input or volume control setting, will not cause
amplifier clipping.

TonyP.
Anonymous
May 12, 2004 3:48:48 AM

Archived from groups: rec.audio.tech (More info?)

"Fred Collins" <fredcollins7r@hotmail.com> wrote in message
news:55e592e9.0405102016.6ff9f100@posting.google.com...
> Mr. Krueger's statement that he does not abuse his amplifers in
> domestic listening may mean that he listens exclusively to
> limited-dynamic-range music or that he does in fact have 10 kW of
> amplifier power in his living room. As McIntosh literature trumpeted
> all through the eighties, given reasonable room sizes in more affluent
> American's homes, the inefficient speakers in popular use then (and
> now), and a desire to listen to orchestral music with the quietest
> portions clearly audible over an average residential noise floor-you
> need about 10 kW so as to never clip an amplifier. Alternatively, a
> pair of Teletronix limiters will keep things in order, anathema though
> this may be, most people didn't really want to hear those cannon shots
> all that loud anyway...

Since the music has already been through a compressor and limiter before it
got onto disk, neither a limiter or 10kW amplifier is necessary in the home.
Nor can you obtain 90+ dB dynamic range in any normal house, regardless of
amplifier size, without certain damage to your hearing.
Nor will many (any?) speakers handle 10kW, no matter how short the duration,
but most especially with those cannon shots!

TonyP.
Anonymous
May 12, 2004 8:59:02 AM

Archived from groups: rec.audio.tech (More info?)

"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:_bidnTTyE6GeOz3dRVn-tA@comcast.com...
> Karl Uppiano wrote:
> > "Fred Collins" <fredcollins7r@hotmail.com> wrote in message
> > news:55e592e9.0405102016.6ff9f100@posting.google.com...
> >
> > <snip>
> >
> >> Mr. Krueger's statement that he does not abuse his amplifers in
> >> domestic listening may mean that he listens exclusively to
> >> limited-dynamic-range music or that he does in fact have 10 kW of
> >> amplifier power in his living room. As McIntosh literature trumpeted
> >> all through the eighties, given reasonable room sizes in more
> >> affluent American's homes, the inefficient speakers in popular use
> >> then (and now), and a desire to listen to orchestral music with the
> >> quietest portions clearly audible over an average residential noise
> >> floor-you need about 10 kW so as to never clip an amplifier.
> >> Alternatively, a pair of Teletronix limiters will keep things in
> >> order, anathema though this may be, most people didn't really want
> >> to hear those cannon shots all that loud anyway...
> >
> > I'd have to disagree with you here. Playing a full-scale tone from a
> > test CD, my 100 watt/channel stereo amplifier clips when the volume
> > is set to the 12:00 position (1/2 way up). I *never* run my amplifier
> > anywhere near that high with any normal program material -- it would
> > be far too loud. With the volume set to less than 1/2, my amplifier
> > couldn't possibly be clipping with any kind of program material.
>
> Unfortunately this argument has problems of its own. There is very little
> that can be reliably determined from casual observation of volume control
> settings. The right thing to do is to measure the waveforms at the power
> amplifier output terminals.

That's exactly what I did. I have all of the usual test gear: Oscilloscope,
Noise/Distortion Analyzer, Low Distortion Sine Wave Generator, various test
CDs. I happen to know that a full scale 1000 Hz digital test signal from my
CD player clips at the output, under load, with the gain set precisely at
12:00. Digital full scale is the highest output ever attainable from the CD
player under any normal circumstances*, and 12:00 is a *much* higher gain
setting than I *ever* use, even for loud SPL. Those two taken together
guarantee the amplifier never clips. If A < B and B < C then A < C.

*A full scale square wave might have a little overshoot due to filtering,
but I'm not going to split hairs.
Anonymous
May 13, 2004 7:21:44 PM

Archived from groups: rec.audio.tech (More info?)

Tube amps are a lot easier to build and they usually are cheaper to
fix when they blow up. Solid state ones if designed correctly are more
reliable, but when they go they go catastrophically as do your
drivers. No SS speaker-protection technology is as reliable as a god
output transformer-why McIntosh still uses them.

If Mac coupled their autoformers and Power Guard to modern solid
state mechanical and device design and got rid of the meters-"Viagra
Goggles"-they'd have a pretty good amplifier.
Anonymous
May 14, 2004 8:13:16 PM

Archived from groups: rec.audio.tech (More info?)

"Sam Byrams" <samdotbyrams@hotmail.com> wrote in message
news:D 792394d.0405131421.23053114@posting.google.com...
> Tube amps are a lot easier to build and they usually are cheaper to
> fix when they blow up. Solid state ones if designed correctly are more
> reliable, but when they go they go catastrophically as do your
> drivers. No SS speaker-protection technology is as reliable as a god
> output transformer-why McIntosh still uses them.

Since the cost of a set of output transistors is usually less than one valve
these days, and don't slowly degrade over time, it's hardly something to
worry about.
Now lets consider the cost of that "god" output transformer!!!!!
That's why Mac valve amps are bloody expensive. :-)

TonyP.
Anonymous
May 14, 2004 8:13:17 PM

Archived from groups: rec.audio.tech (More info?)

"TonyP" <TonyP@optus.net.com.au> wrote in message news:<40a4638d$0$3034$afc38c87@news.optusnet.com.au>...
> "Sam Byrams" <samdotbyrams@hotmail.com> wrote in message
> news:D 792394d.0405131421.23053114@posting.google.com...
> > Tube amps are a lot easier to build and they usually are cheaper to
> > fix when they blow up. Solid state ones if designed correctly are more
> > reliable, but when they go they go catastrophically as do your
> > drivers. No SS speaker-protection technology is as reliable as a god
> > output transformer-why McIntosh still uses them.
>
> Since the cost of a set of output transistors is usually less than one valve
> these days, and don't slowly degrade over time, it's hardly something to
> worry about.
> Now lets consider the cost of that "god" output transformer!!!!!
> That's why Mac valve amps are bloody expensive. :-)

Matched N and P channel semi's aren't cheap, and Mac amps are high
dollar because of the perception of the buyer. The bifilar or trifilar
OPT, and later the autoformers, are substantially less expensive to
wind than the old UTC Linear Standards and Peerlesses-and the Sid
Smith reverse-engineered Fairchilds used in the Marantzes-that other
expensive tube amps used.
!