[Lance Hoffmeyer]

Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the amps side by side and
just switch the speaker wire from one amp to another) , will they both be equally loud if driven
at their 30 Watt peak?

Lance

[MC]

"Lance Hoffmeyer" wrote in message
...
Hey all,

Had a discussion with a friend the other day and he mentioned that a
30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt
of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more
efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything.
So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the
amps side by side and
just switch the speaker wire from one amp to another) , will they both be
equally loud if driven
at their 30 Watt peak?

Lance

If they are actually outputting the same amount of power, and neither one
has appreciable distortion, then they will be putting exactly the same
electrical signal into the speakers and there cannot be any difference in
loudness.

What your friend may have in mind is that valve amplifiers "clip" more
softly than solid-state amplifiers (in general), so you can drive the
amplifier above its rated power and get less distortion with valves than
with transistors.

[Chung]

A watt of power = a watt of power. This is a truism. That does not mean
that amplifers with a 1 W specification will sound the same driving the
same speaker, however.

A 30W amp may sound different from another 30 W amp because of any of
the following:

(1) The actual output powers being delivered to a given speaker load may
be different. Amp A may be able to deliver 60W into that load, and amp B
only 30W, for instance. Specified power may be quite different than
actual delivered power which is a function of loading.

(2) Related to the above, the output impedances of the amps can cause a
difference in available power and/or resulting frequency response into a
speaker load. This could be a large factor explaining why certain
low-power valve amps sound difference than solid-state amps.

(3) Some amps may clip more gradually than others. So one 30W amp may
actually deliver 60W at a distortion of 10%, whole another only 40W, for
example.

(4) Distorted waveforms can sound louder. So a 30W amp with 10%
distortion can sound louder than a 30W amp with 0.1% distortion when
both are delivering 30W into a given speaker load.

Lance Hoffmeyer wrote:
Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the amps side by side and
just switch the speaker wire from one amp to another) , will they both be equally loud if driven
at their 30 Watt peak?

Lance

[RalphH]

what about dynamic power?

--
Some of my angling snaps:

http://gallery.fishbc.com/gallery/vi...bumName=RalphH
"Chung" wrote in message
...
A watt of power = a watt of power. This is a truism. That does not mean
that amplifers with a 1 W specification will sound the same driving the
same speaker, however.

A 30W amp may sound different from another 30 W amp because of any of the
following:

(1) The actual output powers being delivered to a given speaker load may
be different. Amp A may be able to deliver 60W into that load, and amp B
only 30W, for instance. Specified power may be quite different than actual
delivered power which is a function of loading.

(2) Related to the above, the output impedances of the amps can cause a
difference in available power and/or resulting frequency response into a
speaker load. This could be a large factor explaining why certain
low-power valve amps sound difference than solid-state amps.

(3) Some amps may clip more gradually than others. So one 30W amp may
actually deliver 60W at a distortion of 10%, whole another only 40W, for
example.

(4) Distorted waveforms can sound louder. So a 30W amp with 10% distortion
can sound louder than a 30W amp with 0.1% distortion when both are
delivering 30W into a given speaker load.

Lance Hoffmeyer wrote:
Hey all,

Had a discussion with a friend the other day and he mentioned that a
30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt
of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more
efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say
anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the
amps side by side and
just switch the speaker wire from one amp to another) , will they both be
equally loud if driven
at their 30 Watt peak?

Lance

[isw]

In article ,
Lance Hoffmeyer wrote:

Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt
Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of
power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more
efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything.
So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the
amps side by side and
just switch the speaker wire from one amp to another) , will they both be
equally loud if driven
at their 30 Watt peak?

Without instrumentation, you cannot tell when you're running an
amplifier "at thirty watts" or at any other power level. Distortion can
cause a certain "wattage' of audio to sound much louder than if rhe
output is really clean. Heavily driven tube amplifiers distort in a
rather unnoticeable way -- some even like the sound.

Run the test with a 'scope hooked across the speaker to make sure
there's no clipping or other overload, and be sure to use the same
speaker for all tests. If the amps operate only in their linear region,
they'll likely sound the same *provided you do a really good job of
matching levels*; if you don't (and you can't without instrumentation)
the louder one will probably sound better.

Isaac

[Arny Krueger]

"Lance Hoffmeyer" wrote in message


Had a discussion with a friend the other day and he
mentioned that a 30Watt Valve amp is louder than a 30
Watt solid state amp.

A non-uncommon urban legend.

I thought to myself, not really, a watt of power is a watt of power.

Not necessarily. There are such things as clean watts and dirty watts.
Dirty watts often sound louder than clean watts.

What makes a 30 Watt
valve amp sound louder is probably more efficient
speakers.

Anybody who compares amps with different speakers would seem to be unclear
about how to set up a fair comparison.

Wanting to be polite and not entirely certain
I was correct I didn't say anything.

Good move.

So, given a 30 Watt SS amp and a 30 Watt tube/valve amp with the exact
same
speakers (put the amps side by side and just switch the
speaker wire from one amp to another) , will they both be
equally loud if driven at their 30 Watt peak?

If equally undistorted, yes.

Lance

[[email protected]]

On May 14, 5:59 pm, Lance Hoffmeyer wrote:
Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the amps side by side and
just switch the speaker wire from one amp to another) , will they both be equally loud if driven
at their 30 Watt peak?

Lance

This brings up one important aspect of sound systems. If two identical
sources each contribute the same 30 watts, it can effectively doubles
the sound intensity, or its like increasing power 4 times.

greg

[jwvm]

On May 15, 8:36 pm, " wrote:
On May 14, 5:59 pm, Lance Hoffmeyer wrote:

Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the amps side by side and
just switch the speaker wire from one amp to another) , will they both be equally loud if driven
at their 30 Watt peak?

Lance

This brings up one important aspect of sound systems. If two identical
sources each contribute the same 30 watts, it can effectively doubles
the sound intensity, or its like increasing power 4 times.

greg

You are confusing doubling the voltage with doubling the power.
Doubling the power is just doubling the power. If you double the
voltage to a resistive load, the power is 4X greater. This is the case
with bridge amplification.

[Chung]

RalphH wrote:
what about dynamic power?


If two amps behave differently when driven beyond the rated power, then
of course they may sound different at those high output levels.

[Eeyore]

" wrote:

This brings up one important aspect of sound systems. If two identical
sources each contribute the same 30 watts, it can effectively doubles
the sound intensity, or its like increasing power 4 times.

Not so.

There are some interesting coupling effects at low fequencies but if there were any truth in what you
say then everyone would be doing this and using say 10 x 10W amps in place of a single 100W one.

Graham

[Lance Hoffmeyer]

I am probably moving out of the realm of this NG but moving a step forward from
my previous question: What if we are referring to Guitar Amplifiers instead of
stereo amplifiers? Do the same rules apply? In other words,

Since there are clean watts and dirty watts and perhaps one goal to a guitar amp
is to be distorted and not clean (give me them dirty watts! LOL) , all other things
being equal (output wattage, ohm ...) are
SS dirty watts = tube dirty watts?

Lance

Lance Hoffmeyer wrote:
Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the amps side by side and
just switch the speaker wire from one amp to another) , will they both be equally loud if driven
at their 30 Watt peak?

Lance

[MC]

"Lance Hoffmeyer" wrote in message
...
I am probably moving out of the realm of this NG but moving a step forward
from
my previous question: What if we are referring to Guitar Amplifiers
instead of
stereo amplifiers? Do the same rules apply? In other words,

Since there are clean watts and dirty watts and perhaps one goal to a
guitar amp
is to be distorted and not clean (give me them dirty watts! LOL) , all
other things
being equal (output wattage, ohm ...) are
SS dirty watts = tube dirty watts?

Lance

Nobody knows because there is no standard way to measure "dirty watts,"
i.e., the performance of an amplifier when it is overdriven and
malfunctioning.

[[email protected]]

On May 16, 6:44 pm, jwvm wrote:
On May 15, 8:36 pm, " wrote:



On May 14, 5:59 pm, Lance Hoffmeyer wrote:

Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the amps side by side and
just switch the speaker wire from one amp to another) , will they both be equally loud if driven
at their 30 Watt peak?

Lance

This brings up one important aspect of sound systems. If two identical
sources each contribute the same 30 watts, it can effectively doubles
the sound intensity, or its like increasing power 4 times.

greg

You are confusing doubling the voltage with doubling the power.
Doubling the power is just doubling the power. If you double the
voltage to a resistive load, the power is 4X greater. This is the case
with bridge amplification.

You probably did not get my point, and it is exactly as I stated. You
gain effective power when you combine audio sources. With only a
doubling of system power using two sources, you effectively gain 3 dB
power.

greg

[[email protected]]

On May 16, 6:46 pm, Eeyore
wrote:
" wrote:
This brings up one important aspect of sound systems. If two identical
sources each contribute the same 30 watts, it can effectively doubles
the sound intensity, or its like increasing power 4 times.

Not so.

There are some interesting coupling effects at low fequencies but if there were any truth in what you
say then everyone would be doing this and using say 10 x 10W amps in place of a single 100W one.

Its true coupling is mostly done better at lower freqs., but to say
its not possible at 3 kHz is foolish. One of the things that make
large concerts possible is coupling. If the bass frequencies of all
those speaker boxes and all those individual amps had no combining,
the show would be rather weak. Many fail to comprehend the combing
effect, but its essential to be able to design speaker boxes with more
than one driver, else it will fail.

greg

[MC]

This brings up one important aspect of sound systems. If two identical
sources each contribute the same 30 watts, it can effectively doubles
the sound intensity, or its like increasing power 4 times.

It's like increasing the power 2 times or increasing the voltage 4 times.

30 watts + 30 watts = 60 watts, not 120 watts.

[jwvm]

On May 17, 7:07 pm, " wrote:
On May 16, 6:44 pm, jwvm wrote:




Snip

You probably did not get my point, and it is exactly as I stated. You
gain effective power when you combine audio sources. With only a
doubling of system power using two sources, you effectively gain 3 dB
power.

greg

You initially said that the power was 4X greater. A 4X increase is 6
dB not 3 dB.

[isw]

In article ,
" wrote:

On May 16, 6:44 pm, jwvm wrote:
On May 15, 8:36 pm, " wrote:



On May 14, 5:59 pm, Lance Hoffmeyer wrote:

Hey all,

Had a discussion with a friend the other day and he mentioned that a
30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a
watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more
efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say
anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put
the amps side by side and
just switch the speaker wire from one amp to another) , will they both
be equally loud if driven
at their 30 Watt peak?

Lance

This brings up one important aspect of sound systems. If two identical
sources each contribute the same 30 watts, it can effectively doubles
the sound intensity, or its like increasing power 4 times.

greg

You are confusing doubling the voltage with doubling the power.
Doubling the power is just doubling the power. If you double the
voltage to a resistive load, the power is 4X greater. This is the case
with bridge amplification.

You probably did not get my point, and it is exactly as I stated. You
gain effective power when you combine audio sources. With only a
doubling of system power using two sources, you effectively gain 3 dB
power.

At sufficiently low frequencies (where the waves from two sources can be
coherent at speaker-to-speaker distances; well under one wavelength)
each driver's pressure wave doubles the radiation resistance seen by the
other driver; that produces a corresponding increase in coupling
efficiency, and doubles the output power (i.e. to four times the output
of one of the drivers acting alone). It does not work at frequencies
where the drivers are separated by several wavelengths -- and remember,
the wavelength is down to about a foot at one kilohertz.

Isaac

[Norman M. Schwartz]

Hey all,

Had a discussion with a friend the other day and he mentioned that a
30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a
watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more
efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say
anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put
the amps side by side and
just switch the speaker wire from one amp to another) , will they both
be equally loud if driven
at their 30 Watt peak?

Effect of "damping factor, slew rate, recovery time and/or power reserve"
upon a watt = a watt?

[Eeyore]

" wrote:

One of the things that make large concerts possible is coupling. If the bass frequencies of all those
speaker boxes and all those individual amps had no combining, the show would be rather weak.

You'd be wrong about that. It's absolutely not necessary. The modern line array systems with large numbers
of drivers are used primarily for pattern control reasons.

The trend is also to very few very high power amplifiers too. 8kW in a single dual channel amp is quite
routine these days.

Graham

[MC]

"isw" wrote in message
...

At sufficiently low frequencies (where the waves from two sources can be
coherent at speaker-to-speaker distances; well under one wavelength)
each driver's pressure wave doubles the radiation resistance seen by the
other driver; that produces a corresponding increase in coupling
efficiency, and doubles the output power (i.e. to four times the output
of one of the drivers acting alone).

"Doubles to four times"? This is why people keep questioning the math here.

I think I understand the effect you're describing -- a sort of differential
drive effect, where 2 speakers move in unison to produce double the
amplitude (4 times the power) rather than double the power. Right?

But, as you note, that would work only at wavelengths low enough that the
waves really are still in unison throughout the space between the speakers.

[isw]

In article , "MC" wrote:

"isw" wrote in message
...

At sufficiently low frequencies (where the waves from two sources can be
coherent at speaker-to-speaker distances; well under one wavelength)
each driver's pressure wave doubles the radiation resistance seen by the
other driver; that produces a corresponding increase in coupling
efficiency, and doubles the output power (i.e. to four times the output
of one of the drivers acting alone).

"Doubles to four times"? This is why people keep questioning the math here.

Two speakers deliver four times the output power of one instead of the
expected two times; that's what I was saying.

I think I understand the effect you're describing -- a sort of differential
drive effect, where 2 speakers move in unison to produce double the
amplitude (4 times the power) rather than double the power. Right?

Nope. The effect I'm describing is what happens when the cone excursion
(think "current") does not change but the "load resistance" (of the air)
is doubled -- same current into twice the resistance produces twice the
power.

Without this effect, two speakers driven in phase will deliver twice the
output of one (and that's how it is at higher frequencies); with it, the
output of two speakers is four times that of one (at low frequencies).

But, as you note, that would work only at wavelengths low enough that the
waves really are still in unison throughout the space between the speakers.

Exactly.

Isaac

[Eeyore]

isw wrote:

Nope. The effect I'm describing is what happens when the cone excursion
(think "current") does not change but the "load resistance" (of the air)
is doubled -- same current into twice the resistance produces twice the
power.

The same thing happens when you increase the cone size. There's more to this than
you're apparently prepared to accept.

As I said before, if this method genuinely provided more SPL for fewer watts
everyone would be doing it.

Maybe the answer is there. It's SPL (the *pressure level*) we're interested in,
not the watts.

Graham

[Eeyore]

isw wrote:

Two speakers deliver four times the output power of one instead of the
expected two times; that's what I was saying.

Please explain precisely how. Since when did 2 sources of say one watt each add up
to 4 ?

Graham

[isw]

In article ,
Eeyore wrote:

isw wrote:

Two speakers deliver four times the output power of one instead of the
expected two times; that's what I was saying.

Please explain precisely how. Since when did 2 sources of say one watt each
add up to 4 ?

Stop thinking about electrical watts and start thinking about acoustic
watts.

At low frequencies, the pressure wave from each driver doubles the
radiation resistance seen by the other. The cone excursions (determined
by electrical power input) do not change.

It's the efficiency of coupling cone motion to that air that doubles. So
the same electrical input produces twice the output from two speakers in
each others' near fields as it would if they were far apart.

Isaac

[isw]

In article ,
Eeyore wrote:

isw wrote:

Nope. The effect I'm describing is what happens when the cone excursion
(think "current") does not change but the "load resistance" (of the air)
is doubled -- same current into twice the resistance produces twice the
power.

The same thing happens when you increase the cone size. There's more to this
than you're apparently prepared to accept.

Doubling the size of a single cone certainly increases output, but not
because of a n increase in radiation resistance. The two effects are
totally independent, and both can operate at the same time.

As I said before, if this method genuinely provided more SPL for fewer watts
everyone would be doing it.

Everyone *does* do it, even if they don't know it. For most stereo
speaker spacings, the two bass drivers are near enough together for the
radiation resistance to be raised. It's part of the reason that "stereo"
has better bass than when you sum left and right *and play it through
one speaker*.

Maybe the answer is there. It's SPL (the *pressure level*) we're interested
in, not the watts.

SPL is determined by *acoustical watts*; not electrical watts. It's the
acoustic output that increases because the radiation resistance is
doubled. The electrical input remains he same.

Isaac

[jeffc]

"Lance Hoffmeyer" wrote in message
...
Hey all,

Had a discussion with a friend the other day and he mentioned that a
30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt
of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more
efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything.
So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the
amps side by side and
just switch the speaker wire from one amp to another) , will they both be
equally loud if driven
at their 30 Watt peak?

Not necessariliy. It depends on how much current each can drive into
different loads, for example.

[Arny Krueger]

"jeffc" wrote in message

"Lance Hoffmeyer" wrote in message
...
Hey all,

Had a discussion with a friend the other day and he
mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself,
not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is
probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I
didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same
speakers (put the amps side by side and
just switch the speaker wire from one amp to another) ,
will they both be equally loud if driven
at their 30 Watt peak?

Not necessariliy. It depends on how much current each
can drive into different loads, for example.

Delivering a lot of current to a load is *not* one of those things that
tubed amps do well. All other things being equal, the best way to deal with
a tough load is to use a good amp that has a lot of reserve capacity, and
run it well below its maximum ratings.

[BEAR]

Lance Hoffmeyer wrote:
Hey all,

Had a discussion with a friend the other day and he mentioned that a 30Watt Valve amp is louder
than a 30 Watt solid state amp. I thought to myself, not really, a watt of power is a watt of
power. What makes a 30 Watt valve amp sound louder is probably more efficient speakers. Wanting
to be polite and not entirely certain I was correct I didn't say anything. So, given a 30 Watt
SS amp and a 30 Watt tube/valve amp with the exact same speakers (put the amps side by side and
just switch the speaker wire from one amp to another) , will they both be equally loud if driven
at their 30 Watt peak?

Lance

The reason that this claim is oft made is reasonably simple and straightforward.

(I did not read all the responses, but a random check of the threads did not
show the following response)

The key to your question is "at their 30 watt peak"!

IF neither amp is driven past their maximum, into any sort of clipping, AND both
amps have the same gain & sensitivity - meaning that they track output level
with input level exactly the same way for a given input voltage - then they will
not sound any different in loudness (in theory).

The variable on this is the spectra of distortion products, the absolute level
of said products AND the damping factor & bass response of the two amps - these
factors can make a difference in the way things sound and to some extent how
loud things are perceived. But in general the first conclusion stands.

Where the idea originates is in the zone *past* the 30 watt peak/maximum!

In the case of the typical solid state amp, hard clipping occurs (NAD has a
circuit to soft clip... some Mosfet amps tend to softer clip) in bipolar amps.
Hard clipping sounds, well, hard. Whereas the tube amp typically has very soft
clipping, and so can be driven on the input well past its nominal maximum. The
effect is a type of compression, which *does* make things sound louder and
usually will lack the audible artifacts of a hard clip. Of course at some point
just too much signal is being input and the amp really starts to sound ratty.

Why this works in practice can be seen by considering a typical amp playing at a
typical level, and then looking at the dB above average that the peaks are on a
given recording. It becomes clear quickly that if enough peaks cause an amp to
clip, the solid state amp being clipped may be quite audible while the tube amp
is being clipped without the same audible effect,which means simply that the
tube amp sounds like it can be played louder...

This is why it is oft said that tube amps "play louder" than a solid state amp
of the same power.

Fwiw, Zero FB triode A2 or AB2 amps do this trick in spades - the soft clip and
compression. :_)

_-_-bear