[Audio Empire]

On Thu, 15 Mar 2012 10:07:40 -0700, ScottW wrote
(in article ):

On Mar 14, 7:58=A0pm, Audio Empire wrote:

[quoted text deleted -- deb]

Actually, within certain parameters, modern solid-state hi-fi
amplifiers do sound the same. Ideally, an amplifier is defined as "a
straight wire with gain". With modern solid state design, this is not
too difficult a goal to achieve. The differences, when they occur, are
usually down to design decisions made with regard to final selling
price. The circuit topologies that yield theoretically "transparent"
amplifiers are well known by all designers and are neither expensive
nor exotic to execute.

Take two 150 Watt/Channel designs. One sells for $600 and the one
sells for $2400. What is likely to be the difference? Well, cosmetics
aside*, the difference is likely to be the power supplies. Pry open
the $600 example and you are likely to find a single torroidial power
transformer feeding both channels with single bridge rectifier and a
couple of inexpensive electrolytic capacitors in an RC Pi network
feeding the circuit boards for both channels. Pry open the $2400 amp,
and you'll likely find either TWO torroidial transformers or one much
larger transformer. If two, then they are likely to be larger than the
single torroid in the $600 unit. The single transformer likely will
have separate windings for each channel, each feeding a separate
bridge rectifier, and separate filtering networks that are =A0usually
much larger than the network in the cheaper amp, and perhaps the $2400
amp will have both channel's power supplies bypassed with audio grade
caps and perhaps even have regulator circuits applied to the voltage
rails.

Will they sound different? Under normal loads and at average listening
levels, it would likely be difficult to tell the two apart in a DBT.
However, if pushed to high volume with very wide dynamic range
material into relatively low efficiency speakers, the the amp with the
bigger, stiffer =A0power supply will likely sound better.

All this exercise demonstrates is that rated power output into a
single
load spec is insufficient to define an amplifiers performance
capability.

For example, digging further into these amps performance
characteristics
one would likely find the well designed amp can deliver 300 watts into
a 4 ohm load
while the lesser amp will probably not.
Anyone who looks no further than a single power rating spec into an
undefined load
for amplifier performance and is surprised by differences is simply
not doing their homework.

Congratulations! You have managed to miss the point entirely - which
was that modern solid-state amps differ only in things like power
supply design and superficial circuit topology and the degree of fancy
case-work. otherwise, class AB amps are all pretty similar and under
normal listening conditions are all pretty much transparent -
regardless of cost. You have to stress most amps in some way before
any real differences make themselves known.