"Arny Krueger" said:


It's pretty well known in the industry that the Krell
ratings sheet has been juggled by Krell. The 8 ohm power
rating was backed off, to create the impression that it is
an ideal amp and puts out twice the power into 4 ohms. If
the Krell amp were rated more conventionally based on those
tests that Sander's buddy Middius hates, there would be a
different story.


You're forgetting that the Krell also doubles current in 2 ohms.
The 8 ohms power ratings must be way, way underrated then.


The input impedance of the QSC amp is rather low,
something to keep in mind when driving it directly from
an opamp's output.

Most conventional audio-grade opamps have absolutely no
problem driving a 1K load to 5 volts rms, let alone just 2.
Ditto for modern preamps, whether vacuum tube or SS.


Then why does e.g. Sony advise to load their CD players with at least
50 kohms? Their output capacitors are at least 47 uF, so a low
frequency rollof wouldn't be a problem (for the math challenged, the
-3 dB frequency is then around 0.5 Hz).


The input sensitivity should have nothing to do with the
output load impedance, is this a typo, a mistake or does
the amp use such a high amount of global feedback that
the load has influence on the input? In the latter case,
problems might arise with strongly reactive loads, and
this may make for a different sounding amplifier.
I also noticed the DF isn't specified.


Shows that Sander can't see that the amps input sensitivity
is scaled to its output ratings into various load
impedances.


********.
A good amp is a constant voltage source, regardless the load.
That means the load should be of no consequence to the input level.
If there is influence, it's a bad design. Simple as that.


There are more issues to discuss, but that would require
more information about both amps, and, preferably, the
schematics.

Looks like having Sander comment on power amps is like
engaging the proverbial loose cannon.


You think the specs Mike gave are enough to determine whether these
amps will sound the same in a DBT, regardless the load?

Don't make me laugh.


Taking technical comments about SS amps at face value from a
tube advocate like Sander is very risky.


Taking technical comments about anything regarding audio on an Usenet
forum is very risky, no matter who the source is.

But given © that you seem to think of yourself as the "bearer of
Light" on audio newsgroups, I don't expect you to adhere to this view.


Party on, dude.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005