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wrote:
"Sander deWaal" wrote in message
...
" said:

Krell 350 Watt monoblocks @ $17,500.00 per pair
350 watts wpc @ 8 Ohms
700 wpc @4 Ohms
1400 wpc @ 2 Ohms
Signal to noise = 118db 95 db @ 2.83 V
THD = .05% 20 Hz - 20 kHz
Input Impedance = 100 K Ohms
Input Sensitivity = 2.6v RMS for max power
Voltage gain = 26.4 db

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QSC PLX 3402 Stereo amp $1200.00
700 wpc @ 8 Ohms
1100 wpc @ 4 ohms
1700 wpc @ 2 ohms
Signal to noise 107 db
THD = .03% 20 Hz - 20 kHz
Input Impedance = 6 K ohms
Input sensitivity = 1.9 Volts @ 8 ohms
Voltage gain = 32 db

One of the things that I noticed immediately is the ability of the
Krell to deliver twice the power (meaning current) in half the load,
up to 2 ohms.
I suspect that even in 1 ohm the figure would be close to the required
2800W, be it for a brief period of time.
The QSC has only marginally more power into 2 ohms (not that those
insanely high wattages have any meaningful use, you will note).
Also, the current doesn't double with half the load.
This means the Krell has a stiffer power supply, despite the lower
average wattage. It is a true constant voltage source.

You've jumped to a conclusion that's not borne out by the figures. The
power output into a variety of load impedances is simply part of the spec.
It does not mean that the power output of the Krell will double just by
changing the load from 8 to 4 ohms.

BS. Power output is either current limited or voltage limited.
Obviously into an 8 ohm load the amp is voltage limited. The QSC is
also voltage limited into 8 ohms but becomes current limited into 4
ohms.
IF the QSC is driven to max output into 8 ohms with 1.9 V rms input it
will suddenly find itself current clipping if that load is increased to
4 ohms. The max input is now only 1.7 V rms. Since the gain is the
same the useful dynamic range of the amp is reduced.

In other words, it has nothing to do
with the "stiffness" of the power supply.

I guess we differ on the meaning of "stiffness". In my opinion...
the power (current and voltage) capability of an amp is very dependent
on its power supply.

What it DOES mean, on the other hand, is that the Krell is a 1400W amplifier
designed for optimum performance into a load of 2 ohms or less. Since the
output is voltage limited, it's an inefficient amplifier choice for an 8 ohm
speaker.

Excess current capacity may bother you, I like it. It makes the amp
more versatile and acceptable for use with virtually any speaker. The
QSC suffers degraded dynamic range with load and the specs also show it
suffer increased THD into 4 ohm loads as well.

ScottW