Amp for Apogee Stage's

Cjfrbw,

I think the "alliance" between Apogee and Krell goes back to
the days when Apogee was producing speakers like the Scintilla
and the "Full Range" which had very low impedances.

The Krells were practically the only amps around that could
drive these low impedances without going unstable. [ There's
a point a which an amp turns into an oscillator if the load
impedance is low enough. ]

That was Dan D'Agostino's and Krell's original claim to
fame - they were about the only thing around that could
drive Apogees without blowing up.

However, for many years Apogee recommended Classe' amps
instead of Krells. Although the Krells did an excellent
job of driving Apogees, and Apogee went to Krell for the
built-in amp of their "statement" product - the Grands;
they probably wanted to offer their clientele a more cost
effective solution. Classe' amps did a very good job for
less money than the Krells - although Classe' amps were
not cheap by any measure.

Measuring well is a necessary - but not sufficient
condition for accuracy. If something measures well, that
doesn't mean the system is accurate.

However, if the waveform presented at the speakers input
terminals doesn't measure well because the amp can't keep
up with the current demands of the speaker - then there's
no way that can be accurate - no matter how it sounds.

It may sound nice to some - the attacks and edges of the
music being rolled off, which some like the sound of; but
it can't be called accurate.

I'll look into the North Creek crossovers.

Dr. Gregory Greenman
Physicist

The H2O gives even the most demanding Apogee all the current it needs, plus, like I pointed out, set a new standard for leading edge, transparency, and decay.

I have heard Stages on a couple of occasions with Classe amps. While the sound was not bad, it did not really allow the potential of the Stages to present space and the Classes had greying, glaring, congestion and soundstage uncertainties that solid state seems to suffer from. I heard the Grands with Krells in a demo, and they sounded impressivey huge and dynamic, but also seemed to glare when I heard them. I used Melos Triode 200 high current hybrid tube amps on my Stages at the time, and I was impressed that they sounded better, but they did suffer from some softness by comparison. The Triode 200's, however, were superior in spatial presentation and timbre, and were easier to listen to.
When I use my Bel Canto Evo 200.2's full range through the passive crossover, they have the traditional virtues of solid state in lower midrange and bass control/damping. However, they are better than other sold state amps in attack, tone, and spatial addressing and separation, like tubes. The Bel Canto's seem to be somewhat musty as they go into the upper midrange, however. The H2O amps seem to have a better reputation in this regard.
The case for high current with the Apogees seems to be grossly overstated. I am currently using an active crossover with ASL 805 SET amps on the high ribbon. These are the most pathetic, current starved horrible measuring amps around and the sound is glorious and is vastly better than either the VTL 450 Sig monoblocks, Bel Canto Evo's, or the high current amps in my Yamaha RX Z9. No, I don't believe that I am in love with the distortion products, the amps are too simple in construction to pull any kind of elaborate tricks. A European audio critic that posts on the Apogee forum uses a 20 watt SET amp with the inefficient Calipers, and he says the sound is outstanding. At this point, I wouldn't trade the 805's for all of the Krells, Thresholds, Classes and Levinsons in the world. The 805's also drive the Stages full range through the passive crossover with aplomb and high volume levels, and the sound is not he least bit soft or impaired in the high frequencies. Rather, they tend to lack body in the lower midrange and bass, although the overall effect is charming.
Allen Wright is even working on a modest powered tube amp to use with the dreaded Scintillas, and if he manages it, I bet they will sound great.

Cjfrbw,

Unless you do the measurements, you can't know what's going
on.

I've put current limited tubes amps on the Stages - have seen
the tube amps strain, and fail to deliver the current needed
to compensate for the depressed impedance, and had audiophile
friends gush over how "liquid" and "lush" the sound was.

Then you put on the hefty high current amps - and they do put
out the current to keep the Stages accurate - and the
attending audiophiles complain about "glare" and being
"etched".

I think some audiophiles just plain LIKE some of the natural
rolloffs that tubes provide.

Even the simplest single-tube amp is not perfectly linear;
the output characteristics of a tube are not perfectly
linear - they do "roll-off" at higher signal levels.
[That's why you hear that tubes clip more "softly" than
solid state - they are NOT linear up to the clipping point.]

It doesn't take a complex amp to have these non-linear
characteristics - the basic characteristics of the tubes
have these non-linearities.

If you like that sound, fine - go with what you like.

Just don't fool yourself that your system is accurate.

Dr. Gregory Greenman
Physicist

Morbius, what are you using to drive your Minigrands?