Are There Any Inherent Advantages to Class A amps?

Mitch, if you want an amp / amps for just the bottom end and REALLY want them to thunder, save some money and buy some used Electron Kinetics Eagle 7A's, a Perreaux PMF-5150B, etc... It might take some looking and waiting, but you can typically find these for about $1000 - $1200 if your patient. If the demand goes up all of a sudden* or they are really clean units, figure $1200 - $1500. The big Aragon mono-blocks might also do the trick for you.

As far as your experience with the Sunfire Signature goes, i agree. These amps in stock form DO lack bottom end impact and authority. This was a real sore-spot for me with these amps. The newer models are better in this regard but they can still be improved upon. If you really just want it for bottom end, send it back to the factory and tell them to perform what Robert refers to as their "Apogee mod" to it. This changes the tonal balance quite drastically and will "thump" your woofers for all that they are worth.

If i personally was choosing between a Krell and a Pass JUST for use as a woofer amplifier, i would give the nod to the Krell in a heartbeat. If i was going to listen to the amp full-range, i would choose the Pass in a heartbeat. Obviously, these are my personal preferences, so take them with a grain of salt. Sean
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* Has anyone ever noticed that products that get repeated recommendations on the Agon forums tend to creep up in value? I've seen this with several different models, both here and on Ebay.

As others have stated - the Krell FPB "Class A" series are
Classe A up to their rated output.

A Class A amp can't switch to Class A/B - it doesn't have
the second "mirror-image" amplifier chain to handle the
opposite polarity. An amp that is Class A only has a single
chain - and it is biased so that it conducts during 100% of
the cycle - both positive and negative.

The Krell KAV series amps are Class A/B.

The advantage of a Class A amp is that there is no
"crossing distortion"; inherently. The amp does not
shuffle the load back and forth between an amp chain that
handles the positive half of the cycle and an amp chain
that handles the negative half.

In a Class A amp, a single amp chain handles 100% of the
cycle - so there's no distortion due to the "hand-off" to
the other chain - because there is no "hand-off".

Additionally, the latest offerings from Krell - the
"x-series" [ because the model number ends in "x" -
e.g. FPB-400cx] are somewhat of a departure from the
earlier Krell amps. They have gone away from the typical
"Krell sound" and lean toward a sweeter, more musical
presentation.

Dr. Gregory Greenman
Physicist

Dear Mitch: It can drive low impedances with out any problem and their bass reproduction is stuning.
Like I told you, you can get four of these exellent amplifiers for bi-amp. I agree with you that the best way to do the bi-amp is with the same model of amplifiers.
Regards and enjoy the music.
Raul.

bryston 6b and 7b appear to be decent values used for 500 watt monoblocks and most with years of warranty left....they can be wired up in parallel for different speaker types, too...2000 or a bit more for a pr

"A Class A amp can't switch to Class A/B--it doesn't have
the second "mirror-image" amplifier chain to handle the
opposite polarity. An amp that is Class A only has a single
chain--and it is biased so that it conducts during 100% of
the cycle--both positive and negative."

Morbius, that's not correct. You're confusing 'single-ended' with 'class a'. The first is a circuit-design principle wherein one output device does indeed handle both swings of the alternating-current signal. The 2nd deals with how much bias current is pushed continously thru the output device(s). Every solidstate class-A amp I know of (and that's not many) is push/pull and NOT single-ended.

These are 2 different design considerations.