Class A amplifier choice, need suggestions

What is your favorite class A amp and why? There are many here on Audiogon... Levinson, Krell, Pass Labs, Plinius and an occaisional Accuphase A50V. I am driving Proac Response 3.8s (88dB efficiency). I recently auditioned a Pass Aleph 5 and was stunned by the presentation at only 60wpc.

Your input is much appreciated!
I also was stunned with the Aleph 5. I initially heard it on a pair of Wilson Watt/Puppy 6's and was amazed. It's the only class A amp I've owned so I can't compare it to others, but I've had Krell KAV250a before and it blows it away.

I've heard Levinsons at my dealers before and at the price of a used Pass Aleph, I'll take the Pass.
My favorite is the Pass X600 monoblock. It operates in class A up to 100 watts continuous (200 watts peak), then shifts into class AB mode. While it doesn't go up to the X1000's 1000 watt max, its 600 watts of rated continuous power is more than enough for most applications, and it doesn't have the X1000's power connection idiosyncracies. It sounds terrific in the midrange, pretty good in the high end, and OK if not super in the bass.

I currently own an PS Audio HCA-2, which is one of the cheapest class A rated amps (by Stereophile) in the world. The sound is awesome... very fast and tight bass, transparent and grainless trebles, female voice sounds exceptionally good. I had it run for 5 straight days and the amp wasn't even warm when touched. Since I don't have a dedicated circuit, the amp's 95% power efficiency really help. When I first had the amp, I did experience ground loop hum. After I lifted the ground (by removing the ground wire from my PC), everything went silent. This amp is driving the Tyler Acoustics Linbrooks with outboard crossovers by the way.
Disclaimer: I am in no way associated with PS Audio or a dealer. I am just a very happy audiophile who bought an outstanding product at an affordable price.

Good luck with your search for the perfect amp!

I am using Jadis JA-80 with Proac 2.5 , it is very warm, musical and delicate sound. I am only listen to classical music, I think Proac has perfect match with class A tube amp. It is smooth sound in high and very warm in Midrange.
U can try Aleph 0 monoblock, it should be good choice.

Good luck
I run 87db speakers @ 8ohms in a room 16x26x8 and rarely measure 90db @ 1m. The amp sounds exceptionally well in my system and will fill the room with enough volume to hear it outside (4 sound room walls are insulated with r12 with r20 behind that on three walls and cement foundation walls on three walls and the ceiling is r12 with a sound barrier utilized between it and the subfloor above.

I couldn't justify the ML 33H price and am satisfied that the 5 is a greater value and a near equal performer!
I agree with JamesWei. The Pass X600 is one awesome amp. Unbelieveable with Revel Salons.
Need solid Class A advice contact Jon Soderberg at Jon worked with Nelson Pass at Threshold for many years. Bought a Forte Model 4a Class A amp from him and could not be happier. He may have something you can use,or get some really first hand advice from him. He did have a killer Threshold SA 3 Class A amp for sale a few weeks ago.
For solid state amps you really can't go wrong with the Pass Aleph series. I have Aleph 1.2 monoblocks and think they are fantastic. I have a friend with Pro-Ac speakers and he drives them with tubes and they sound great even though the amp is class A/B push-pull. You may not want to limit yourself to pure class A amplification.
Once again, I think we may have some semantic confusion going on here between class "A" amplifier bias operation, and Stereophile's 'Class A' of their Recommended Components listing.
Zaik correct: the PS Audio is not biased class A at all; its digital PWM output is, if anything, biased toward class C (which is actually not biased at all, but at cutoff).
In the class A catagory - I love my Accuphase; my Ayre amp isn't half bad either.
I love Levinson stuff, but recently demoed and bought harmonic precision amps from star sound tech. These are 110 wpc into 8 ohms and over 97% efficient. Almost no heat. Unbelievable sound and incredibly dynamic. I am driving revel studios with these which I previously drove with 250 wpc levinson amps. I thought they couldn't be as robust as the MLs and when I first got got them thought they were muddy slugs. However after about 300 hour burn in it was a revelation. These things have opened up so much it is hard to describe. They get better on each listen,truly warm and dynamic. I really thought I was listening to tube amps. Someone who is respected in the business ought to evaluate these amps. I have heard and used a lot but these are remarkable.
Love my Plinius SA100 MKIII
magic midrange, smooth highs, articulate bass
The Plinius SA-102, 125 watts pure class A. Read my review and you will look no further.
Thanks to all of you for your help! It is with your help that I found and purchased a Pass Labs Aleph P Class A preamp with adjustable gain right here on Audiogon, and I am sure I can do the same in my search for a class A amplifier. I will make it a point to check out all thses suggestions.
The McCormack DNA-2 Revision A may still be a class A/B after the upgrade, but it's very powerful and musical. Mine does run a bit hotter since the Revision and the bias may have been tweaked. My speakers are 88db efficient also and you'd be impressed by the effortless control provided by this amp.
It's 300w/600w/1200w from 8 to 2 ohms. Check the classifieds.
I haave not heard anything better in solid state class A then Symphonic Line Kraft Reference 400 and 250, either stereo or mono.
Gvatchna, you beat me to it. IMO, the Kraft ref 250 class A stereo should be sufficient for the 3.8's. I heard mine driving a slightly bigger Proac and was very impressed by those speakers.

But, Detlof's Jadis -- ahhhh.
class A in terms of rating or class of operation?
basing on the above answers I believe that class A in terms of rating is being searched.
plinius(basically any model) is a great choice when driving low-impedance speakers. SA250 has a long margin of class a(upto 35W?) and than switches to B for more current. McCormacks are all bright and extra-coloured. Pass Aleph 5 is great but has a bunch of limits of performance if played something more than chamber or small-band music.
another great choice is GamuT D200.
Solid State Amplifier: Pass Labs X350 or higher
Vaccum Tube Amplifier: Audio Research VT200 or higher
My bad...
I am courting suggestions on the purchase of a class A biased amp. Evidently, many of them are also Class A in quality.

My apologies and many thanks!
Sleeper of Class A amps: Yamaha M80 The whole M series is awesome. It was just as clean as my Threshold, just not as warm. Handles 3 sets of speakers and has built in gain control. Awesome bargain.
Plinius SA-100 MkIII makes me happy. Very warm detailed sound, great bass. SOUNDS BETTER IN CLASS A MODE, but I also believe you shouldn't limit yourself to class A. I'm looking to experiment with a good tube amp when life settles down a bit. The Cary 805c is supposed to sound good w/ my speakers as well(Silverline SonataII-which I adore).
I know they're a bit rare, but let's not forget the BEL 1001. Exceptional performance and often overlooked because you don't see them for sale much.
The Kinergetics KBA-75 may be the best value in this area, they can be had for $500-$650 and while not the best of the bunch here, are cheap for a starting point.

Don't forget about the rarest (and ultra high quality) Class A amps (at least in the US), Gryphon has been making strictly class A for a lot of years and now they have a massive class A model as well as a more massive class AB. If you want a room heater, this is what you need.
I just found out that Plinius amps work in class A to the whole rated power into 8 Ohms. Into 4 ohms they switch to class B depending on the power needs.

Where did you learn this about the Plinius?


to be more precise SA series work in class A at whole rated power in to 8 ohms. that i learned from the manufacturer. i 90% tend to believe due to their huge massiveness of the chasis and real worm sound.
Correction: The Pass 600 idles at 600 watts giving it 150 watts of Class A. I used them on 4 ohm Apogee speakers without budging past the idle current flow even at high decibles. I'm using it on the 1 ohm Apogee Scintilla now, and at moderately loud volume, it still doesn't move beyond class A. When I crank it way up, yes it does move to B on heavy transients, and I don't detect a difference, the amp runs so clean.
Pass' Peter Perkins informed me last spring that he underwstands that the X600 operates in class A up to 100 watts continuous and 200 watts peak. This seems to corroborate the 150 watt (effective average?) Muralman1 cites. An interesting side note was that he described the X1000 as generating 90 watts continuous and 180 watts peak in class A. Obviously, the X1000 goes higher than the X600 in class AB. I conjecture that the X1000 may generate more heat per class A watt and that the heat dissipation capabilities of the chassis and heat sinks (same for both amps) are a limiting factor in setting the class A bias.
For value...Musical FIdelity or creek...
AtmaSphere tube amps, without a doubt work well with my 3.5,s though I'd love to hear from anyone that has compared the proac 3.5,s with the newer 3.8,s
anyone have any idea what a pair of threshold sa/1
mono blocks are worth??

I have a pair, they sound awsome but I have no room for them..

Jademo is right,Just read his review on 102,For me its
one of the best sounding amp I have heard. pass aleph
are also goods amps, But side by side comparison, My
friend and I we both decided Plinius sa 100, is more
musical,with the 102 IMO very few amp can touch it,
for the price and overall performance.Its that good.
my 2 cents.
I am very enjoying my Pass Labs Aleph 2 (pure class A 100Wx2) + ARC Reference II MKI + Genesis G-V (active woofer). In my opinion, Aleph + active speakers is a perfect combo. Aleph is very sweet, warm and smooth for the top end and midrange. However, the weakness is the bass control due to its design. An active woofer speakers can make up Aleph's weakness.

To drive a passive speaker, you might try stepping up to the higher Aleph 1.2 (200Wx2). However, if you'd like to have more bass control, Pass Labs X-350 or above are also good choices. With X's, you sacrifice a bit sweetness and warmness, but you earn more bass control. It is depending on your taste.
Blueswan ,

I think you asked about power amps operating in class-A mode & *NOT* power amps listed in the class-A section of Stereophile!!! Zaikesman pointed this out correctly. I feel that should have been clarified. S'phile should never have labeled their classification "class-A, class-B", etc 'cuz these are bonafide operating modes of power amps & electrical engineering terminology. What can I say.....

Anyway, my recommendation (other than 2nding Gregm & Gvatchna re. the Kraft 250) is the Clayton Audio S40 stereo amp or the M100 mono block. I have not personally heard it but read reports from both professionals & private citizens who have used it in their systems for ~2 yrs.

The Claytons are not a flashy amp but they seem to do everything correctly. Each of the users were very happy w/ their purchase. Several reviews available on Soundstage! in their archives & *maybe* even S'phile.