Question about Class A

If you get a chance to audition, the Luxman 509 and 590 are good.  They are much the same except for the A vs. A/B outputs.  It may help you figure out if Class A alone is worth pursuing for its own sake.

I have a Cary Super Anp with 2 monos on same body.

25 w a side an 200% constant for trannys 50 watts aside Class A.

k-88 .

Ran it 48 eight hours straight , just made my room hot ,

Makes a large jump in tone and depth in the classical and jazz I listen to ,on 2 main Quad and Totem that both take some power ! My 2K Omega’s are fantastic

on jazz with one driver , but 25 watt Cary is too much for them .

Point: Transformers are the heart of tube amps .

@jay73 ,

I think your speakers will be the determining factor regarding how tubes/class A will sound, and whether it will be 'better'.

Bob

Thanks for the recommendations.

Luxman will probably be out of my budget unfortunately, as beautiful as they are.

@gdnrbob , yes, you are right. I guess I won't know until I try it. Of course I hope it sounds good.

Cary Audio looks nice too but still above budget.

Unless I can find these units around $3K or under, probably won't work for me.

I think so far, the Sugden might be a good candidate.

As was already mentioned the efficiency of your speakers will greatly impact how well a low power Class A integrated will drive them. But having said that in or about your price range (Used) I would recommend a Cary CAD 300SEI or a Pass INT-30A. The Cary is Tube and the Pass is SS. 

Chuck  

Better to look for something used and go up the Sugden line a bit.

IME, in addition to higher heat and lower efficiency, there are also sonic trade-offs between Class A and Class AB amplification. After extended living with both, IMO it is not so much about one being better than another but more about selecting the type of amplification that sounds best with the types of music you listen to and with your specific speakers. Class A amplification can sound organic and natural (likely due to the absence of switching between A/B) but, at least in my experience, the trade-off can be a loss of dynamics or pure grunt compared to Class AB amplifiers of the same power rating. However, I wouldn’t get too hung up on the class of amplification since a good sounding amplifier is a good sounding amplifier regardless of class so it is more about what works best with your speakers and the music you listen to.

The Speakers that I have are Martin Logan Motion 40’s and they are rated at 92db sensitivity.

With the Vincent, I think they sound great.

From what I have read and watched, 92db should be sensitive enough for lower wattage amps but I am realistic, I know with some lower wattage amps and Class A, I may get beautiful mid-range but lack in the bass department a bit.

But I am not hung up on huge bass so maybe wouldn’t be a big deal.

I have three Class A amplifiers....A Yamaha M45 that is both Class A and Class A/B with the push of a switch, A Tubes4HiFi ST120 Dynaco clone Tube Amplifier and a Pass Labs First Watt F5v2.....Here is what I hear... The tube amplifier is magnificent. Easily the best sounding amp to my ears in my room with my speakers (KEF LS50 Metas or Magnapan MMG).....Try as I may, I can’t really hear any difference with the Yamaha M45 either in A or A/B.....The First Watt sounds like the tube amplifier. Fast tight bass, great midrange/vocals....Just one heck of a great sounding amplifier......BUT, Does it sound better than an ADCOM 555 or a Sound Artist SA200ia? ..... Not sure....There are so many great sounding amplifiers out there...Both past and present vintage.

I wouldn’t get too hung up on the class of amplification since a good sounding amplifier is a good sounding amplifer...

Good amps can be had in every class. Concentrate on good amps not design. 

Rogers High Fidelity EFH 200 Mark III !! Great tube integrated amp 100 watts / channel Class A. Hand made in MA w/ top quality parts & point to point wiring. Great sound, great build quality & lifetime warranty. Amongst the very best. 

Rogers High Fidelity EFH 200 Mark III...... And only 5X his budget!😂

Sugden invented it. Do it.

You might want to look at some of the newer GaN amps.  Those from LSA, AGD, and the upcoming amp from Atmasphere seem to embody a lot of the benefits of Class A amps without the absurd electricity penalty.  When Atmasphere is embracing and producing a GaN amp, you gotta believe the gap has been narrowed to near nil.  I’m a Class A amp fan too, but it seems to be a near dinosaur at this point. FWIW. 

I have 2 Class A amps. The KRELL K-300i integrated and KRELL Duo 175XD stereo amp.  The K-300i has the first 90 watts Class A. The 175XD has 175 watts Class A. They are not heavy, not hot, nor do they burn electricity at a high rate. Most importantly they sound amazing with very strong bass. 

I just hit an integrated Class A B Rotel A-14.

it’s all SS and sounds really good! Prior I had Peachtree Class D, PS Audio class D 

Arcam Class AB. 

the Rotel has better Bass than PS Audio or Arcam.

the Peachtree 150 was v good. But I like the Rotel

a lot- lots of Terrific features! I’m using it at softer vol

and thus it’s functioning in Class A most of the time!

it’s revealing as well/ 

I finally after Quad ESL, Quad amps, McIntosh,

and Boulder products decided to relax a bit !

My speakers are 4 and 6 ohm sets- no problems at all.

Rotel is a super bargain given the correct match between room and speakers.

Your weak link is the recording or file your playing!

If it’s recorded properly it will sound good. My gear sounds different if the file is at a low kbps etc.

Check out this CODA No. 11 power amp. About $2200usd. Pure class A, makes 100wpc into 4ohms.

Im extremely pleased with my CODA amp.

Since you can audition Sugden at the dealer in your area go take a listen and see what you think. Class A does make a difference if done right.

You may be surprised at how good Schiit Aegirs are at $799 each. Use 2 where each one is in mono mode giving you about 80 watts/channel into 8 ohms.

You will be very hard pushed to find something of better value.

Forget anything about marketing and of course Krell 175 doesn’t have 175 Watt Class A, even most of Pass Labs amps don’t. Normally you will have 20-30W Class A, producing a heat of more than 100-150W for that kind of power. I doubt there is a good cheap Pure Class A out there, because design, materials and heat dissipation will make it heavy and expensive.

There are some reasonably priced designs upto 10W but then you have to go with horns.

For speakers, if you choose SE (and for Class A IMHO only SE(T) has a meaning), not only they must be sensitive but also an "easy" load. Try to find a dealer that has such an amp and go and listen to it. You might not like it, or you may become enthusiastic about it (I am and cannot go back to anything else).

Regarding dynamics my Hydor 140W pure Class A rocks a house and its dynamics makes you jump from couch. But it is true, most of Pure Class A, due to low power and other compromises needed.

I happily am bound to efficient horns by my relatively inexpensive Dennis Had Firebottle SEP amp (12 to maybe 17 wpc)...bought it a few years ago when it was 3 or 4 months old for about 1200 bucks. Best hifi amp I've ever heard over many decades...Had is the Alexander Dumble of hifi.

The Sugden a21se is $3250, not certain where you are seeing an a21 for $2500. They do not go on sale. Any how, I love my A21se, best amp I ever owned. Yea, it gets hot, big deal. The trade off is holographic euphoric liquid sound. Nothing I’ve tried in past can touch it, it’s in a league of its own. Yea, there may be better and with more bells and whistles, but at what cost? I don’t need all that, I just want a pure class A single ended solid state amp, and I got the original, the sugden.

Did a little surfing. 
If it were me, and the power was sufficient, I'd try find a nice tube preamp, then try the Schiit first. Then, look at:
Sugden https://www.ebay.com/itm/255374915799?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338381866&toolid=10001&customid=8bd2bd48-88d9-11ec-bf81-623639343262
First Watt https://www.usaudiomart.com/details/649809695-first-watt-f7/
Krell, near St. Louis https://www.usaudiomart.com/details/649784277-krell-ksa-100-class-a-power-amplifier-w-original-box-packing-documentation/

I believe the krell amp has a fan and ibais which makes it run cool and it only uses a lot of electricity if it is being driven hard.

Class A power amp don't have an intrinsic sound.  The overall design of the amp is more important.  It's not like in tube amps where someone can hear the difference between EL84s and 300Bs.

@audioguy85  Ever get a chance to hear Sudgen's integrated one model up from the A-21se?

I think its called the i-4?

@audioguy85 A dealer in Irvine, CA is selling the A21 for $2400 actually (my mistake). That’s the one that I was referring to. The A21se, they sell for $3250 as you mentioned.

@cakyol The Schitt Aegir does look interesting. I looked into it a little bit. Seems like two use the Aegir as mono’s, you need to use the balanced input and my Vincent does not have Balanced outputs.

Also, according to reviews I read, when used as mono’s, you have to be connected to 8-ohm speakers although I saw a review by New Record Day on YT and he had them connected to 4-ohm speakers but I guess it’s not official by Schitt.

And Class A is for the first 10 watts and after that it goes into it’s "Continuity" Technology which is supposed to still sound close to Class A.

But as I said, it does look like an interesting option.

@jay73 You can find a used Parasound A21+ for around $2500. Which is what I paid for it. I traded it in for a KRELL 175XD but the A21+ was very good.

[edit] Oops. I did not realize you were referring to the Sudgen . However, have a listen to the Parasound. It is rather good and in the price range you seek. The first 6 watts are Class A.

Forget anything about marketing and of course Krell 175 doesn’t have 175 Watt Class A, even most of Pass Labs amps don’t. Normally you will have 20-30W Class A, producing a heat of more than 100-150W for that kind of power. I doubt there is a good cheap Pure Class A out there, because design, materials and heat dissipation will make it heavy and expensive.

Here is the marketing for the KRELL. iBias Technology – Krell (krellhifi.com)

Krell’s iBias Class A technology allows our latest amplifiers to run in full Class A mode to full power while minimizing heat generation. Previous efforts at using a “tracking” bias, while effective, only measured the incoming signal and set bias levels from this information. Our new patent pending iBias technology significantly elevates the effectiveness of previous designs by calculating bias from the output stage. This seemingly small change in topology results in a dramatic improvement in sound quality, especially midrange richness and purity.

Seems pretty clear to me.

I have to second the Krell K 300i with it’s Patent Pending I bias circuitry -  I have owned my Krell integrated for over two years and drive Maggie 1.7is. It fills the room with Class A sound and never runs hot. New it does cost $7,000 but if you find one used grab it - you will not be disappointed - build quality is amazing!

I’m using Pass Labs XA30.8 with Martin Logan Montis. Preamp is Pass XP-12. 
Incredible sound and never runs out of headroom no matter how hard I push it. 
Purity, dynamics and details in spades. 
I wouldn’t hesitate going with Pass Labs amplifiers. 

@yyzsantabarbara , you mentioned Parasound. I was actually thinking about Parasound also but maybe the A23+. If the A21+ puts out 6 watts in Class A then the A23+ might be half that or something, I am not sure.

But I suppose it could still sound good. Overall seems to get good reviews. 

The one thing I am confused about these types of amps is, at what point or volume, does it switch to AB from A.

With the Parasound, if I listen in low volumes, am I pretty much staying within Class A territory?

The Krell, as I said before, might be out of my budget but I will keep a eye out. But I have to say one thing (don't hate me for it, haha) but at least from the pics, the aesthetics do not look that attractive). I know, I shouldn't go on looks but performance.

The Nelson Pass First Watts might be an option to.

Damn, so many good choices. 

@rfnoise. +10

Great advise given thus far.  That Coda is a bargain.    Excellent amp, excellent service.   I have a Coda S-100 and won't part with it...  I also have Mephisto Solos,  Boulder 2050/2060 and Krell KAS amps.

Give the Coda a chance,  you won't regret it. 

Good luck in your search, 

Jose

Investigate GaN amps first. There are several threads on AG that should prove helpful (one is mine). As I recall, at least one person preferred the LSA Voyager GaN amp to Nelson Pass, PLUS, GaN runs cool (less electricity) and Underwood sells them for ~ $2500. I have owned one for over a year now, and every upgrade I make around it is immediately appreciated

I also had the LSA Voyager 350 GAN (modded by EVS). It is not a Class A sound. It sounds more like a Benchmark AHB2 with more low-end and can go down to 2 Ohms. I sold the LSA Voyager -> Parasound A21+ -> KRELL 175XD (happy with the KRELL). I kept the Benchmark AHB2.

The KRELL stereo amps are rather ugly and big. The K-300i is not too bad looking.

Here is a review of the Parasound A21+ that mentioned Class A and low volume listening.

Parasound Halo A 21+ Stereo Amplifier Reviewed - HomeTheaterReview

I owned the older Parasound A23 and I was happy to sell it. The A21+ was so much better than the A23. From what I have read the A21 is supposed to be a big step up from the A23. I would imagine the same for A23+ to A21+.

Just came across this Amp: Vision SET 400 Amplifier

Any opinions on it? So far the reviews I read seem positive.

AVA build quality value minded gear. Rave reviews all over the interweb.

The OP is looking for a Class A integrated amplifier.  Budget extends to 3K new/used.  The Sudgen A21SE used is the only one that comes to mind. Others?

BTW, I didn't suggest you buy a Luxman, but that the Luxman line has nearly identical integrateds except for the class A portion, so you could use them to compare and listen to the difference, to see if Class A was really a worthy goal all by itself.

Really appreciate all the feedback so far.

@erik_squires , Thanks for that clarification. That is a good point

@mesch, You are right, I was asking about an Integrated but with all the great feedback, now I am also considering adding an amp versus a whole new integrated.

I emailed AVA and Frank responded. I was inquiring about their SET 400 Amp and if he thinks it would be a good match for my speakers.

Frank actually recommended their SET 120 instead of the 400. So I am considering that also now and of course it is much less expensive so that is a plus.

The SET 400 is out of stock right now but Frank mentioned that they are working on a whole new chassis and that is going to take another month or so. Looking forward to see what they produce.

With all the feedback and now also seriously considering AVA Products with their great review and still being very curious about the Sugden, as suggested earlier in the thread, I am going to see if I can get a demo at the dealer that I mentioned and I need to inquire about their return policy.

What I may do, is purchase the A21 and the SET 120 and then compare in home to see what I like better. If the A21 comes out on top and I really like it, I would have to return the SET 120 within their 30 day trial period and I might just go back to the local dealer and exchange the A21 for the A21se.

Those are my thoughts right now.

At the end, I have to be happy with I buy and be content with it.

@jay73  I agree that the SET 120 would be the better purchase as you would not need the additional power. Are you talking about the integrated version or the amplifier? AVA makes both. 

What are your sources?  If digital you would have to replace the DAC in the SV-500. At your budget with purchase of the 120 integrated you could purchase a tube DAC if wanting some tube sound in your system.    

I must say that I once owned a Vincent hybrid amplifier, the SV-226. It was class AB. I sold it and consider that move one of my audio mistakes. It had more power than the SV-500 at 100wpc and was line level only. Fed it with an outboard DAC and phonostage for sources. I would encourage you not to be in a hurry in your decision making. Continue to explore.

I am still at a loss to recall a class A 20+wpc amplifier that retails for ~3K other than the Sudgen. Not to say they don"t exist.    

I personally am a huge fan of Class A.  In the Luxman 509x/590axII issue, one being A/B and the other, respectively, Class A, ask yourself why so many 509x units come up for sale, and not long after being bought, but the 590, a Class A unit, is only rarely for sale.  I think the fact one is Class A is the factor.  Once I experienced it there was no going back.  I am trying to get there myself......

Also to point out, there are MANY Luxman M 900u Class A/B units for sale......but the older M 800a Class A units are rarely for sale too and I wonder why.......

@mesch , as far as AVA HiFi is concerned, I would consider the AMP, not the Integrated or Control Amplifier as they call it.

Either the SET 400 or SET 120 Amps with the Vincent functioning as a Pre-Amp, I think it would make a good combo. As you stated about your previous SV-236, I really would hate to give up my Vincent. It certainly is a sweet sounding unit.

But if I decide on the Sugden, then no, choice, I would have to let it go.

For my sources, I have an external DAC (Queststyle CMA400i), MoFi Studio Deck TT with a Hana SL MC Cart and a Technics SL-G700 SACD Player. So I feel my sources are pretty decent.

Yea, I am not in a rush, need to make sure I get the right unit.

@blackfly , I've never heard the Luxman's but I can imagine they must be awesome, especially the 590 that you refer to. Just way out of budget though. But they are beautiful for sure.

But you stated, I really want to hear what Class A is all about, Hopefully Soon.

You’re going down the right road looking for class A, don’t listen to anyone who says that a properly made class D amp has the qualities you seem to seek. A, A/B, D etc. each have a flavor.  Although some A/B are biased for a handful of watts at the top. .

don’t listen to anyone who says that a properly made class D amp has the qualities you seem to seek. A, A/B, D etc. each have a flavor.  Although some A/B are biased for a handful of watts at the top.

IME You can't judge any amplifier by its class of operation. For example class D amps vary in sound just as much as tube amps do- some are quite nice, others make you wonder what the fuss is about. The 'flavor' of any amplifier is essentially its distortion characteristics.  Some designers know this and others don't.

@atmasphere

IME You can’t judge any amplifier by its class of operation.

wisdom from ralph yet again

people confuse technologies with results... those folks lack a fundamental understanding of engineering, which is to make specific technologies work to achieve targeted performance parameters

just like dacs when people say r2r sounds x, delta sigma sounds y... ugh...

This may not help, but it depends.  If you have efficient horn loaded speakers > 95 dB/watt-meter, you may hear a difference.  Most amps are Class A for the first five to 10 watts and switch to Class AB for higher power.  Class A is terribly inefficient, with a theoretical value of 50% conversion to power, the other 50% lost as heat.  In practice the value is 20-25%.  The amp is producing four watts of heat for every one watt of amplification power.

Here are two good technical descriptions about Class A without the audiophile voodoo

https://www.sound-au.com/class-a.htm

In short there is nothing wrong with Class AB.  Performance sound reinforcement, especially in arenas with rock concerts are running AB through PA speakers.  Try the Class A and see if you like it.  If you have the skills, they are very easy to build as there are thousands of designs in the literature.