Demo'ing Class A amps, Appreciation Suggestions from those who recently been there

If you can find a great price on a used Krell Duo 300 XD I’d grab it in a heartbeat. You cannot do any better in Class A than the latest generation of these Krell amps. Luscious, syrupy sound, Beautiful sound staging and the famous dynamic punch at the low end  Krell is so famous for.   

Wilson Shen, claytonamp@aol.com I have dealt with him several times. 
l find it hard to believe he is no longer in business. I am using a Clayton  S-40, 2 pairs of M-100 monos, and 1 pair of M-300’s.
Super Performers. My favorite system features Avantgarde Trios with Class A mono blocks custom built by David Berning. These are OTL tube beauties which put out something like 10 or 15 watts each. I have 2 pairs of Omtec CA-25 mono blocks, built in Germany by Manfred Baier.  About 30 watts per block, class A solid state. They are available for a song if you are interested, as I am near the end of my life. Some advice, seek out the individual designers with small dealer networks, and work one on one with them. This is the heart of our hobby, individuals.  It is where the fun is. We all go defunct at times, and usually we rise from the ashes.  Good luck.   Joel 

Lowtubes,

I must admit this thread has done more to my considerations than
I had expected. Particularly as to whether I will find the SS route a 
mistake.  Threshold is Pass's first company's Class A Amp. Is this not
"edgy" as the XA25? 
I like the extra dynamics and bass of the SS Pass but it does burn
a little bit on the top end over time. I adjusted my Tannoy treble settings
downward to help this. 

Audioguy,
I did try the Masterclass IA4 by Sugden last week.
It was fine but not anything exciting to listen to.
Odd as I had higher expectations for it.

Joel,
Thanks for the contact info.
I could not find a website for Clayton when I checked.
I had hoped to hear about some good options and certainly
have. Thank you to all for contributing to this thread.
I know nothing of the Omtec brand but it sounds interesting.
Can you pm me some info?

Well as long as you have opened the door to a tube integrated, you might want to check out the Raven Audio Nighthawk MK3 if you can live with 20 tube watts per channel 
https://www.ravenaudio.com/product/nighthawk-mk3-tube-amplifier/
People seem to think they are very good in the $3k range.  Made in the  USA if that matters and from what I have read a great company to deal with.

I have not heard this integrated, just watched the show footages.

Chorus, I used to like my SS amps a lot but when I moved up to very revealing cables, my SS amps do not sound like music as much as my tube amps which are 300b, EL34 and KT66 based.  The Threshold SA line and “T” series are truly wonderful sounding SS amplifiers and awesome in every way. The long history of online comments on these amps speak for themselves. But ultimately, it’s which amp sounds best in your system. BTW, I’m sorta bias in that I’ve experience quite a bit of components that were very expensive and did not live up to a high standard. I like to stick with what has been proven and tested by many many to be top performers. 

Lowt,

So if I keep my mid-line interconnects, cables and power lines
I will likely be okay with SS then.

Who do you consider to have an opinion of real value?

I want gear that is:
1. Under 5 years of age. Preferably 0-2 years.
2. No defunct companies. No time to chase parts. 
3. Products that have had universally good reviews
4. Products I can try out in my home before owning.
5. Most importantly-that they have a highly involving sound.
6. Then there is that darn budget thing-$5k max.

Thanks

Blow your mind! https://www.audiogon.com/listings/lisa10i0-krell-duo-125-xd-solid-state

I have been counselled to avoid the Krell brand due to breakdown
issues. I am intolerant of anything needing regular repairs.
Life's is too short.  
That said several people have suggested Krell in this thread.
So it must have good SQ. But the repair question is offputting.

Smooth Class A, try the Belles SA-30, I just got one and it is sounding wonderful 

@gryphongryph 
Smooth Class A, try the Belles SA-30, I just got one and it is sounding wonderful

A photo of the inside, 2 large torrids, clean layout, 4 OPTs per side. Never got a chance to hear one to compare. Nice.  Does it sound fairly neutral to your ears, or extended in any way?  


https://www.hifisentralen.no/forumet/attachments/hi-fi-generelt/393431d1470850201-klasse-klubben-sol...

That is a sweet look!
When was the last one manufactured?

I was in your boat last week... Went from separate pre and class a mono into tannoy arden (new legacy) and wanted to simplify. Got an ex demo luxman 550ax2 for £3k about $3700 looked as new and it beats my more expensive setup in every regard. Effortless layered and a wicked MM MC stage built in to boot.

I've had linn magik dsm in the past... I'm not a fan of their amplification... Detailed but. Leaves me cold. 

If the 550 this good makes me wonder what the 590 does. I always sniffed at intergrated but there is a Synergy there difficult to beat.

Only problem going to one box is being left with phono stage, interconnects and an excess of kimber power leads.... 

Luxman 550 states. Only 20w but tannoys 94db and I barely get to 10 o clock on volume dial before it becomes too loud. They say it goes to AB under demand but not seen anything in writing. Beautifully built and I see know why you see 30year old luxman up for sale still at good prices. 

Sugden also very good but more $ in the US compared to UK so value for money might become relative issue. 

If u decide to stay tube, give a Line Magnetic 518ia consideration. SET, 22wpc, but very capable watts.  4/8/16 ohms taps available.  A little hum, yes.....but gloriously musical. Best of luck in ur search.   

@decooney - I am very impressed by the sound, very good soundstage with beautiful decaying of instruments, I did not expect so much right away as I am using the pre out of my old intergraded amp, but I can live with this sound happily until I get a tube pre.

I think it sounds neutral, the bass is very good, very live, the treble sounds extended too me, but the midrange is just wow, very good tonally and at the same time very clear.

My hybrid amp gave some more atmosphere, like being in a small nightclub listening to Grant Green, but when I get my tube pre I expect that to come back, the SA-30 has much better resolution than my hybrid, that’s for sure.
    
The amp design looks real quality, very thick front, back and top plate, nothing ringing when you knock them, only tender knuckles ;-)

A very faint hum can be heard if one puts the ear close to the amp, but the speakers are dead quiet with full output on the pre.

It does get very warm though, so good ventilation is important. 

If tube amplification is an option, my suggestion would be Linear Tube Audio. I am using a ZOTL 10 amp with the MZ3 preamp on Spatial Audio M4 Triode Master speakers. The speakers are rated at 93db and average 12 ohms. These are open baffle speakers and are probably getting around 8 watts from the ZOTL 10 amp. This amp can drive me out of the room if I cranked it up, so it has plenty of power for normal listening levels. I believe the amp puts out 12 watts at 4 ohms.

These amps are very different from a normal tube amp with normal transformers. They have a frequency response that goes down to 6 hz at -0.5 db which gives you the bass response of a ss amp. They have no massive transformers and the tubes run at much lower amperage than a normal tube amp. The tubes are supposed to last between 10-20 years and the heat generated is less than a normal tube amp or a Class A ss amp in my experience. LTA amps and preamps are dead quiet with no hiss at all. I went from using a Cary Rocket 88 tube amp to a CODA 10.5R ss amp (100 watt, 25 watt Class A) to my current LTA system. LTA describes their sound as tube tone with solid state detail which I think is very accurate.

They have a two week trial period and will take back the amp for any reason and will cover the return shipping. The ZOTL 10 power amp is $3,200 and they have a Z 10 Integrated amp for $4,900.  

@aldoallen
..LTA describes their sound as tube tone with solid state detail which I think is very accurate...
--------

aldoallen,
A friend who’s owned the same tube and SS amps I’ve run described his ZOTL amp the same way as you have, and LTA does on their site. And, we’ve both owned solid state amps which have "tube tone. Friend indicated his ZOTL can be "less tubey" sounding, and therefore kept a few of his tube amps to rotate in/out periodically. Been asking him to roll some different tubes in it to compare again.

The other comment on the LTA site about tube amps is... "but their “warmth masks details and can sound thick.". Yes, true for some tube amps, not all. Particularly not with more modern amps with modern power tubes like KT150s. Seems LTA/ZOTL was looking for a hybrid sound and approach. It’s great to see different approaches.

I would’n’t mind demo-testing the ZOTL40 Reference amp with my custom speakers, to see what it can do, and how different it is versus some of the more capable Class A>A/B solid state amplifiers we all know. Grew up past 40 years transitioning through very "tubey" sounding solid state Mosfet designs with dual mono torroids and really enjoyed those too. Then, on to tubes. Have great appreciation for those blending both together.

Noting you’ve owned CODA and the Rocket88, both with their own signature sounds, do you feel your ZOTL leans more to SS than tube amp sound then? If you could change the sound a bit more with your ZOTL, what would it be - if anything?

Dennis Had 'Inspire Fire Bottle' SET tube amp is an option.

Based on online measurements, the Luxman 550 seems misleadingly underrated when it comes to wattage. I suspect this has to do with meeting test standards requiring pre-conditioning.

I'd treat it as a much larger amp when considering it's application.

Decooney:

I would say the LTA amp leans more toward very good solid state and less towards lush tube sound. Compared to my CODA amp it has a little more detail and adds some air around the individual instruments and voices if that makes any sense. It is hard to describe and I think the best description is tube tone and solid state detail.as LTA describes it. I was not satisfied at all with the Rocket 88. Even though it could put out 60 watts, the bass disappeared on my open baffle speakers and I don't listen much to bass heavy music. The CODA corrected the bass problem but it was barely idling running my speakers and most of the 25 watt Class A was going to heat the room. I took a chance on the LTA amp based on what I was hearing from the MZ3 preamp and I am very pleased with it. It still amazes me that this little 10 watt tube amp can drive my speakers as well as the CODA amp and the CODA is is a very fine amplifier also.
The LTA amp came with four Russian 6P14P-EB tubes and four 7062 tube that are unmarked but I think may be RCA? I suppose the tube sound could be adjusted by using different tubes but I like it the way it is.

 I can't think of anything sound wise I would change but it is definitely not audio jewelry. Just a plain black box.  

Audioman58 - here is a big Hell Yes concerning the new Krell K300i!! I have been running mine for 6 months now into my Maggie 1.7is. This integrated has no issues pushing my Maggie ‘heat sinks’ to new levels of performance. The new circuit design keeps the amp portion in Class A for quite some time - I should know - I push the most inefficient speakers and I can run you out of the room.  I wanted more bass - so I bi amped into the Maggie bass panel by adding a Son of Ampzilla II just for the bass panel . The Krell has a preamp out (that is adjustable) to match volumes. 

Just my 2 cents

Happy Listening and stay healthy!

In reference to your fear that Krell needs a lot of service - I am a Krell owner for 15 years - using three different integrated amps over 15 years - I run two stereo systems in my home. Over that 15 years my Krell’s needed service twice.

As far as I am concerned - that shows a very high quality standard.

just my personal experience !

Happy Listening and Stay Healthy!

@aldoallen
.. I can’t think of anything sound wise I would change but it is definitely not audio jewelry. Just a plain black box...

aldoallen,
Congrats. It is unique black box. Not like most other 10w amps. My colleagues ZOTL displaced a former Cary -and- Dennis Had Inspire amp (all stock, unmodified) yet he does like detail and fast punch over lush-plush-bloom triode tube sound. And, to read yours displaced a Coda 10.R SS with the first 25w in Class A - is notable. Synergy with speakers is everything. Glad u found it for your ears and prefernce. :)

Keep your eyes peeled for a used Luxman L-590 AX II. Probably the best value on the planet. As for Accuphase have owned three of them, an E-470,  E-600 and now own the E-800 (the last two are Class A.

If if I had to select one integrated for dollar for dollar value, it would be the Luxman. It does everything so well and the specs are way understated.

Chorus, 
       I gave you 2 excellent choices to go with. Threshold SA series or T series. I happen to not like Solid State as much as tube amps because tubes sound more like music compared to SS. The 2 amps I’m recommending are tube-like sound and extremely good. When I say good, I mean outstanding. Just so you get an idea of where I’m coming from. Your mid level cables should be fine-to-perfect. I like some other amps mentioned but what I like to see in a solid state amp is simplicity and built solid. I know of other amps that sound fantastic too but are built very complex with a ton of internal parts. I feel that the simple, well made SS are my favorites and most reliable. Also, I’m bias that I highly prefer class A amps. If I were you I would not discount older class A amps, 20+ yrs. Some of these are beast and will out live you and me and the next generation. Some just require new power caps and they are good for another 30yrs. The 1st thing I listen for in a SS amp, is it musical and transparent.  Next, does it have detail. Is it refined and does the music flow. Resolution, imaging, soundstaging, etc. I go down the line. If it passes all the things that matter to me, then I feel it’s a killer piece and it’s for me.  You happen to be fortunate that your speaker do not need a lot of power.  Try a Threshold T-100, or T-50.  
I

@chorus

Are the INT-25 and XA25 still in the running?

Different amps, but also wondering if you already reviewed the INT-60 too... or heard one in person somewhere.  

The previous generation Luxman m-600 and m-800 (all class A 30w and 60w respectively) had something that even the newer generation models don’t have in terms of thick class A signature sound and tons of current to punch way above their weight. Might be worth looking into whether they are a good match for your speakers. I compared them to all the Luxman integrateds and preferred them by a significant margin (though they are more similar than different). They also run nicely as monoblocks.

Thanks again for all the ideas. That LTA is one I am quite curious about.
I need to determine whether my speakers can be satisfied with only
a 25 watt Pass or if more power is truly needed.

Keep your eyes peeled for a used Luxman L-590 AX II.

Thats the itch i dont want to scratch.. was on my brain as I listened to the 550ax2 all weekend ... aye corona

http://www.10audio.com/valvet_e2-se.htm

Not much power.....but I bet plenty for 94db speakers at the levels you listen to.

Well, if that the direction you want to go in, SS will be faster and have better dynamics and more control over the music

I'm not ever sure that's the case either. I know of tube amps that are faster than most solid state amps. 'Dynamics' is often a word used to describe distortion, since so often the distortion is most apparent on transients. The ear uses higher ordered harmonics to sense sound pressure, so if that distortion is mostly on the transients (even in small amounts) the reproduction will seem to be more 'dynamic'.

But actual dynamic contrast is a function of the software/media, not the amp!

Rice,

Thank you so much for introducing me to the 10Audio website.
I had never heard of it. I read his Valvet Int. review and now I
want to audition this product. Along the lines of LTA perhaps?
Do you own one? If so please tell me about it.

I spent a lot of time looking to replace my Mcintosh separates which stood me well for almost 20 years, but once I started to listen the newer equipment I realized the MC’s were dated. Finally went above my price range and got the Luxman 590AX II. The sound is night and day on my Totems. Clean, clear, very very slightly warm. Big soundstage. It’s a keeper for a long time. You can go one step lower in power and that should be in your price range. But I just waited till I had the dough for this one. 

So you went SS and preferred the Luxman over the Pass?

Chorus, there is a Fortè Model 4a on eBay now for $650. Class A amp, 50 watts per channel. https://www.ebay.com/itm/114175241726   Exact design as the Threshold “T” series. A killer amp and kicks ass in sound. Highly musical, highly detailed! It is a high recommendation for your system. If you want to spend more money on another amp, I would bet the Fortè would walk all over whatever amp you put it against upward to $4000 and higher.  Lowtubes@gmail.com

Hey I like this thread!

My two cents worth...I have had many amps in a magnestand 1.6/rythmic 12SE sub system. Having no mind of my own I called Mark at Reno Hifi. And asked him what do I need? (Dont you love it?) He said Carlitos either use a Pass 30.8 ( I thought no way) or a Pass 250.8 (its has a class a high bias). I am poor so I went with the Pass 30.8. It has been in my system for 3 years iand is is absolutely wonderful. Its smooth, holographic AND it drives the maggies exceptionally well.

The pass 30.8 is a better amp in comparison to the pass 25 

Blessings 

Carlitos

I like the extra dynamics and bass of the SS Pass but it does burn
a little bit on the top end over time. I adjusted my Tannoy treble settings
downward to help this.

@chorus I missed this earlier; the reason SS is bright is due to distortion. Its not very much, but the ear is keenly sensitive to this type of distortion (higher ordered harmonics) and perceives them as brightness and harshness. For this reason you may find that while you can tone it down a little by simply turning down the tweeter, you can't actually get rid of it entirely since its not due to a frequency response error.

Okay more interesting suggestions, thank you!

Re Forte-yes good sound but too old for me. Not wanting a rehab project
right now , thanks.

Valvet sounds like the LTA product in many ways. I will look for
someone here that owns one. So obscure I doubt my luck though.

Carlitos- You are the guy I have been waiting for! 
So you compared the XA25 to the X 30.8 and preferred the
30.8. Now that is an interesting comparison that so far only
you have done. Thanks.

Deco- I have not heard the INT60 yet. Not sure I need to HP or extra
weight and heat. 

Atmo- I read your comments about a tweeter's Unbearable Harshness of SS and hope you are somehow unaware of a cure. Cables?

So far the brands I am attracted to for further comparison are:

-Luxmann
-Valvet
-LTA

Did I miss anything good?

Look for a Sumo The Nine, a Jim Bongiorno design providing 60W class A. Simply one of the nicest amps I've ever heard and will snap one up if given the chance.

I see Tom8999 is using a Son of Ampzilla II in his system which is also designed by Bongiorno and would be worth considering. I still own the original GAS Son of Ampzilla which must be over 40 years old and is in my system now but has been rebuilt.

I recommend a recap and general look-over by a competent and sympathetic technician. The internal wiring should be replaced with solid core OCC wire and input / output sockets replaced with the very best available. Low-mass offerings from Furutech and WBT come to mind. Must replace the IEC socket too.

I say 'sympathetic' because you will always get the know-all tech who will claim assertively with a snigger that it will make no difference and leave you with a rude and dismissive 'well it's your money'.

Have heard it drive electostats, magneplanars and a variety of boxes with ease.  It drove my Tannoy MG 15 Golds with aplomb. You could also lookout for an early Threshold or a Spread Spectrum Technologies which was Bongiorno's last before he died.

Another plug for the Luxman L-590AX. (newest version is the L-590AXII).
I haven't owned near the different pieces as most here, but the thing is stellar, to my ears. I have never for a second regretted the purchase.

Valvet E2 SE.

Supposed to be phenomenal. 10 audio says it's fantastic.
$2,990 new.

Hi have had Bat Rex tube mono and along with Bat Vk 600 se ampsMoved to Pass Xa160.5 ...found current amps Bhk hybrid 300 best sound of amps..Running Bat vk53 se pre amp Speakers are Apogee diva’ s With new ribbons etc


 

Every time I hear Class A, I automatically think Pass Labs. Just saying 

I bought two Schiit Aegir Monoblocks for less than the price I paid for a pair of speaker cables..  Class A sound using a new continuity circuit designed in house..  tube like attributes without the Tubes ! 
Why spend more ?  You should hear how good these sound..  Made in the USA too..  
I spent a lot of money over the years To learn that you don’t need to spend a lot of money To get a great sound! 

Atmo- I read your comments about a tweeter's Unbearable Harshness of SS and hope you are somehow unaware of a cure. Cables?

@chorus I suspect you have a typo here.

The brightness is caused by distortion and because its in the amp, probably not something you can get rid of with an equalizer. It might be possible to use a ZOBEL network on the speaker itself, targeting the band of brightness, but since its caused by distortion the band is a bit of a moving target depending on the music and how loud its being played.


IMO you're best off going with an amplifier that doesn't exhibit brightness to start with! In the solid state world, that's a really tall order; a really short list. Since your speakers are easy to drive if I had to go with solid state I would be looking at an amplifier that runs no feedback such as Ayre or First Watt. If not available or rejected for some reason, a zero feedback class D amp is worth looking at too.

Atm,

Yes a typo, my bad. 

So Zero feedback-Ayre, First Watt will help dodge the dreaded
ear burn.
What about the XA25 ?