$$$Sensitive Speakers with $$Amps?


I've read a recent thread, and a Six Moons review for recommending certain amps who's price tag falls short of the subject loudspeakers. For example, Red Wine Audio 15 with Rethm Maarga speakers.

My area of focus is with sensitive speakers being driven by low-watt amps. Are there really super values out there for these type of amplifiers, or do the typical spending rules apply?
kennythekey
spatial presentation which won me over. Not as haunting, but intimate, open, and refreshing, were the Voxativ Ampeggios I heard in Montreal 2011.


~~~~~~~~~~~~~~~~~~~
I keep running across good things said of the Voxativ, 
My comments on their performance will be straight up. 
The good and the bad. 
Stay tuned. 
My area of focus is with sensitive speakers being driven by low-watt amps. Are there really super values out there for these type of amplifiers, or do the typical spending rules apply?kennythekey


~~~~~~~~~~~~~~~~~~
Well there area  few issues with SET amps,
They are not my cup of tea. 
But I LOVE if not ADORE high sens speakers.
 When my high sens speakers are ordered next month, my plans are to set up 3 amplifiers.
KT88 100 watter
EL34/35ish watter
SET 250 tube, not sure the wattage,  maybe 25ish. 
My bet is the  EL34/Dynaco Mark4 DIY amp will come out by a slim margin as the winner.
IMHO The EL34 may just be the most perfect tube for high sens speakers. 
We will see.
Will the 100 watt  KT88 work out? 
Ancedotally I've been told, yes it will be acceptable.
Alkso, try out the sleeper and giant killer of the year amp, the TBI Millenia. Their is a review of this at TNT audio here on the net. When you hook up a 24V battery system to it, you will hear more detail than you have ever heard before, while staying very musical.

A friend of mine has the Rethm Trishna's and he prefers the TBI over his MiniWatt N3 by a fairly large margin.
Thanks David.

I've been living with conventional mid-nineties box speakers, well, since the mid-nineties. I have gotten years of enjoyment from them. There were multiple rooms with Dadalus speakers at the RMAF 2010 show where I also heard the Horning and Aspara speakers that Jeff was demonstrating.

I'm not a classic horn person, as they don't quite fit my ear. I try, and try again, but I can't fall in love with Klipsch, for example, and Jeff's Aspara offering did not quite do it for me either. I also struggled with "all" the box speaker offerings at the show. I want to blame the rooms somewhat, but my disappointment remained consistent.

For whatever reason (hybrid?), I fell for the Hornings. I must admit that Jeff had a large suite and he's a wizard at setup. Still, I can't get that sound out of my head while all the other sounds at the show have long faded. It was the haunting and intimate spatial presentation which won me over. Not as haunting, but intimate, open, and refreshing, were the Voxativ Ampeggios I heard in Montreal 2011. Equally refreshing in Montreal were Devore's Orangutans. However, with all of these choices, I didn't miss LF extension as much with the Hornings.

I'd like to get back to amplifiers, and have added the < $4K Almarro 318B to my list. Here is the revised list, so far:

Loudspeakers:

Horning Aristoteles
Rethm Maarga

Amplifiers:
Note: I realize some models will be integrated, so a plus IMO.

MiniWatt N3
Red Wine Audio Signature 15
Yamamoto A-08S
Déjà Vu 2A3 (Under $4K?)
Audioprojekte CA10
Traformatic Aries
Triode TRV-A300SE
Almarro 318B
It seems to make good , hard nosed economic sense, to go for High sensitivity speakers and low powered amps. High sensitivity speakers don't need to cost more, the cost maybe is reduced base output. High output, particularly with tubes, cost money, at least for reasonable quality.

I agree amp noise is an issue with plus 100db sensitivity horns, but personally, I have never liked horns. The sweetspot for me, is mid 90's, conventional box speakers. They sound great with as little as 10watts, but 20 seems a better, all round choice. My Dadalus DA-RMa speakers sound wonderful with the 20watt Ayon Spark and cheaper options like the Almarro 318B
Trelja,

Well, I haven't heard the Aristoteles because they haven't been at the RMAF show in Denver when I've gone, but got to hear their big brother the Eufrodites. I also have not heard the Rethm Maargas, so it makes sense to go to NY to hear both.

I'm sure that Jeff and Gideon can recommend amplifiers that won't break the bank.

Thanks for the invite to PA, but it will most likely be a short trip. My room is brick, plaster, and hardwood floors, so is that what you also have?

My wife and I were in NY (Queens) for ten days in the old neighborhood. Unfortunately, we had to take care of family business and could not get around, however, we feasted on local Italian every night. Yum.
Kenneythekey, I'm impressed in the most incredible way by your willingness to travel all the way to the East Coast to hear the Hornings. Indeed, the bravo goes not to me, but you! It's exactly THAT kind of passion that makes this hobby so wonderful.

With RMAF so close, September might not fit the plans of either you or Jeff. But if you can swing it, the annual Feast of San Gennaro http://www.sangennaro.org/ is a very short walk, and something not to be missed. After San Francisco (never visited, but it holds the reputation), New York probably has the most interesting Chinatown in the country, and also sits right there. Still, the sight of the Brooklyn bridge right there at Jeff's place will likely move you in a big way.

Since you'll be out this way, if you care to travel 1.5 - 2 hours south to Philadelphia, you're welcome to give my Hornings a listen as well. Since our rooms are so different (brick/hard floor vs. drywall/carpet), the sonic presentation would likely reflect that.

Mapman, I'm not a low volume guy, but understand that's more the rule than the exception. To answer your other question, with the backloaded horns I have been around, yes, some SETs can do more volume than the more familiar push-pull amplifier.

Again, a sort of "coupling" that transcends wpc ratings may come into play. We know it's not electrical impedance in this case, but I don't think the word "impedance" in a different sense of the word misses the mark by far.

Another way to picture it could be the ability to propel the air that exists through the long length of the exponentially expanding horn forcefully enough so that it meaningfully adds to the impulse propelled from the surface of the driver itself. Obviously, I haven't worked it all out, and I've yet to meet someone who can explain it to me. It might be when comparing SET, PP, and OTL amplification, we're dealing with something like the whip versus the club; both of them powerful, but of a profoundly different nature.
".. its nice to have some dynamic range available, even if it does not get used all that much."

Not just dynamic range (difference between loudest and lowest levels) but headroom in general to go loud as needed even if the dynamic range is compressed, as it is in many if not most popular recordings out there these days.

Just watch your ears. Too much exposure to SPLs over mid 80's or so is generally acknowledged to damage hearing incrementally over time.

High efficiency speakers combined with high power amps might be the closest thing in audio to a weapon of mass destruction. Especially when accidents happen ( and they do happen). So be careful....

I was glad to hear that one agoner I know of moved to a more flea powered tube amp from a 500w/ch Class D shortly after adapting a pair of Avantgardes.
05-18-12: Atmasphere
... its nice to have some dynamic range available, even if it does not get used all that much.
One of the widest dynamic range recordings in my collection (although there are many others that are close) is the Sheffield Labs recording of Prokofiev's "Romeo and Juliet," conducted by Erich Leinsdorf. Out of curiosity, a while back I examined its waveforms on a computer, using an audio editing program. The difference in volume between the loudest notes and the softest notes was around 55 db!

On that recording, and quite a few other classical symphonic pieces I have on high quality labels that tend to use minimal compression, I frequently measure brief peaks at my listening position in the 100 to 105 db area, using a Radio Shack digital SPL meter, although the average level is by no means particularly loud.

Those peaks are not nearly as loud, btw, as those I heard when I once listened from the very front row at Tanglewood to the Boston Symphony Orchestra performing that same Prokofiev work. My guess is that the peaks easily reached 115 db.

Best regards,
-- Al
Charles1dad, its not like I listen to those levels all the time! But there are certain LPs, that in order to sound life-like, have to be allowed to do what the composer and musicians had in mind.

The Verdi Requiem (RCA Soria edition), side one track 2, is an example. The music goes from ppp to ffff (for those of you not into music, very very quiet to as loud as can be played) and as far as I can make out, the LP is not compressed. It will bring most stereos to their knees very quickly! Its just not convincing when the system is playing the quiet portions at the right level and then craps out/compresses/gets harsh when the music demands it. So its nice to have some dynamic range available, even if it does not get used all that much.

Here's couple of others:
Decca/London Das Reingold (Solti cond.) side 6. Amazing. (I'm not much of an opera fan but I make an exception for Wagner.)
Black Sabbath Paranoid Vertigo 'white Label' UK edition. Astonishingly well-recorded. The energy in the grooves is un-playable on many systems.

Joe, seriously, we've not been sitting on our hands in the last 8 years. Get that M-60 in here- I think you will be pleasantly surprised... Now I am wondering about this horn/transmission thing. As you know I had some of Bud's speakers as well (still have his big subwoofer) and our amps have always found them a very friendly load. But I've had a lot of horns too and have found them to be friendly loads too. But you have been very consistent in your comments about rear horn loading, which flies in the face of our experience/feedback. So I am wondering if there is something in particular about the speaker model that you have or what. There's not yet enough data to be conclusive.
Thanks, Trelja.

Bravo, a good dosing of tangible results through hands-on research! Well done.

As I quickly and loosely threw a number of amplifier contenders into a heap, it sounds like you might be able to help me discard and/or re-sort the list to better match the two and possibly additional speaker models.

As with many audiophiles, I love music without an engineering degree, so my ears tell all. Your contribution, however, makes me wish I had at least finished my correspondence course with the Cleveland Institute of Electronics. Funny, I got to the part about vacuum tubes and threw my hands up. Too bad, it was back in the seventies and I had no one to hold my hand, like on AudiogoN!

Seriously, this forum thread is not all about me. Hopefully, it can be used as some small reference to others of what types of low-watt amps match up nicely with types of HE speakers. A plus, and the part that is related to me at this time, is finding lower cost wonders to match up with my speakers of interest.

I live in Colorado, so I have access to RMAF. This is where I met Jeff (HWS) who’s a great guy and my main dealer of the last three years. I also grew up in NYC and worked downtown, so I am very familiar with the surroundings.

Again, thank you for your help and commentary.
Kenny
Trelja,
Very nice and interesting post!
There are things that happen with audio that are just hard to explain(and sometimes hard for some to except)I was a happy owner of a very good PP tube amplifier(100 watt UL and 60 watt in triode). Along comes an eight watt 300b SET and everything changed,there`s no going back.Interstingly my SET amp also uses an interstage transformer rather than coupling capacitors(not sure of the significance).
Regards,
Trelja,

Its not clear to me what is the criteria by which you assess the SET versus push pull with the back-loaded horns.

At what volumes are you comparing? Are you saying the SETs go both louder and clearer than the push-pulls? How about at lower volumes?

How many combos of sets and push pull amps with back-loaded horns have you tested and observed this behavior with? Same results with each?

Thanks.
Kennythekey, in what part of the country are you located?

Since you have the motivation to visit Jeff Catalano, I fully encourage you to do so. You'll have an absolute blast! Jeff's a great guy, representing some of the more interesting yet least encountered equipment. His place, literally in the shadow of the Brooklyn Bridge, is something of a historical landmark, filled with more records than you'll believe.

Though difficult for me to explain in objective terms, something certainly exists with both backloaded horns and transmission line bass alignments in that they behave in a more complex pattern in terms of the load they present to a partnering amplifier than do sealed, ported, and front loaded horn loudspeakers; all those operating in a far more simple way. Then again, it should appear logical that what happens after the electrical impulse excites a driver's voice coil will be different as the driver's backwave has to travel such an incredibly far distance in comparison. The simple, electrical, numbers living on a stat sheet fail to capture this phenomenon. At any rate, let us understand that how the amplifier interfaces with the loudspeaker will determine how effectively, or not, that air mass propels down the labyrinth.

As Bud Fried stressed, a backloaded horn and a true transmission line are the exact opposite of one another. In simple terms, as the name implies, the area of the horn increases exponentially in size as we traverse it, whereas the transmission line decreases exponentially.

My experience shows that some amplifier topologies work better with some loudspeaker alignments than others. Representing a company producing a wide range of amplifiers allowed me to play in a way where differences in parts and the designer's approach canceled out. By that I mean, the amplifiers used parts from the same manufacturer and type, and the amplifier circuitry would be shared across differing products. Obviously, when comparing a push-pull pentode design to an SET, you would find the expected disparities. However, when comparing a 211 and 845 SET or 2A3 and 300B PSE or push-pull, we were dealing with almost identical product.

What initially surprised me was that the company's very powerful 78 wpc push-pull triode/pentode switchable amplifiers paled in comparison to the ability to put power into a backloaded horn next to their modestly powered 15 wpc 211 and 28 wpc SET. The 300B 8 wpc SET and 16 wpc PSE wound up closer to the 211. Now, who would ever believe that an SET could outmuscle a push-pull amp in a drag race? Yet, across the speakers of three different companies, the trend held up. Strange to see, but it actually came across as if the PP amps felt like a runner or bicyclist struggling for air when climbing a steep hill. These amps just could not get over the hump. This demonstrated there really is something to the SET phenomenon that those who denigrate their low power on paper have not yet realized. In somewhat of an analogy between tube and solid state, I believe the SET kind of power is actually different in a way we have thus far failed to be able to measure.

The transmission lines displayed conventional (and expected) performance.

Again, the OTL amplifiers we used (not only Atma Sphere - note: the A/S were 2004 and 2008 vintage) behaved the way I described in an earlier post. One big surprise that I didn't mention, even with the nominal 4 (dipping to 2.3) ohm load of one of the true TLs, the OTL amplifiers, even the 30 wpc Atma Sphere S30, outshined more powerful transformer coupled tube amps in virtually every case. Of course, just like people I know who power their B&W and older Wilson (newer are much better) speakers with OTL amplification, just because it's done, doesn't mean it's good.

In the end, as the saying goes, it's horses for courses...
The best amplifier I have ever owned (and not the most expensive) is a pair of Audio Note Kits Interstage Monoblocks running 300b's.

Completely, and absolutely silent on my 100+ db effecient horns.

The interstage transformer relaces the more common coupling capacitor that tends to color the sound and degrade the resolution. Still under 5k built by a professional, about the best deal out there in my opinion.
Hi Atmasphere,
Wow ,you do listen at higher sound levels then most I`d imagine.Just purely out of curiosity do you have concerns about potential hearing loss at those listening levels?Last night I attended a jazz show featuring a quartet at our local Steinway Piano Gallery and took my extech sound meter along. This group consisted of an alto sax,piano,acoustic bass and drum kit. I was about30- 35 feet from the stage and sound levels C weighted were in the mid 80s db range with occasional drums peak to 95-97db. That level was 'plenty' loud enough yet very comfortable(just beautiful tone and music) no need to play any louder IMO(you could hear everthing!). Those instruments be could played at a much louder level(but why?) 105 db sure is a loud level, but as is always the case, to each their own.
Regards,
Charles1dad, I think I did that last post pretty poorly! I meant to confirm most of Joe's comments. I was editing my post and deleted that part, then forgot about it. What I was commenting on really only applied to the M-60s he is using, which are pretty old (if I recall right his set was built about 1997).

I do tend to play things louder than most audiophiles do though, if my experience at shows means anything. Its not uncommon at home to listen at 105db or more (my system is very relaxed at those volumes); my 300b amp won't let that happen, although it sounds great at lower volumes.
Thanks, Almarg.
I prefer to list only new equipment for the purpose of this thread, and because I only purchase new equipment with the exception of cables.

Updated List:

Loudspeakers:

Horning Aristoteles
Rethm Maarga

Amplifiers:
Note: I realize some models will be integrated, so a plus IMO. I put a few on the list that I know about.

MiniWatt N3
Red Wine Audio Signature 15
Yamamoto (Model? Under $4K?)
Déjà Vu 2A3 (Under $4K?)
Audioprojekte CA10
FirstWatt SIT (Under $4K?)
Atma-Sphere (Any under $4K?)
Traformatic Aries
VAC Renaissance (I can’t find this?)
The VAC Renaissance power amplifiers were superseded by newer models some years ago, but you'll find the 30/30 model (32 watts/channel) occasionally offered for sale used, generally for a bit more than $3K.

The 65 watt/channel 70/70 model also appears occasionally, generally in the $4K to $5.5K area.

The manual for the 30/30 is here, and for the 70/70 here.

Both are extremely heavy, which is reflective of the high standards to which they are designed. The 70/70 MkIII model (that I have) sold for about $14K when new, roughly around a dozen years ago I believe.

Regards,
-- Al
Like Trelja, I hold onto my equipment for a long time, so it’s nice to have updates available. That’s always a plus.

I would like to create a list of possible candidates for low-cost/low-watt amps, and set a range for cost. I will not rule out the MiniWatt, but I’m thinking the low end should start at $1,500. I would also like to set the high end at $4K, because I know that Sam Kim can build me an amp for that, and it would be his best design for my speaker of choice.

I would also like to add to my sensitive loudspeaker list, but keep any additions within the range of the Maarga and Aristoteles ($8,500 - $11,000).

Loudspeakers:

Horning Aristoteles
Rethm Maarga

Amplifiers:
Note: I realize some models will be integrated, so a plus IMO. I put a few on the list that I know about.

MiniWatt N3
Red Wine Audio Signature 15
Yamamoto (Model? Under $4K?)
Déjà Vu 2A3 (Under $4K?)
VAC Renaissance (I can’t find this?)
Audioprojekte CA10
FirstWatt SIT (Under $4K?)
Atma-Sphere (Any under $4K?)
Traformatic Aries
Sam's Audio Labs
Atmasphere,
Apparently the many who`ve heard the Horning-Tron 8 watt combo would disagree with you and your stated limitations.
Trelja's experience flies in the face of what our other Horning customers report, but it might have something to do with Joe's amps being 12-15 years old without any updates (its clearly time, Joe- you know the warranty reactivates with the update, right?). Most of our Horning customers have much newer amps.

From what I can make out on the Horning website, the specs and design notes confirm what our customers report: the speaker is an easy load.

The efficiency is what I would call verging on high efficiency. 96-100 db or so depending on the model- you will want some power with this speaker, a 7 watt amp will not do it unless you are listening near field in a very small room, at least if you expect the system to play anything- Black Sabbath to string quartets. My speakers at home are 98 db and I find that I do appreciate having more power, 60 watts is nice, very hard to clip. My room is 17' x 21' with moderate damping and solid walls.
Charles,

I've heard the Horning Eufrodites driven by the Tron Telstar 211 SE. The Eufrodites use four eight inch woofers where the Aristoteles just have two, so they were recommended for my room size.

I think a trip to NY to hear both the Horning and Rethm on the same day would be smart.
This is excellent information, and for my smallish room the Aristoteles were recommended by Jeff (HWS). Likewise, I was considering the Maargas as a possible contender, but I would have to travel to NY to hear them.

The Aristotels use two rear eight inch woofers in push-pull.
Kenny are the Hornings you`re interested in the same as Trelja`s? I ask as you heard the Horning driven by the 8 watt 300B Tron SET and found it to your liking very much.Perhaps there`re different woofer arrangements among the various Horning models.My speakers have two 10" woofers per side and are driven very well with my 8 watt SET.I realize this ability to drive is dependent on the particular speaker and certainly which SET amp one is using. Some just have stiffer power supplies and bigger/better transformers than others.I don`t doubt the ability of a good quality 845 amplifier to work well at all.
Regards,
My Horning speakers don't do so well with SET 300B, or even PSE, as the dual 12" woofers never get the power they're looking for. I've long wanted to try the 300B based push-pull VAC Renaissance products with them, and see what comes of that.

Rethm speakers do mate in an especially synergistic way with 300B SET amps. The Rethms don't ask the amp to produce the lowest frequencies ala either having no driver that can produce them, or those that do have an onboard solid state amplifier to handle the responsibility.

The 845 and 211 SET amps I've owned all did superbly with backloaded horns. Regardless of specs, no amps rivaled their ability to put power into that type of horn.

My Atma Sphere M60s and a friend's S30 don't couple well with the backloaded horns we've tried with them. Mate the Atmas with the antithesis of that alignment, a true transmission line, and you'll not find better amplification. Also, after hearing the Miyajima OTL with Quad ESL57 in NYC last month, the notorious and wonderful synergy of the electrostatic/OTL topologies comes across clearly.
Atmasphere,
You are right of course, as your amps have stood the test of time and are highly regarded. No debate there, as some expensive amps do deliver the goods and sound superior. This, probably relates to the quality of parts used that cost a pretty penny, but provide the final percentage of return. I understand, and thought I relayed the value of spending the extra bucks with my reference to the $40K Tron that I love. I know that you have far less expensive designs.

It's an intersting hobby, and for some of us we enjoy finding less expensive solutions that excel to fit our personal high expectations and budgets of what's wonderful. For example, Sam Kim does not install Auricaps or the like. Instead, he cuts open different runs of quality capacitors and he knows by inspection, which ones will sound the best. This is what does it for me, because I'm a retired Locksmith who doesn't have unlimited funds. However, there are reviewers who expect the quality of parts to be there. This is why I rely on all of you for quality feedback.
Thanks Charles! Yes, research and patience.

I don't know if this thread will hold up, but it would be great if Horning/Rethm owners could chime in with their own amplifier solutions. Or, if we got more contenders for lower cost/low-watt amplifiers regardless of the high sensitivity speaker type and/or brand.

That would surely help with my research and definitely my patience.

It seems that most boutique dealers are located on the E. & W. Coasts, making it difficult for this Colorado guy to hear stuff up close and personal...Except for RMAF, which is not so up close and personal.

My goal, is to get a low-watt Sam Kim amp and compare it to a few winners that I've researched (I consider this research), and then pick my keeper.
Kenny with the Horning you`re lucky in that you have many choices available. OTL, DHT tubes as SET or PP design,low power SS(in class A) etc. Just with 300b amps alone there`re so many good choices for less than silly money.Many Horning owners seem to do quite well with 8-10 watts of power. Of course the transformer and power supply can vary significantly at the same power rating.Based on what your priorities are it seems a DHT(2A3,300b, 845 etc)either as SET or PP will give you what you want.OTL is a different sound and certainly has it supporters also.

It would be ideal if you could compare some SET and OTL amplifiers with your speaker of choice and simply hear for yourself.I`m confident you`ll find exactly what you want with some research and patience, I sure did.
Regards,
Our amps only have one stage of gain. Hard to get simpler than that. In general its been my impression that cost is less important than the simple fact that some amps sound more like music than others. So my answer is now 'depends' as there are expensive amps that do deliver.
Hi Charles,

I am welcoming suggestions and thank you for yours. I will keep the First Watt on the back burner.

Single drivers and simple circuits seem to go hand-in-hand. There are only a handful of different ways to design simple amplifier circuits. One can complicate the design by adding tricks to make their's unique, but that's getting away from the purity of sound IMO.

This tells me that great sounding low-watt amplifiers can be built inexpensively and this has already been revealed. Other things that I've come to believe, for example, is that point-to-point wiring is ultimately superior to circuit board wiring. Again, this is my opinion. However, good looks and other features drive up the costs for boutique designs. I don't want an ugly duckling, but a compromise seems reasonable.

I like to challenge what I've become comfortable with. When I get my speakers of choice, I will use my current Sam Kim amp to see how it does for noise and SQ. Sam can also build me a low-watt design, but a 300b or 845 may not be Sam's choice. This is why I'm seeking everyone's help, so I have more viable options and can narrow down my listening when I'm ready to get serious.
Hi Kenny,
I believe you`re moving in the right direction and there`ll be no looking back. The Hornings and Rethms are both very good choices. I agree with other posts above in that a good 300b or 845 amplifier(is a used amplifier a consideration?) will certainly provide the sound you seek(life like realism not hifi) I understand the Krell system example you gave above(phony/sterile ultra black background rather than live sense of ambience and background presence). If you do go SS have you considered the First Watt amplifiers, particularly the new SIT version?
Regards,
Nope very little to lose on the MiniWatt. I use one with Psvanes (Grade A from Grant Fidelity) in my bedroom system, which had HornShoppe Horns.

ALO Audio also sells these and offers some upgrade tube packages as well.

I have also heard that their are sonic improvements to be had from bypassing the volume control and running the N3 via a preamp, but I haven't gotten around to doing that yet.
Roscoe,

THe miniwatt looks very interesting! A nice minimalist design with volume control even and very reasonable cost. Even available through Amazon. It would be a nice fit for a third system I am looking to try sometime built around HE speakers. Looks like not much to lose in trying.
Thank you everyone for your insight and personal experiences.

Living in the more conventional world of multi-driver solutions, my belief system for amplifiers was that you get what you pay for. This was unraveled somewhat with the amp Sam Kim built for me. For me, a step up in SQ for less money.

For someone who loves the Horning sound, I was taken at a show when the amp was switched to the $3,000 SS Audioprojekte CA10. I realize, if I spent more time comparing the Audioprojekte against the default Tron, I would probably pick the Tron. Still, the rule of diminishing returns seemed to almost disappear when compared to differences with other types of audio components. I consider the CA10 a super value, and it was the reason I started to investigate the subject of this thread.

I agree and understand that the amplifier must be dead quiet in order to achieve the sound that we seek. At the same time, I don't want to give up the "life" that great tube amps fill into that dark space. For example, I was put off by a $100K Krell system with the quietest and darkest of backgrounds. Add to that great pinpoint imaging, but with a flaw. The players floated in their own bubbles with no life (air) between them. This is my own opinion, but I became bored as the sound seemed cold and uninvolving.

Okay, probably by now you know what I like and prefer. Additionally, I have a smallish room (16 X 14') and require an intimate sound. Even so, by gravitating to the Hornings and Rethms it's also obvious that I require some bass. The woofers of the Rethm are powered, but the Horning woofers are not. Perhaps, this makes the Rethms easier to drive with a more cost-effective solution.

While Sam Kim's amp is brilliant, and he can build me any push-pull triode that I can think of, I'm not sure about the needed silent background for these highly revealing drivers.
A shockingly inexpensive tube amp that is also surprisingly quiet is the MiniWatt N3. Quieter than much more expensive tube amps I have tried. And only 3 tubes to roll, making it cheaper to try out tubes like Psvanes (which I love in mine). Might be a great back-up amp for the speakers you are interested in.
My other observation regarding amps specifically with good HE speakers is that listening to music with very HE speakers, like Avantgarde say, is like listening to music under a microscope. You will hear everything, both good, bad, noise etc. THe sound of tube amps in particular can vary widely but the best sounding tube amps to me are also the ones that sound most like the good SS amps I have heard. And the best ones I have heard accordingly tend to be very expensive (VAC, ARC, Audio Note, etc.)! HE speakers are of particular value with tube amps in that the efficiency helps keep power needs minimal which can help keep tube amp cost down as well. A good SET may be all that is needed, but even those can get somewhat pricey for a really good one.

I am very interested in finding the good bargain SETs out there as well.

I have two pieces of tube gear, a DAC and a pre-amp.

The DAC is an overachiever for its very modest cost so I was willing to take a chance and go with a smaller vendor that seemed to receive universal rave reviews and that has worked out exceptionally well.

The pre-amp, an Audio Research, cost a good bit more but is still modest by some audiophile standards. For the bigger investment, especially first time out, I felt best going with a larger known entity like ARC not just becasue the gear sounds good but in hope of good customer service when needed, replacement tubes, etc. Maintaining the ARC is not horrible but it is not cheap (good QUIET tubes are EXPENSIVE). As much as I like the tube pre-amp, I still find myself thinking that when the day comes to replace it, I will try to go back to a good SS pre-amp in that I am not one who gets any enjoyment out of maintaining gear. I just want it to perform consistently well so I can listen to it.
AMps must always be matched to speakers for best results.

In the case of high sensitivity speakers, like horns, my first concern would be noise levels. If the amp is not dead quiet, chances are you will hear noise. I would focus on assuring the amp is quiet today and also reliable so that it will stay that way.

Tube amps work well and sound lovely with most HE speakers, but noise levels are more problematic with tubes in general. Tubes must be replaced periodically as noise levels creep in with age.

So I would be wary of inexpensive tube amps that might be more likely to have or develop noise issues, but I am also confident that inexpensive good ones that are also quiet are out there.

A lot has to do with expectations regarding noise levels and what bugs you. I prefer dead quiet background but have learned to live with marginally higher background hiss noise levels with my modest tube gear. I cannot tolerate other kinds of noise or easily audible background hiss when I listen because I was not brought up on tubes and not used to that kind of thing. So it all depends.
I own a pair of Hornings, the product previous to the Aristoteles, that I use in my second system. Given their resolution, the quality of amplification certainly does make a difference.

My opinion regarding amps that retail for $20K - 40K is they are often boutique products and/or produced in countries (often, Europe or Japan) where a price premium gets applied. While you don't need to break the bank to drive them, you don't want to aim too low, either. And, as a surprise to some, due to the onboard woofers, you want to give the Hornings some power as well, more than you might consider otherwise. You don't need to go overboard, but in order to not have them come across as unbalanced in a bright way, you don't want something limpwristed.

Push pull tubes seem to do best with them. Triodes generally are better than pentodes, though my Jadis DA60 and Dynaco ST70 marry well with them, for whatever reason, my Jadis JOR and DA30 not so good. I own a cheap Chinese 6AS7G push-pull integrated from Jas that also makes me happy. Best of all was a Deja Vu 15 wpc push-pull 2A3.

I also have spent a fair amount of time with Jacob George of Rethm. Should you go in that direction, you can away with less power than the Hornings, due to either not having to drive any woofers or having them powered for you. Still, aim for quality, as the Rethms will reflect your decision there.
Are there really super values out there for these type of amplifiers, or do the typical spending rules apply?

The short answer is yes. Your job is to go out and find the really super values.
I think Jaybo is correct to question your speaker choice. Why not go for a full horn system and skip the in-between step of full-range driver back loaded horn?

The Red Wine Audio Signature 30.2 spent some time in my systems (a Jordan full range and a full horn system). It has a great sound in its own right, but is certainly not in the same league as a proper 300b amplifier.

For < 5k you can have a Yamamoto that will certainly sound far better than the Redwine, and I do not mean any disrespect to Vinnie, he makes a good product, but there are limits to solid state sound.
The Hornings are very sophisticated speakers and will benefit from a smooth and rich and transparent amplifiers with big sound stage and good front to back layering. I am thinking tubes, 300B 845's. Bigger tubes seem to have a bigger sound which I prefer. We carry Sophia Electric and they make some very nice sounding 300B amplifiers as well as 845 mono blocks. 'Just a plug here."
Jaybo,
My questions aren't so much about choice of speakers as about if there are relatively low-watt amps that can equal the SQ of much more expensive choices.

I am heading in the direction of sensitive speakers in the 96 to 99dB range, but my current amp is a 6550 35-watter.

I happen to love the sound of the Hornings and have listened to many speakers of different types from multiple shows. The Horning sound is still my personal favorite after three years of listening. However, I always hear the Hornings paired up with $20K to $40K amps. There also seems to be a movement away from Lowther drivers and I got caught up in threads and reviews about the ex-Lowther-based Rethm speakers. I have not heard these yet.

I was at the 2011 show in Montreal where I heard the Voxativ Amppegio speakers which caught my attention. For me, those fit my ears pretty well. I would find out that these cost $30K, so that wasn't going to happen. After finding out that these speakers received Stereophile's Product of the Year for 2011, I read a review in Six Moons where the Rethm Maargas were preferred over the Voxativ in a head-to-head listen.

In the Six Moons article, the Red Wine Audio Signature 15 integrated amplifier was claimed to be an excellent match for driving the Rethm driver. As this amplifier is only $1,500, I became curious if others out there have had excellent results with lower-cost/low-watt designs.

I don't think my point was very clear, so I didn't mean the different costs of tube power.

If I'm looking for a low power amp to drive a pair of Horning Aristoteles ($11K) or Rethm Maarga loudspeakers ($8.5K), for example, am I smart by going with a Red Wine Audio 15 (15 watts = $1,500) or a Tron Telstar (12 watts = $40,000)?

I understand diminishing returns, but the recommendations that I've read about seem to support lower cost super value solutions. I'm trying to find out if this is BS, or if SQ value is for real in the low power amplifier market.
The short answer is yes. If your speaker is high efficiency, you can get by with less power. Tube power in particular is expensive so this can have a huge effect on the price of the amp.