What is missing here?

For an 87dB speaker, 8 watts will give you 96dB at 1 meter. Pretty loud.
If you're buying a 300B amp, you'd have to have done some research. 
Why attack low-powered amps rather than inefficient speakers? ;-)

daveyf:

Except, nowhere ( except in the specs section) does it mention that this amp is limited to 9Watts/Ch!!

I see. So the whole specs section is "nowhere"? And here I was thinking I must be the most derisive of anyone here when it comes to specs. But even I am not going to try and say they don't exist, when there is a whole section devoted to them. A man's got to know his limitations. You win.  

PS- Aren't all amps "limited" to the power they are able to produce?

@millercarbon  The specs section is not really where most readers are going to look that closely, at least IMO. The information on the output is not highlighted in any way in the spec section. Like I stated, the extremely low output is not mentioned anywhere in the body of the review. 

@noromance  How many times have you utilized a 9 watt amp in your system with 87db speakers? I have heard a number of speakers with 87db efficiency that also drop down to below 2ohms, try driving these with a 9watt/ch amp. 

@daveyf I used run a Class D T amp which has about 3 watts! In fairness, it didn't crank well. It is remiss not to include the output in the specs. Maybe they forgot. Perhaps AS assumes anyone who knows their stuff would know the 300B in SE mode only does 8 watts!

daveyf

... how many casual listeners who read this article will realize the extreme limitations that this amp comes with?

The limitation is noted in the article, as you've acknowledged.

I don't think "casual listeners" are likely to be reading Absolute Sound, and the magazine is written and edited for its audience. And I certainly don't think "casual listeners" are likely to even consider a $15K 300B tube amplifier.

Just another product for the money-to-burn crowd! 

If you had told me the price up front I could have quoted the ending pretty much word for word without ever reading the review,though it is missing the comparison to an even more expensive amp that was much better overall...

Nine watts per channel is about right for a single-ended 300b amp.  I would actually be more comfortable with one rated at a LOWER output, assuming that the lower rating means that the designer is intentionally not pushing the output tubes very hard.  Tubes last dramatically longer when they are driven gently.

The thing is, if you want to get the most out of an SET, the speaker needs to be so efficient that the amp is never asked to make more than about 20-25% of full power. Otherwise higher ordered harmonics start to show up on transients, causing the amp to sound 'dynamic' since the ear uses those harmonics to sense sound pressure. So this comment is problematic:

For an 87dB speaker, 8 watts will give you 96dB at 1 meter. Pretty loud.
If you're buying a 300B amp, you'd have to have done some research.
Why attack low-powered amps rather than inefficient speakers? ;-)

because you really don't want to run the amp to full power. Put another way, to get that same sound pressure properly (keeping the amp power to 20-25%), you would need a speaker that is about 93-94dB.


Of course, a 7 watt SET (a 300b won't make 9 watts unless class A2) struggles to have full bandwidth due to how severely the output transformer limits bandwidth as the power is increased. This is why the 2A3 (2-3 watts) is considered a 'better' sounding tube and the type 45 (0.75 watts) even better than that. The less practical SETs become, the better they sound! Of course, the speakers needed for such amps need considerably more efficiency and so bass becomes a problem...

@atmasphere  Thanks Ralph. Your post explains a lot and is certainly very instructive. Apparently the amp has 10% distortion at 9watts. I would have to believe that this is audible. Therefore, a match to the most efficient speakers one could find would seem to be mandatory. Probably only a match to a horn design would be indicated...leading to the other issues you mention.
None of this is discussed in the review, I have to question why?

None of this is discussed in the review, I have to question why?

No idea- best to ask the reviewer. IMO/IME its a pretty important (might have wound up edited out) omission!

Daveyf, I think you are absolutely right. In medical speak it is a drug looking for an indication. As a lover of all genres of music an amp like that is worthless. If you had horns and only listened to string quartets ....... maybe. Nine Inch Nails on ESLs with 4 subwoofers? Forget it buddy. You might as well fry your toenails. There is never such a thing as too much headroom. In my experience very powerful amps (200 watts and up) have an effortless character that few smaller amps can match and this is speaker independent. I look at these little tube amps in curiosity only. 

@mijostyn  Agreed and disagreed. While I agree with you that basically the amp in question is essentially useless for the vast majority of users, particularly if they are using anything but horns. I disagree that low power amps do not have value. Some of the best sounding amps in my experience are low powered designs. The higher powered version of the same amp in many cases ( most cases?) are not going to sound as great as their lower powered brethren. YMMV.

9 wpc is a decent single ended tube amp output, would need to be run with very high efficiency speakers, usually horn loaded units of which there are many good ones

that sub-segment of the high end market has many proponents, most very experienced audiophiles and music lovers...music made by those systems can sound stunningly good

gordon rankin, audio note, audion, cary audio among others are very well known for making lovely amps with low outputs that have great purity

so what’s the big deal and why the belly aching?

If I really want to know what a component sounds like, I don’t read the TAS review.  They rarely bother to compare the item under review to another comparable product (too much work and accountability in that), and in many cases they don’t even list the comparable component used in the reviewer’s system if they even bother to list that system at all.  Joke. 

Agreed. Reviews used to be shootouts between competing components. Now they are just glorified write ups of products already deemed praiseworthy by the publishers and serve no useful purpose other than light entertainment. 

Interestingly enough, I read that TAS review today. I ALWAYS read the component’s specs, although I knew it was a low powered SET amp. I also looked at the list of the reviewer’s associated equipment to see what speakers were used for the review - Basszilla Platinum Edition MKII DIY (WHO?) and Fleetwood DeVille. Admittedly, I am unfamiliar with either of these but knew that with an amp putting out the LISTED 9W pc, they would have to have high sensitivity. Sorry, but anyone spending $17,000 on an amp without knowing if it would work in his own application deserves any outcome he gets.

" @millercarbon  The specs section is not really where most readers are going to look that closely, at least IMO. The information on the output is not highlighted in any way in the spec section. Like I stated, the extremely low output is not mentioned anywhere in the body of the review."

I actually go there first because they state the price among the specs.  This way I know if I'm wasting my time reading the rest of the review.

@noromance 

the purpose that those write ups serve is to reap advertising dollars, or more accurately, the write ups are the reward to advertisers

just look at the recommended components list -- there is 100% correlation to advertising LOL

Seems like the essential issue the OP is questioning is the responsibility of the reviewer. He's insisting the reviewer should educate the 'casual listener' on not just this amp, but how amplifier output and distortion generally relate to speaker sensitivity. Can't say I agree with the premise, and I'd assume the reviewer would not either.

And, I'm not sure "How many even somewhat seasoned a’philes have made the mistake of matching a flea powered amp with a less than favorable speaker load?" Seems like making a true mistake would be indication of pretty light seasoning, as this probably implies ignorance of Hifi basics, standard research prior to purchase, in home trial with knowledge of return policy, etc.

I am just wondering, what folks think of Art Dudley's ( RIP ) review of this amp in the January 2019 Stereophile Magazine. Although reviews are always " good " these days, for reasons discussed above, I miss the writing of A.D. Enjoy.....

@daj That is precisely what I am getting at. Although you seem to negate this, I believe that a reviewer has a responsibility to a reader to educate them as to what the possible issues (failings) of the product are...and not, as some of the other members here have commented on...simply to write advertising prose. Like Atmasphere commented above, this omission is actually pretty important, and leads to a failure on the reviewer’s behalf, IMO.

The amplifier has no "failings". It is exactly what it purports to be and will work well as intended. There were no "omissions". The power output was listed in the specifications. Have we gotten so mentally lazy that we need to be told that we can't play an LP in a CD player?

The amplifier may not have failings in doing what it was designed to do, within its very very limited parameters. That’s not the point here, what is the point is that the reviewer never brought up the limitations that are inherent with a design like this. I think these limitations are severe enough to disqualify this amp from most people’s ability to utilize them successfully. Since there seems to be some disbelief that folks would buy this amp without already knowing its short comings, let me relate a story that happened recently to a very sophisticated and experienced audiophile friend of mine...This gentleman goes shopping for a new amp for his fairly inefficient speakers from the same dealer that he had acquired the speakers from. The dealer sells him a low powered amp that ‘should’ work with his speakers and in his room. My friend believes that this tube amp should work, as it had a very favorable review in an audiophile magazine with good crede. Unfortunately, after about a month of trying to get the amp to work well in his system, he came to the realization that the amp in question was simply unable to properly drive his speakers, resulting in not only a ton of frustration, but ultimately a significant loss when he came to sell the amp!
Now, IMHO if the dealer or the reviewer had mentioned the fact that this amp has severe limitation in its ability to drive less than ultra efficient speakers, do we all think that my friend would have made this mistake?
BTW, I’m not saying an Air Tight dealer would lead a buyer on in this regard with reference to this particular amp, but again, the reviewer said nothing about the amps severe limitations ( ok,different from failings). An omission that I believe was significant and unfortunate.

But daveyf, now you have a grievance with the amplifier's designer too? It seems like you're arguing for hand holding for a potentially uninformed consumer. While I agree it may be nice if such education is readily provided by reviewers and HiFi mags in general, I don't feel a reviewer is being negligent if they don't caution the naive buyer on this sort of consideration. You obviously know better. Who do you imagine is the consumer who'd get suckered here? It seems to me the onus is on the buyer, especially with a high dollar niche product such as this. With so much to learn in the world of HiFi, wouldn't it be really dumb and irresponsible to throw that kind of money around without knowing what you're doing or being savvy enough to get  proper guidance (and not necessarily from a review in a mag)? I think reviewers have other objectives.

The buyer of expensive gear should be somewhat educated on the product, not relying on a review, and use due diligence. I cannot find the Absolute Sound review on line, so if anyone can paste it here, I would like to read it. Maybe I might feel some of what davey is talking about, but not likely.

@daj  Please point to where I have stated I have a grievance with the amps designer! Not the case at all. 
@mrdecibel Unfortunately, what a lot of folks rely on to get their education on an audio product is a review of said product in a well recognized audio magazine. Whether this is a smart thing to do or not is debatable, but I think most of us can agree that a lot of hobbyists give a great deal of creed to a rave review. As such, i think the omission I have been discussing is pertinent and problematical. YMMV.

I ALWAYS read the component’s specs, although I knew it was a low powered SET amp.

The specs section is not really where most readers are going to look 

Amazingly, the second post followed immediately after the first. Almost as if, who cares how obviously out of touch this looks, just as long as I can get a dig in. Pathetic.

My solid state pure class A single ended sugden @ 30 watts into 8 ohms (40 into 4 ohms) sounds better than my 90 watt class AB amp, at least to my ears. It sounds effortless and organic as well as dynamic. It’s actually an amazing amplifier whether it be playing at low volumes ( which it does very well with no lack of detail), or at higher volumes. Thus far, I see no draw back from going with less power to get a more pure (subjective) sound. My speakers are only 89/90 DB. Yes, it’s not a tube amp similar to what the OP mentioned, but still a low powered amp driving a moderately sensitive speaker well.

@millercarbon Chuck, If you don’t like my thread, I suggest you place it on ignore.

I think the OP isn’t a seasoned audiophile for a couple of reasons:
* if you see an amp that is 9 watts or something on the low watts side, you know this amp will need high efficient speakers in the 100db range. Nobody drives an amp at its maximum volume, so you really have much lower watts than 9 to play with.
* usually the specs section indicates if the watts are class A or A/AB. This in itself is very important. I have read many of this reviewers reviews and he usually states what class watts it provides. * you either match your amp to your existing speakers or you match your speakers to your amps specs. If you have 87db speakers, which aren’t that efficient, I would look at amps in the range of 200 watts or more. If I already had a 9 watt set amp, I would buy 100db efficient speakers. System synergy!
* you need to also look at specs from a reputable reviewer or manufacturer especially if you are looking for efficient speakers. For example, if you read in the latest stereophile recommended components section, they found out that the tekton speaker was rated in the middle 90’s efficiency from the manufacturer whereas the stereophile review tested them at mid-high 80’s efficiency, this is a huge difference. This usually happens in the cheaper line of products. It wouldn’t matter much if you were going to drive them with a 200 watt amp, but if I had a smaller set amp, I’d be upset.
* $15k isn’t that expensive for a quality amp, whether it’s a class A 2 watt amp or a 300 watt class a/ab amp, there is much more to an amp than its watts

I used to always read the specs section first to see price before I decide to read the review. But I am letting both subs to TAS and Stereophile expire....just got tired of reading glorified ads written by gushing reviewers for ultra-expensive equipment, that regular music lovers are not excited about. Only the reviewers seem excited about these products. The devil is in the details, which often are not in these reviews. 

Reading forums and looking at specs is why I was very hesitant to buy Vandersteen model 2’s to pair with my Schiit Aegir. I am glad I did not listen to the opinions out there as the two together sound fantastic and will get loud enough to to shake the house. You can go by specs only but at the end of the day it is your ears that matter.

Why would you consider buying an amp like this in the first place if it puts out that amount of distortion?  There are better choices.

i have to say, this thread cracks me up

the full comic, ironic genius of this forum all on display, all at once

op - with 1800 posts, being called a non-audiophile HAHAHA he should be on a sweater sewing forum then

chuck m getting his face slaps and hand claps in HAHAHA

op reads a stereophile review (the most blatantly commercial stereo magazine out there) gets mad dick olsher doesn’t say an air tight tube amp has low power in his text review (clearly stated in the specs), complains bitterly he is wronged HAHAHA

op writes paragraphs upon paragraphs, post after post, to subsequently defend his position, restate his

LIFE IS SHORT - WE SHOULD ALL SPEND LESS TIME ARGUING WITH STRANGERS WE COULD CARE LESS ABOUT ON THE INTERNET

people, let's try to learn and share info on this site, not rant...

i am going for a swim get some cardio now, have a good day all!

I agree a good review covers what is needed to get best performance from any piece of gear especially those with limitations like low power amps or inefficient speakers.

Then again quality of reviews varies widely. You would hope that the premier publications do diligence, but.....

Vendors definitely do not advertise the limitations of their gear. Why? Because it is bad for sales.

Independent sources should though.

At least the specs are there for those capable of synthesizing them properly.

Here are the last sentences from the review:

"It gives me great pleasure to crown the ATM-300R as the new king of low-power amplification. I've yet to audition a more musically convincing low-power amplifier at any price point. Simply put: an awesome display of the power of the first watt."

What more do you want?

@p05129  You are right, I am NOT a seasoned a'phile, certainly no where near as seasoned ( whoever that means?) as you!  ;0)

@aewarren  Does it not concern you at least a little bit that the reviewer in the Absolute Sound ( NOT Stereophile) omitted the fact that this amp needs to be used only with the utmost efficient speakers. No others need apply. Ralph ( atmasphere) seems to get my point about this glaring omission, surprising that so many others seemingly do not! 

Does it really need to have the words to be spoken, that " a 9 wpc tube amp, should be used with high efficiency speakers " ? Maybe to the layman. You, davey, are not a layman. Anyone reading the Absolute Sound, and having 1800 posts here, should assume it. On the other hand, if volume levels are kept low, or the listening environment is not cavernous, or the music is gentle ( not cannon shots of the 1812 ), 9 wpc can work, with an 87 db speaker. I still have not read the AS review, but considering a year and a half ago, the Stereophile review I mentioned above, was released on this amp, and AD goes into what davey is asking, the question could have been answered for him. BTW, Atmasphere, might agree with you, but as far as I am concerned, Ralph is being the gentleman he is, holding your hand. Good day, be well, and stay safe, to all.

daveyf, I said that "few low power amps could match." I did not say that no low power amp could match. There are some excellent low powered amps given the right speaker. My very first amp was a Dynakit ST 70. But for the last 40 years I have had relatively inefficient Ribbon or ES loudspeakers and frankly, low powered amps need not apply if you want the dynamic range of these speakers expressed in full. 
Diving Klipsch Cornwalls the Dynakit ST 70 would sound supreme. Like ESLs no but, very enjoyable just the same.

Folks, where do I give the impression that I am the one being misled from the article I quoted in the OP?
Absolute Sound is a magazine that is read by a wide variety of audience demographic. ( Most probably fairly experienced audiophiles, BUT NOT ALL!).  I am fairly certain that there are people who are in the market for an amp that read reviews in these periodicals and rely on what the reviewer states. By omitting this very important piece of information, I personally believe that the reviewer is not doing any service to his readership. Clearly others think this is no problem, as they think that anyone who would consider such a purchase should either be a) fully educated as to its limitations from past experience or b) willing to accept that the buyer should be beware and as such if it is a non-working solution for their amp needs --well that's just too bad. 

Interesting perspectives here from my point of view...and educational to me.

Dat dare horse done got beat to death, but p.s:

@daj  Please point to where I have stated I have a grievance with the amps designer! --
"I believe that a reviewer has a responsibility to a reader to educate them as to what the possible issues (failings) of the product are"

Implying the product's power output is it's failing. Not so.

@daj Perhaps you are trying to read too much into what I am getting at...

No daveyf, it certainly does not concern me that TAS omitted what was obvious to nearly everyone, even yourself. The reviewer also omitted the fact that you have to plug it in for it to work. Maybe if you read the review again with comprehension, you’ll understand why you are getting so much backlash. And no one had to tell me that I shouldn’t buy a VW Bug to pull my travel trailer either.

@aewarren. Your posts say a lot about you. I certainly hope that you never find yourself in a position of disadvantage because someone failed to disclose something to you..

Maybe then we can talk about comprehension...or lack thereof!

I would make a different point about the problem with the review.  I am not in the market for a low power amp or for $15,000 amp of any power.  The knowledge that this is a low power amp that costs $15,000 would very likely inform my decision about whether to read the review ... I shouldn't have to read to the end of a long review to find that out.  To make the point a little more sharply, suppose TAS were to publish a long and detailed amplifier review that ended with the sentence "Unfortunately, only 10 of these amplifiers were manufactured and they were all destroyed when the factory exploded."  Would't you feel sort of cheated that you had read an entire review of a non-existent product? 
[I guess this might be OK on April 1, but not in September.]

@billzame. Great points. In this particular review, there is actually no mention of the output power of this amp in the body of the piece. So, one could actually read the whole piece and not realize what that is!

@ billzame - hi there, I don’t mean to be contentious regarding your recent point, but I have something that might give you some room for thought - being new to the whole high end audio hifi hobby, I’ve poured over so many articles, reviews and everything audiogon has to offer, and I’ve discovered something interesting - I’ve never seen reviews as necessarily written for the sole purpose of one’s selling, or my search for, a particular product - I read everything I come across to learn more about details,; about concepts; about audible and inaudible differences; about power cords; about what certain reviewers specific preferences are for certain products I may not have listened to, in comparison to those that I have; and just about everything related to our hifi world, in order to understand the complex relationships between technology and the human ear. I may be mistaken, but I believe most audiophiles read for the sake of deeper knowledge too, and that the specific purpose of buying is not necessarily the most important. Imagine what might have been missed in the review if one merely focussed on the specifications of cost and power output that were already at the start of the review! And, even if specifications were all that were desired, I have been powering my 88db sensitive speakers with a 15wpc SET amp for the past six months to the most amazing sound - numbers that a hifi component exhibits as an isolated object doesn’t really tell any truly accurate story, because it will never be isolated in use, in being a part of a very specific set of complex relationships within any given system. I have found that the focus on specification numbers as an object of research is an unhealthy habit, as it might make me miss everything else more important about the profound and critical relationships that musical reproduction and listening is truly about. 
In friendship : ) - kevin

@kevn  Kevin, perhaps you could answer my question. If you read the review I alluded to in my OP, there is no mention in the body of the work that the amp in question puts out a maximum of 9watts/ch and at 10% distortion. Furthermore, there is no mention of what kind of speakers would seem to be mandatory if one is to consider this amp. Given that you state that the relationship between components is a very complex aspect ( which I concur with), I ask this:  if you had bought this amp and hooked it up to your 88db sensitive speakers, and the result was far from what you are expecting based on the review, what would your thoughts be?

Hey daveyf, thanks for your question - well, first off, I read to the very end of every review for information I might have missed, or that could tell me everything I might need to know about the equipment in question. And I would find the specifications or measurements at some point, which in this particular case, was in the specs section. And this alone would never have been sufficient for me, obviously. For an item of any cost, let alone this particularly higher priced piece, I would have proceeded to then uncover, through more reviews, friends, specialists and the like, every thing I could possibly find on it, in order to develop a good picture for myself regarding what I’d be actually buying. You see, any review is just written by another human being, more experienced or otherwise, but nonetheless as human and as imperfect as you and I are. And that’s all that any review is, another small piece of the huge jigsaw that a component is about, you see? To merely take any one single review as gospel, would be to dis-service to yourself, and place unfair judgement on another human being, who, even as a professional reviewer, might possibly not know even as much as you or me, regarding certain aspects of our audio world. But I will still read every single word written in critical appraisal, for everything else he or she might know more about, and the smallest clues that might help better my understanding of what the product does, or can do. Everyone told me my 15wpc SET would never work with my middling/low sensitivity speakers, but I had a hunch the solid state rectifiers would control the bass well enough, and indeed they did. There are simply too many ways to skin a cat, to shut anything down purely on account of specifications and measurements, and this is the reason why a single review, whether biased for or against the numbers, will never do : ) - I hope this all makes sense! 
In friendship - kevin