The SET Debate (again)

[sfogg]

Rick,

"I don't think the higher power ratings and upper power warnings came before the SS era when tweeters started frying. Too low power from an SS amp's clipping would put excess power to the tweeter just as well as too high an amplifier power. With tubes more benign clipping characteristics, blown tweeters and excessive warrantee claims were not a problem."

I don't think that was even the problem with frying tweeters. I think it was that some of those SS amps had bad turn on/off transients.. those are what was killing tweeters as I recall according to one of the Dope From Hope's.

Shawn

[edwinr]

I have have only a limited technical background. My opinions have been formed by extensive listening. I do own Klipschorns. They were made in 1986 and feature an oiled walnut veneer. They have the AK2 crossovers.

In referring to the mighty Klipschorn, I believe we may very well achieve 100db plus spl's with low powered amplifiers. I concede that some Klipsch literature appears to indicate this is a possibility. We must also remember that some of this literature may have been written by marketing people, and as such, aimed at those that already have amplifiers that are not very powerful. In promoting the Klipschorn/La Scala, we would not want to exclude this market.

It is clear from my listening experiences, low powered amplifers CAN achieve reasonably loud listening levels. BUT, they cannot do so while maintaining, without compression, the micro and macro dynamics that are such an important feature of accurate music reproduction. While a low powered SET can sound very nice on Klipschorns with certain music and at lower listening levels, such a combination is not conducive to accurate music reproduction.

I believe, that to do a low powered SET justice, we would need to match such an amplifier with an as friendly load as possible. That is, a more resistive load rather than a reactive load. From my limited technical understanding, some loudspeakers present such a reactive load. From my listening, I would suggest that the Klipschorn may fall into this category. Those speakers that may be more SET friendly, include those designs that feature no crossover - either a Lowther based design or a Stamm driver derivitive. I suggest these simple designs may be more resistive loads.

There are those on this Forum (I mean this sincerely) that are blessed with the ability to detect the differences between one cable and another. I cannot. Therefore I have not factored in cables and interconnects into my listening impression. Frankly, I cannot see how changing a piece of wire could possibly influence what I have heard.

[3dzapper]

Remember too, until the SS age and some better belt driven and then DD turntables, even broadcast stations used rumbly pinch wheel TTs and heavy cumbersome tone arms. These factors contributed to the lower bass and treble content of recorded music. This reduced bass content lowered the power required from the amplifier.

With today's recordings, SET shows it's Achilles Heel more readily. That is, the bass is easily driving the amp to it's limits. On accustic jazz the limits are further out but still there in the form of loose, flubby bass at higher volumes. The trade off is that with their simple design and lack of feedback, the mids and treble are clearer.

Rick

[greg928gts]

Even though I have a dozen amplifiers around here that I can plug into my system, when I do, they don't stay there for long.

I sense the limitation of my SET amps, yet I don't enjoy anything else I have quite as much.

The last person who sat on my couch and listened to my system left shaking his head in disbelief that he was listening to 2 watts per channel of power. That was Eric Fritzeen, the guy who bought my last set of Cornwalls. It was more than the volume attained with the low power, it was the overall presentation of pure music.

I have no doubt that he would have been equally impressed with a nice PP tube amp that night. He had heard the negative talk about SET and his expectations were not very high. He left here with a newfound respect for the SET topography.

Anyway, even with all the experimenting I do to improve my system, it's always the SET power that I come back to. That's enough for me for now.

Greg

[D-MAN]

Grain of salt time...

Let me preface this by stating for the record:

"I DO NOT NOW NOR HAVE I EVER OWNED AN 'SET' AMP"

That being said, the ONLY axe I have to grind here is concerning the minimum wattage required to produce a relatively flat frequency response from a Khorn. I say relatively flat because they will never actually be flat regardless of power input. But that's besides the point...

The main thing that I want to clear up is the idea that Khorns are not appropriate for use with low-powered "flea" amps, which is certainly just not the case.

I am going to make a couple of logical assumptions (at least in my mind) as part of my diatribe. One is that

one would not be concerned with this UNLESS they already had a flea powered amp and they listened to music particularily appropriate to that. The second assumption (for the sake of this argument) is that the SET in question is a flea-powered or otherwise low-powered amp of let's say 8 watts like a nice 300B would be.

First of all the crossover network and all-horn-loaded drivers used in the Khorn provide a relatively stable reactance (or impedance) seen by the amp, especially compared with other drivers, even the famous single cone full-range drivers especially in vogue for flea amps. This is because the horn-loading uses the natural resistance imposed by horn loading on the driver to restrict excursion to a degree. Less excursion = less distortion.

Horn loading also increases efficiency in that a little diapragm at the throat is translated in moving a larger area of air at the mouth albiet to a lesser vibrational movement, but a larger area of air is moving, none-the-less.

Both of these elements result in a "less reactive" or an impedance with less variation as seen by the amplifier output stage. In particular, tube output stages benefit in that they typically use an impedance matching transformer at the output which is a little sensitive to changes in impedance. This is lessened by the use of horns, of course, and therefore provides a more stable load to the amplifier. Thus the idea that "tubes love horns".

The other thing that I'd like to point out is that those who would be interested and/or own flea-powered amps are ALREADY into the music styles that lend themselves to the level of performance achievable by high-efficiency speakers and low powered amps. Soundstaging, nuance, and detail is WHAT these folks are after in the first place.

They have geared their choice in gear to attain that. Large watts need not apply, as a matter of fact, watts will only "get in the way". It is also to be considered that at that desired level of detail, that the topology and nature of the amplifier, including its tubes has a discernable effect on the resulting output. This of course includes the use of feedback (or not) and the like.

These points are your basic inarguable things that we all like to yammer about.

So the ends justify the means, and visa-versa.

Personally, I use a high-current SS amplifier with a transformer output (also called an auto-former for its impedance matching capabilities), so it doesn't matter to me about tubes, SET, SS or whatever. But if I was going to look at SET or flea-amps, I would look at the 2.5 watt 2A3 or a 300B, in a New York minute.

What I am concerned about is the concept of horn speakers, including the Klipschorn, which is a fine example of the genre, and is STILL right up there in performance with basically all of the currently available horn-type loudspeakers. Yes, it has its inherent "problems" but being inefficient isn't one of them. And just why would anyone interested and further, NEEDING a high-efficiency speaker pass up a pair of Khorns? 104db sensitivity is RIGHT UP THERE and has been since 1946 when all the amplifiers were "flea-amps".

DM

[oldtimer]

Laughing out loud Dman, but to answer your question: No, it does not make you look fat.

[oldtimer]

Ah yes 3D, acoustic jazz. I love the sound of my Forte II's with this sound. They shine with Stanley Clarke's solo on Chick Corea's Return to Forever (Sometime ago/La fiesta). Plus I love the old 50's and 60's recordings using Telefunken mikes with Dizzy Gillespie, Charlie Parker, Miles Davis, and guys like John Coltrane. Natural horn sounds really sound great on horns! (naturally). Be right back, got some listening to do.....

[NOSValves]

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On 4/29/2005 8:25:07 AM silversport wrote:

ah, but I prefer a person who gives his REAL opinion on something...it lets you know where they stand...isn't THAT an uncommon concept....Stand for something! I am so tired of people saying something in order to appear invisible and not rock the boat (it apparently isn't a problem for those here however...

)

As I have found edwinr an honorable gent, I say carry on sir and thanks for your opinion...I like SS but am not against tubes so...

Bill

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Where have you been all my Klipsch Forum life

[NOSValves]

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On 4/29/2005 1:53:30 PM ben. wrote:

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Ben,

Classic

[SilverSport]

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Where have you been all my Klipsch Forum life

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Why, right here tickin' off some, ignored by others and askin' questions since December of last year...too late to the party???

Bill

[Audio Flynn]

It is clear from my listening experiences, low powered amplifers CAN achieve reasonably loud listening levels. BUT, they cannot do so while maintaining, without compression, the micro and macro dynamics that are such an important feature of accurate music reproduction. While a low powered SET can sound very nice on Klipschorns with certain music and at lower listening levels, such a combination is not conducive to accurate music reproduction.

++++++++++++++++

Very nicely written edwin!

Saved me allot of time and agony.

I heard one 300B set amp I liked that was custom made by a tube techie of 30 years; but it had limitations in dynamics.

[NOSValves]

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On 4/29/2005 7:52:56 PM greg928s4 wrote:

Even though I have a dozen amplifiers around here that I can plug into my system, when I do, they don't stay there for long.

I sense the limitation of my SET amps, yet I don't enjoy anything else I have quite as much.

The last person who sat on my couch and listened to my system left shaking his head in disbelief that he was listening to 2 watts per channel of power. That was Eric Fritzeen, the guy who bought my last set of Cornwalls. It was more than the volume attained with the low power, it was the overall presentation of pure music.

I have no doubt that he would have been equally impressed with a nice PP tube amp that night. He had heard the negative talk about SET and his expectations were not very high. He left here with a newfound respect for the SET topography.

Anyway, even with all the experimenting I do to improve my system, it's always the SET power that I come back to. That's enough for me for now.

Greg

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Greg,

I hate to even venture into this with a serious question but please give some details like

How large is your room that these K-Horns reside in ?

What music types did you audition with Eric ?

I think to get a clear picture you need to give all the details. I also think you need to invest something near what you have invested in your SET amps into PP before you can make a real judgement. I'm not sure what all PP you have tried so these details would be helpfull also.

Craig

[Audio Flynn]

How large is your room that these K-Horns reside in ?

-coat closet

What music types did you audition with Eric ?

-Concerto for flute and oboe

=============

My 2 beer 2 cents worth stupid joke.

I gotta get a life...

[kev313]

Why should Greg post the details. His post was exactly as "informational" as the original post.

He's got an opinion and he's here, celebrating the "Klipsch Forum Life," such as it is.

What amazes me about this place is how many (but thankfully not all!) from the two camps won't say PP does "A" well or poorly whereas SET does "B" well or poorly. Failing to recognize the various strengths and weaknesses of each topology makes whatever else you say a bit less credible.

Why even waste time trying to convince people what is best? How can that possibly be satisfying? Read a book. Hug your wife. Play with your kids. Go outside. LISTEN TO MUSIC.

[NOSValves]

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On 4/29/2005 10:44:25 PM kev313 wrote:

Why should Greg post the details. His post was exactly as "informational" as the original post.

He's got an opinion and he's here, celebrating the "Klipsch Forum Life," such as it is.

What amazes me about this place is how many (but thankfully not all!) from the two camps won't say PP does "A" well or poorly whereas SET does "B" well or poorly. Failing to recognize the various strengths and weaknesses of each topology makes whatever else you say a bit less credible.

Why even waste time trying to convince people what is best? How can that possibly be satisfying? Read a book. Hug your wife. Play with your kids. Go outside. LISTEN TO MUSIC.

----------------

Excuse me I didn't say a negative or positive thing about one or the other. I happen to own both! Besides that my question was clearly pointed to Greg wasn't it? I'm sure he won't mind answering my question.

Craig

[kev313]

Sorry for not being clear. The first two sentences were directed to you, Craig. The remainder of the post was directed to the...uhhh...zealots. I don't want to waste too much time on this (admitedly pointless) exercise in trying to bring a dash of rational discussion to the Heritage Club, but I did actually read your post, and know that you didn't say anything negative.

[dodger]

Granted I cannot cut and paste, however I did quote what the conflicting power needs the brochure states for the K-Horn.

That is in addition to what Bob could cut and paste.

There is the point of no power recommendation, the efficiency and one other thing - specifications available upon request.

The DFH is one good thing, but it was not the marketing tool with power statements available to the public. The selling tool.

It has been a number of years since the statement regarding a good five watt amplifier was made. There have been some improvements.

[Audible Nectar]

The Pros and Cons of SET (and no....not by Roger Waters):

When I toured the country listening to the different tube amps, SET was most certainly on the list of topologies to be considered.....and they do have some advantages, which are accentuated by high efficiency speakers.

The SET amps I listened to (Welbourne Moondogs and JFL Horus, for example) offered the most natural presentation of instruments. Cellos sound like cellos, horns like horns, human voices like human voices. Within the power output/volume limitation, I really do think they are the best topology on horns.....if you can work within the power restriction.

But that's where I ran into problems. On rock/amplified music material, SET's still sounded good at moderate volume....in fact, EXCELLENT at moderate volume......but as soon as you crank it up, the system and sound becomes like your teenage daughter and her boyfriend - they start running together.

This was the reason I didn't buy SET. Had there been an SET amp at 10-20 watts per channel that didn't break the bank, I probably would have bought one. I often ask myself what would I buy if I didn't go with the MC30's.....and I suspect that 300B would be the answer, to the best I am able to answer at this time.

I also find that I prefer tube rectified amplifiers in most cases. I'm a bit like Dean in that regard, and I think that's another reason I landed on the 30's....and why those particular amps "got in" when the other push-pulls didn't. I heard many push pull amps, and while all sounded quite good, the tube rectified MC30 offered some of that SET realism with testicles to drive the rock and roll.

I do think that SET is an excellent choice for many Klipsch owners. The only time I try to steer someone away from SET is if they want the volume. Power output IS the restriction for those considering this topology. For someone wanting to get 88-90db or less in a 16 x 20 foot room on Klipschorns, SET should do just fine.....in fact, it is recommended, even by this MC30 owner. If 30 watt SET amps didn't cost 5 figures, I suspect many more here would have SET's.

[edwinr]

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On 4/29/2005 8:05:58 PM D-MAN wrote:

Grain of salt time...

Let me preface this by stating for the record:

"I DO NOT NOW NOR HAVE I EVER OWNED AN 'SET' AMP"

That being said, the ONLY axe I have to grind here is concerning the minimum wattage required to produce a relatively flat frequency response from a Khorn. I say relatively flat because they will never actually be flat regardless of power input. But that's besides the point...

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Hi, D-MAN. Great post as usual. Lets just say that I concede that our 8 watts per channel SET amplifier and our generic 100 watts s/s amplifer both produce the same relatively flat frequency response. For our hypothetical listening test, let us also select a nontaxing listening level for the SET amplifier and run the s/s at that same arbitary level using the same source and the same high sensitivity horn speakers. My argument is, that the lower powered amplifier will still be unable to accurately reproduce the transient information that is inherent in all well recorded music. Particulary music that features non-electronic instrumentation. The human voice, using state of the art equipment, is also notoriously difficult to record accurately without some form of compression. Even with the 104db sensitivity stated for the Klipschorn, I suggest a minimum recommended power for an amplifier match should be in the 25 to 30 watt range.

Edit: Also, D-MAN, your comment: " Soundstaging, nuance, and detail is WHAT these folks are after in the first place...". I agree with your comments. BUT, how do these flea powered amps achieve this?

Answer?

By compressing this information into an easily assimilated package. We don't have to listen for it. It's all there, in our face.

[coda]

Edwin what speakers were used for the Audio Note audition?

other opinions of the SET horse differ of course,

palpable presence of the musicians

exquisite low-level detail

perfect timing of the attack and decay of each note

above all, the truth of timbre and the sheer beauty of the music

when it comes to preference, it's usually a matter of priorities (believe I heard that mentioned already, too). At this point, it's not enough to have a good mind. The main thing is to use it well.

So, why debate this again?