Whay SET amps and horns work

[Colin]

Why The SET

And

Efficient Loudspeaker Approach Works

by Steve Deckert

To reach the same loudness level as the 96dB loudspeaker will with 1 watt requires over 8 watts on the 86dB loudspeaker. If we used 2 watts on the 96dB loudspeaker the other would require 16 watts to keep up. If we used 4 watts on the 96dB loudspeaker the other would require 32 watts to keep up.

Experience has taught me that by far the easiest way to get a liquid sound that becomes holographic with stunning clarity and detail, something that excites the listener, is to set him up with an SET and simple pair of efficient loudspeakers. It also usually ends up being the least expensive solution.

http://www.enjoythemusic.com/magazine/manufacture/0703/

[NOSValves]

Yea its pretty interesting that my Mark III's playing at 1 Watt for majority of a given song often produce 10 watts and above peaks to keep up with the transients ! With a 2A3 SET Paramours I rarely witnessed peaks above 2 watts if you like your music very relaxed I would say SET is definitely the way to go ! Its all subjective like everything else in this hobby. Me I want my music to be reproduced honestly like the artist intended the recording to do not with some magical mystique that I will never hear at a live event ! Audioflynn and I went to see Neil Young and Crazy Horse the weekend before last (Thanks to Audioflynn for the tickets) I was amazed at how similar the entire concert sounded to my system only my system can produce a higher SLP !! The concert was at the DTE music center (Pine Knob) that I believe is acoustically pretty darn good and we had excellent seats ! Oh and Neil Young was awesome !!

Craig

[Pack Rat]

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On 7/1/2003 5:24:19 PM NOSValves wrote:

Yea its pretty interesting that my Mark III's playing at 1 Watt for majority of a given song often produce 10 watts and above peaks to keep up with the transients ! With a 2A3 SET Paramours I rarely witnessed peaks above 2 watts if you like your music very relaxed I would say SET is definitely the way to go ! Its all subjective like everything else in this hobby. Me I want my music to be reproduced honestly like the artist attended the recording to do not with some magical mystique that I will never hear at a live event !

Craig

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It's all a matter of perspective. Though the Mark IIIs may be outputting 1 watt with peaks reaching 10 watts for your normal listening the 2A3s are probably pushing .2 watts with 2 watt peaks. The headroom is the same and the more efficeint speakers required by the 2A3s compensates for the low output.

Musical reproduction will always be subjective and everyone has an opinion as to which method sounds the best.

I personally love the sound of my SETs, actually most SETs, but when it comes down to filling a room with sound I fire up the Maggies with 250 watts/channel of clean solid state and a 500 watt sub. Everyone that's listened likes the sound of the SETs and is usually impressed with the soundstage, ambience and the "I can see the band" clarity but when the same track is played on the Maggies with light dimming power the response is "WOW".

Like I said at the start, perspective.

[Triode Pete]

Some more info from the Steve Deckert Article;

........."To answer this, lets start with the advantages of a SET amplifier over

any other type. A Single Ended Triode is the simplest circuit design

there is, using the least number of parts. Typically this is a driver stage

coupled to a single output device. Triodes do not require negative

feedback, something found in most all push-pull circuits, solid state or

tube. Negative feedback is used to lower distortion specs and in the

case of solid state devices it is often the only thing keeping the

transistors from exploding all over the inside of your amplifier. Feedback

a problem? If you dont mind the time smear it creates and the resulting

2 dimensional sound stage, then no I guess its probably not.

Aside from the amplifiers superiority by simplicity, there is a more

profound reason for using SET amplifiers. The magic predominately lies

in the first watt. By magic I mean inner detail and most of the

dynamics. For example, a pair of 96dB loudspeakers playing with one

watt of power against the average noise floor in your listening room

(55dB) is 40dB of dynamic range. (96 55 = 41dB) Adding a second

watt increases the dynamic range by only 3 dB. For every additional 3dB

you need to double your power. This should clearly illustrate that there

is over 10 times the dynamic range in the first watt as there is in the

second."

The K.I.S.S. principle rules with horns. High efficiency horns are so damn transparent that the simplest flaws (including negative feedback) in the system will be revealed. The dynamics is a crock, too. In a home environment (not an auditorium) with 104 dB horns, a few watts is all you'll ever need (unless you're a Twisted Sister headbanger... & that's fine too, just get a Monster Amp to use with your hearing aid).

"What the world needs is a good 5 watt amplifier"...... Paul W. Klipsch

Have fun & enjoy,

Pete

[Deang]

"It's all a matter of perspective. Though the Mark IIIs may be outputting 1 watt with peaks reaching 10 watts for your normal listening the 2A3s are probably pushing .2 watts with 2 watt peaks."

It doesn't work that way. Craig used both amps on the same set of speakers - his LaScalas. What he is saying is that with the LaScalas -- The Dynacos were generating 10 watt peaks at 1 watt continuous, and the Parmours were generating 2 watt peaks at 1 watt continuous.

.........."To answer this, lets start with the advantages of a SET amplifier over

any other type. A Single Ended Triode is the simplest circuit design

there is, using the least number of parts. Typically this is a driver stage

coupled to a single output device."

To say that less parts and simplicity in the extreme is over-simplistic. I outright reject the idea that advancements in circuit design over 30 years was nothing more than back-peddling.

........."Triodes do not require negative feedback, something found in most all push-pull circuits, solid state or

tube. Negative feedback is used to lower distortion specs..."

Actually, negative feedback is used to lower distortion levels, not just distortion 'specs'. People make this sound like a bad thing, which I find bizarre. There is nothing anywhere, from an engineering standpoint -- that says negative feedback is bad. In fact, a small amount of feedback is a good thing. The problem is too much -- not none at all. Low feedback designs sound great.

.........."Feedback a problem? If you dont mind the time smear it creates and the resulting

2 dimensional sound stage..."

Time smear within the ciruit, or at the ears? Who came up with this one? Are we talking about that itty bitty feedback loop causing a "timing miscue" within the circuit -- and then through the speakers? This is nutty. Should we get into the timing issues related to reflections in a room to put this in perspective? As far as the dimensionality issue goes, my experience doesn't line up with that comment. I think SET has more midrange clarity, but at a cost. Anyone is welcome anytime to come hear my 2-dimensional Quicksilvers.

.........."The magic predominately lies in the first watt."

What magic? The first watt is the first watt no matter what amp you're using. He's wrong -- the "magic" is in the last watt.

.........."By magic I mean inner detail and most of the dynamics."

Again, he's wrong. Superior dynamics come from being able to complete the waveforms at most SPLs. This is found in the last watt.

.........."For example, a pair of 96dB loudspeakers playing with one

watt of power against the average noise floor in your listening room

(55dB) is 40dB of dynamic range. (96 55 = 41dB) Adding a second

watt increases the dynamic range by only 3 dB. For every additional 3dB

you need to double your power. This should clearly illustrate that there

is over 10 times the dynamic range in the first watt as there is in the

second."

I love this one. Yeah, this is how it is -- so what? It doesn't go the extra mile. Yes, the midrange is where we live, but without sufficient headroom to stay out of distortion (regardless whether it's even or odd order) - we die.

"...The dynamics is a crock, too. In a home environment (not an auditorium) with 104 dB horns, a few watts is all you'll ever need (unless you're a Twisted Sister headbanger... & that's fine too, just get a Monster Amp to use with your hearing aid)."

Your confusing "dynamics" with SPL. They are related but not the same. I could easily hit 95db with the Apollos, and though sounding very good, could sound a little pinched and strained at times. 95db with my Quicksilvers and Leo's little resistor tweak (takes me down to 30wpc) is complete audio nirvana. I entertain thoughts of selling off and trying something different -- but then I sit and listen and realize what a completely retarded idea it is. 95db is where I like to listen -- hardly dangerous for my somewhat short listening sessions (a CD) because of all the things going on in life. At any rate -- 95 db with the Ultra-linear, 12db of negative feedback, SS rectified, parallel push-pull Quicksilvers -- completely buries the Class A, no feedback, 18wpc, DHT Apollos playing at the same level. It's simply a much smoother, tighter, more effortless sound. No pinch, no strain -- what can I say?

Incidentlly, regarding the simplicity thing. It is possible to use a minimalist design with push-pulls. My Quicksilvers have a total of 5 parts directly in the signal path.

"What the world needs is a good 5 watt amplifier"...... Paul W. Klipsch

PK said this very early on when good power was relatively expensive. In a Dope from Hope article many years later, PK said 20 watts was optimal for the K-horns.

My signature is tongue in cheek. I'm very happy with 30-40 watts on my RF-7's. If I had K-horns -- I could easily be happy with 20 watts. I would most certainly enjoy something like Tony is using right -- some nice 2A3 push-pulls.

Something else we could turn the conversation to is the concept of recovery after clipping.

[NOSValves]

"What the world needs is a good 5 watt amplifier"...... Paul W. Klipsch

I love that line !!! Paul Klipsch said that when standard fair was your 2 and 3 watt amps !! If you read dope from hope as things progressed Paul Klipsch himself was recommending more and more CLEAN wattage for even Klipsch horns !

The music I was doing this testing with was "Dire Straights" hardly head banger twisted sister type stuff very main stream.

Craig

PS Pete I would love to have you come over and point out the Negative feedback in my system !! Negative feedback in a push pull amp is a positive when tuned properly not a negative.

[NOSValves]

Also Steve Deckert should also say from a business standpoint the following

simple circuit - low production cost - high price - enormous profits

Although I'm sure he is a very sharp guy I would hardly say his opinion is neutral or myself for that matter !

[Deang]

Yipppe ei ai kiaaa kiaaa -- Quasi-Comp Darlington amps rule!

I just bought an old, mint Adcom 555 II for $375 that I'm going bridge for a killer sub I want to build.

[Daddy Dee]

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On 7/2/2003 8:11:15 AM DeanG wrote:

"It's all a matter of perspective. Though the Mark IIIs may be outputting 1 watt with peaks reaching 10 watts for your normal listening the 2A3s are probably pushing .2 watts with 2 watt peaks."

It doesn't work that way. Craig used both amps on the same set of speakers - his LaScalas. What he is saying is that with the LaScalas -- The Dynacos were generating 10 watt peaks at 1 watt continuous, and the Parmours were generating 2 watt peaks at 1 watt continuous.

Something else we could turn the conversation to is the concept of recovery after clipping.

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

O.K. guys, I've got a couple of questions, and of course there is some subjective preference here, too.

For the engineering types, did the guy may any legitimate points on his review on the original link in this thread?

Dean, I'd sure be interested to hear about recovery after clipping. Is this the deal in my 2A3's seem to be more forgiving than one would expect with their small power?

I've noticed that most 2A3's are rated at 3.5 wpc. Does anyone know why the Paraglow's are rated at 2.7 (I think) wpc?

When PWK is saying "What the world needs is a good 5 watt amp." does this mean he didn't care for a 300b SET?

Also, with a 2A3 in PP, is this multiple 2a3's in series or parallel or whatever push pull, in order to have more powerful output.... anyway the question is, do the 2A3 lovers think this still does the magic for them? Or does it have to be low power.

Appreciate any feedback here. Didn't want to start a new thread on this one.

Best REgards,

Dee

[Deang]

Yeah, I'm a little worried. Only 600 watts bridged in mono. I hope it's enough.

I call it my BASH amp.

Takes a little bit of work, always does -- but they clean up really nice. Found a patch of cat hair under the transformer -- I don't even want to know how it got there.

[Triode Pete]

The focus of the posting is "Why The SET And Efficient Loudspeaker Approach Works" . Pretty simple, eh?

The conclusion is that IT DOES WORK! It may be not your cup of tea or personal preference.

My system has evolved around the heart of it, the K-horns. Have tried numerous amps; McIntosh SS ( a bit harsh), single-ended 300B (nice but light bass), Fisher 500C (7591A p-p -- nice but missing some inner details), push-pull parallel 2A3 (slam & authority but missing finesse) and finally my favorite, 2A3 SET (it provides most enjoyment to me).

Not all amps or topologies (or tubes) are the same. All will sound different, not necessarily better. I doubt that those Apollo's have that true SET magic or Ron W would still be making them! It's incredibly subjective! My brother-in-law has Cornwalls with a pair of p-p-p 2A3's. He tried SET but preferred push-pull. With Cornwalls, there's a big difference between 14 watts & 3.5 watts.

You want to start any interesting thread --- PREAMPS!

BTW - I have kept my tube gear over the years & sold all the solid state gear (except for the garage system). If I had inefficent speakers (like Magnepans), I'd probably have all solid state gear. Can't use SET for inefficient speakers!

To each, his own (set of ears),

Pete

PS - Craig, I'd love to hear your negative feedback system!

[Parrot]

Excellent point, Mark: "And those so-called merits are not merits at all, they are simply "aspects". Low power is not a merit, it is an aspect of the design. No feedback is not a merit, it is an aspect."

[Parrot]

Craig said: "simple circuit - low production cost - high price - enormous profits"

LOL!!! Yeah, since these amps have almost nothing in them, why aren't they $100 instead of several thousand?

[Painful Reality]

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On 7/2/2003 8:14:17 PM mdeneen wrote:

He he -- if I was looking for enormous profits - - I'd look into the HiFi wire bid'niz.

mdeneen

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You bet... especially after realizing that the "made especially for us" ultra pure copper wire was actually stripped down Canare GS-6.

[NOSValves]

Canare GS-6 is some great interconnect wire for 45 cents a foot !!

[Deang]

45 cents a foot!! What a rip off. I can't believe you'd pay that much for wire!!

[mike stehr]

Hell, you mentioned to get some 10 awg for my subwoofers.

I bought some 10 gauge solid core stranded stuff, about 24, 22 awg per strand. Ten or twelve strands or so.

Some cheap sh*t for home wiring from home despot, around 14 cents a foot.

It works, I seem to notice the bass tighten up.

I need to buy some more CAT5, twist up some sub cables.

[Deang]

What you have on there now is fine for bass.

Just thinking about twisting CAT5 makes my hands swell up.

[Triode Pete]

mdeneen -- I've heard a lot of reconditioned 1930's gear (not necessarily SET) that will blow the doors off modern 21st century gear. By "blow", I mean "better".

Questionable Science??? --- What is the most linear amplifying device ever made??? The TRIODE (yeah, late 1920's 1930's technology). On a pair of Klipschorns, show & prove (give me an example) to me how a typical 14 gain stage solid state amplifier (with plenty of negative feedback to keep it linear) sounds has superior sonics to a simple 2 gain stage SET( that's naturally distortion free). Hook-up a Phase Linear amp to K-horns & see how fast you'll run from the room. You'll understand why Klipsch got a bad reputation for those awful, colored, honky horns that no audiophool would ever own!

Simple doesn't mean cheap! A good SET will have high quality wound transformers (power supply, choke & output) as well as a good lay-out & design with good tubes (I prefer USA made low-powered varieties). Forget about the fancy schmancy caps, resistors & wires for now. These parts can be very expensive which can contribute to a high $ / watt cost but an acceptable $/ lb cost. This holds true for push-pull tube designs also which I like.

C'mon, you really think a complicated design will sound better?? Nonsense. Just imagine if the K-horn didn't require a crossover...how spooky transparent it would be? Ever hear a speaker without a crossover?? They sound surreal & fantastic (usually in the midrange) but are not my cup of java due to bandwidth limitations (since most are single driver).

ASSININE - that would be the JC Whitney syndrome of complicated designs which actually degrades the audio signal. You should try to get all the accessories available for your car from the JC Whitney catalog! That way, you'll get 1000 mpg while travelling at 200 mph with your car. This applies to your hot rod audio system too!

My belief is to keep it as simple as possible (this doesn't mean necessarily cheaper) for a superior sounding system!

Peace,

Pete

[leok]

mdeneen,

I agree with Triode Pete, except I would provide an additional restriction and that is, the amp has to work well at the low levels I enjoy through my RF-7s and Forte-IIs. I do find that power of the 2A3 SET is a limitation, and actually switch to the pp or Tripath amps when I want a little more punch.

What I'm looking for is bery high quality sound within which I can hear details of acoustic instrument timbres and hall ambiance. I don't care too much how I get it, but have found, so far, that only the Tripath, triode/no-feedback/pp, and SET do the job. None of them are perfect, but all of them are enjoyable.

If you know something that can do a better job, I'm interested. By the way, you are the person who encouraged me to try the differential phase splitter I'm now using in the pp design, so I do listen to and respect your ideas. I think it would be terrific if there was a realistic ss contender that competed well in the low power detail region dominated by SET designs. So far, the best I've heard is the P6D.

leok