So Much sound from so Little power!!!

[maxg]

Shelltie,

"Max, you are stepping into damping factor and instantaneous peak power ratings, something that you don't want to involve most SET amps in discussing. One item we are missing in this small brushfire is that we are not discussing SET amps in general, but an extremely well designed and built set of monoblocs with custom features, not something you cruise over to your local stereo store and buy off the shelf."

This is a problem for SET amps even below their limits of output? I didnt know.

"If you have a 6,000 cu. ft. room that runs 25 ft wide x 20 ft.deep x 12 ft. ceiling, if you run the Moondogs at one watt accoustical power(a gift, but make it easy,) you will see 104 dB at 1 meter(3 ft.) Let us put your listening position at 15 feet and run the math. The SPL reduction factor will be the term (3/15) squared, x 2, or 8% of the SPL level at 3 ft. You will be subject to an SPL field of around 98 dB, bare and unreflected, in a perfect world. If you factor in normal losses, ie an imperfect seal (with Khorns,) electrical to accoustical energy losses, etal, and SPL levels drop accordingly."

So I wouldnt like it then? Or, to put it another way - it wouldnt do the job I did on Sunday at peak values of 92 dB at my listening position.

I know we are treading dangerous waters but these are genuine questions - as I have said repeatedly I have no experience of low ouput SET amps.

[sheltie dave]

Max, you are looking at at least 60% of an amp's output going to power the woofer. The more signal load you have in the range the woofer covers, the less you have present for mid and highs. This usually isn't a problem for Klipsch speakers, BUT they do not have benign impedance loads. Dean was driving at this characteristic, because the ALKs and AK4s are reputed to engineer this problem away due to their build design.

An amp with low power, little headroom, and a low damping factor will end up "chasing its tail", rather than driving the speaker, in conditions that Klipsch speakers may present. Cutthroat's Moondogs may be able to avoid most of these pratfalls, but again, they are Moondogs, which most often have superior iron, design, and implementation. Engineers like to design away from these problems by overengineering, often by a factor of 2 or greater. The lesser the quality, the more often problems will crop up.

You are the type of listener that would eventually biamp your horn speakers, with a dedicated amp for the woofers, and the SET monoblocks for your mids and highs. If we throw the 60% to 70% thumbrule into play with a 2 watt SET amp, that means you would want a max of a 7 watt amp for the woofers, heck, make it 10 watts. This runs you smack into the SET paradigm on volume - if you like or want endless amounts of volume in the well - then SET may not be your cup'a'tea. From the PP contingent, the argument is that SET amplification skirts or crosses the design "safety" margins for sound reproduction in too many areas to fully accomplish what is needed.

The whole scene is amusing. My Dynaco ST70 runs out of steam when I drive it hard, as I can hear the channel with the bass information getting "soft" at times as it runs out of juice. The other channel follows suit, chasing the tail. Given enough room, just about all our tube amps will show their limits. It is a question of how we set our listening paradigms, and the compromises we are will to accept. My most important listening feature is having the tubes covered, so Liam can't hurt himself Everything else is gravy...

[Cut-Throat]

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

I know we are treading dangerous waters but these are genuine questions - as I have said repeatedly I have no experience of low ouput SET amps.

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

Don't feel alone. Most of the people you are conversing with have no experience with SET amps either!

[jazman]

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On 5/24/2004 9:09:11 AM sheltie dave wrote:

Max, you are looking at at least 60% of an amp's output going to power the woofer. The more signal load you have in the range the woofer covers, the less you have present for mid and highs. This usually isn't a problem for Klipsch speakers, BUT they do not have benign impedance loads. Dean was driving at this characteristic, because the ALKs and AK4s are reputed to engineer this problem away due to their build design.

An amp with low power, little headroom, and a low damping factor will end up "chasing its tail", rather than driving the speaker, in conditions that Klipsch speakers may present. Cutthroat's Moondogs may be able to avoid most of these pratfalls, but again, they are Moondogs, which most often have superior iron, design, and implementation. Engineers like to design away from these problems by overengineering, often by a factor of 2 or greater. The lesser the quality, the more often problems will crop up.

You are the type of listener that would eventually biamp your horn speakers, with a dedicated amp for the woofers, and the SET monoblocks for your mids and highs. If we throw the 60% to 70% thumbrule into play with a 2 watt SET amp, that means you would want a max of a 7 watt amp for the woofers, heck, make it 10 watts. This runs you smack into the SET paradigm on volume - if you like or want endless amounts of volume in the well - then SET may not be your cup'a'tea. From the PP contingent, the argument is that SET amplification skirts or crosses the design "safety" margins for sound reproduction in too many areas to fully accomplish what is needed.

The whole scene is amusing. My Dynaco ST70 runs out of steam when I drive it hard, as I can hear the channel with the bass information getting "soft" at times as it runs out of juice. The other channel follows suit, chasing the tail. Given enough room, just about all our tube amps will show their limits. It is a question of how we set our listening paradigms, and the compromises we are will to accept. My most important listening feature is having the tubes covered, so Liam can't hurt himself Everything else is gravy...

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

You folks are still clueless. Volume levels always seems to be your fallback yardstick for measuring amplifiers or the quality of audio and musical experience. I'm happy that it works for you. At least one person recognizes;

"Moondogs may be able to avoid most of these pratfalls, but again, they are Moondogs, which most often have superior iron, design, and implementation."

EXACTLY! Well designed SET amps are more than qualified to get the job done.

There's more than math involved.

A snip from Arthur Salvatore's site may be food for thought, maybe not.

"Let's start with a speaker of fairly high sensitivity, which is the trend these days and also what I recommend above. Let's say the sensitivity is 90dB/1 watt. This means that at an 80dB loudness level, this speaker is receiving a total of 1/10th of 1 watt of power from the amplifier.

This is the point where most audio magazines stop measuring, but this is the exact point where they really should begin "fine measuring", because the 80dB is only the peak/accumulated loudness at that moment. All the real, fine musical details and information; the harmonics, decays, sense of space, dynamic inflections etc. are still 20 to 30dB (or more) below the 80dB peak.

What does this all mean?

The truly unique and distinguishing musical information is being reproduced with only 1/10,000 of a watt or even less power!

At a softer 60dB loudness level, which is not that unusual, the power level of even 1 Millionth of one watt becomes important!

Which audio "tech/guru" or scientist measures what is happening in an amplifier from 100th to 1,000,000th of one watt?

Answer: Not even one.

This same basic principle holds true for measuring preamplifiers, speakers and everything else. (It is also a very plausible explanation why some components appear to sound better after some "break-in".) Until it is possible to scientifically measure low-level musical information, we will have to trust our imperfect and unscientific ears and let them choose what component has the most "magic"."

Klipsch out.

[Deang]

"All the real, fine musical details and information; the harmonics, decays, sense of space, dynamic inflections etc. are still 20 to 30dB (or more) below the 80dB peak."

Really, so why do you insist on using an amp with no dynamic range? And you call us clueless?

[jazman]

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On 5/24/2004 1:34:46 PM DeanG wrote:

"All the real, fine musical details and information; the harmonics, decays, sense of space, dynamic inflections etc. are still 20 to 30dB (or more) below the 80dB peak."

Really, so why do you insist on using an amp with no dynamic range? And you call us clueless?

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

Poor baby,

You still don't get it. You confuse dynamic range with volume level. IF you have to push an amp to high volume levels to appreciate or hear the dynamics of the music, you've got a POS. One of these days, maybe the lights will come on.

Klipsch out.

[Deang]

Let me see if I have this straight: Low power means high detail and wide dynamic range, getting everything from 30db down to 30db up -- and high power just means "loud".

[neo33]

You got it, Deano baby! Took you that long to figure it out? .

[Amy]

Not everyone knows everything. Let's be a little nicer and a little less sarcastic when trying to educate our peers. I'm sure I could learn a lot from all of you (already am), but wouldn't be willing to listen to a condescending tone! I think it would make me instantly defensive...

[TBrennan]

Dynamic range is the volume difference between the softest and loudest sounds being reproduced. It's a spec, like 0-60mph or the quarter mile is with a car. It's objective and a function of efficiency, input power, compression and driver limitations. It's mechanical not mystical.

I've been using horn speakers for over 30 years and even fully horn-loaded speakers can use big power at times, even power on the order of 200 watts per speaker.

Now if someone chooses to use less power that's aces with me, I'm using a low-power gain-clone myself. Just don't kid yourself that your're getting all the dynamics if you are because you simply aren't. Period.

[Piranha]

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On 5/25/2004 9:11:50 AM TBrennan wrote:

Dynamic range is the volume difference between the softest and loudest sounds being reproduced. It's a spec, like 0-60mph or the quarter mile is with a car. It's objective and a function of efficiency, input power, compression and driver limitations. It's mechanical not mystical.

I've been using horn speakers for over 30 years and even fully horn-loaded speakers can use big power at times, even power on the order of 200 watts per speaker.

Now if someone chooses to use less power that's aces with me, I'm using a low-power gain-clone myself. Just don't kid yourself that your're getting all the dynamics if you are because you simply aren't. Period.

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

Tom, well put.

[maxg]

OK folks - I am still confused.

Now - bearing in mind Amy's instructions on Condecension....

Let me re-iterate the scenario keeping things as simple as possible and then let me know if a problem would occur using, for example, a 3.5 watt SET amp (a good one - lets assume - Moondog?).

I listen to music at relatively low levels. Even when "pumping it" the level never shows higher than 101 db at 1 meter from the speaker - going down to around 57 dB in the quiet bits (from memory).

AT THESE LEVELS, and running a speaker of, say 99 dB sensitivity or higher:

1. Would the amp ever clip? If so why? We are under the theoretical limits of the output, are we not?

2. Would the amp drive the bass similarly to my existing 70 wpc amp, better or worse (I realize you dont know what my amp does - but theoretically speaking is there a reason it might be worse?).

3. Would I expect said SET amp to have difficulty coping with sudden full orchestra entry from a quite passage (as, for example, can be found on a decent recording of Kimsky Korsakov Sheherazade) in comparison to a PP EL34 amp?

It seems from the posts in this discourse to date that the answers are Yes, no and yes - which confuses me greatly. If true - why do people use them? Just for this magic midrange? Too weird!

[Colin]

Nice post Andy,

I dont think it is the potential 40 watt output that makes one amplifier sound better than another flea-powered amplifier, it is the transformer and power supply to provide those 40-watts that can make some more powerful amplifiers sound better, PaulParrot doesnt like flea-powered SETS, but then, doesnt he have a huge listening room? Our advice has to be taken in the context of our own experiences, low power requirement is the essence of big ole horns

Max, you are looking at least 60% of an amp's output going to power the woofer.- sheltie, seems like a good argument for bi-amping

If the average, slow-weighted C scale music level is set at conversation levels of 75dB SPL for 1KHz as measured at the listeners seat in a moderate size living room and CDs have fast musical peaks of the same 1kHz frequency are only 15 dB higher, then ultra-sensitive (104 dB per watt per meter) classic Klipsch corner Khorns require only a two-tenth of a watt to reproduce 90 dB musical peak SPLs.

If you want to crank the average levels to 90dB, then the peaks require something like 3-watts. A flea-powered Bottlehead 2A3 Paramour monoblock actually puts out 6-watts, more than enough for the LOUDNESS required at 1kHz. How well this light little unit tracks the 40Hz bass wave at 100dB is another story.

Easy on the names, Deano

[sunnysal]

thanks amy for the reminder.

I have tried a variety of low and high powered amps with my k-horns, everything from 250 watts per channel SS (Classé, McIntosh, Pass Labs, etc.) down to 3-5 watts per channel SET (Cary, Wavelength, etc.), and a few in between (Dynaco, Marantz, LeoK, NAD, etc.)

I am willing to accept the possiblity that I MAY be losing some modicum of dynamics as tom has pointed out may be the truth.

I have chosen a modestly powered amp (PP2A3@10watts downwind) because I felt it gave me more "nuance" and better "soundstaging", more "warmth" (etc., etc.) than the high powered amps I tried, I still get all the volume I can stand when I want it but I enjoy the music my DHT low-powered amp makes more at more modest volume levels.

I did not choose an amp based on "relgious grounds", if I had I would have a system that consists of Halcro, TacT and B&Ws, I choose based on what made hair stand up on the back of my neck while listeing to my favorite music, what other criteria could I have?

In the end, what plays your music, in your room, with your other system components, the way you like it...is the right choice. IMHO. I did not enjoy my music, in my room, with my system as much with high powered SS as I did with low powered DHT, as they say YMMV and more power to ya!

Best amp advice, beg borrow (or steal) amps to demo in your system with you music, the right amp will make itself known.

warm regards, tony

[Cut-Throat]

I agree with SunnySal's post.

I have demoed and still own many kinds of amplifers in my home. I use the one that Sounds the Best with my Klispch Belles - That is the 1.8 watt per channel DRD45. When I play my inefficient 86 db speakers in other parts of my home, I use my other amplifiers. I have experimented with the other amplifiers on my Klispch Belles, but they do not measure up to the SET amps. You have to hear them for yourselves.

Some of the folks commenting on SET amps in this thread have never even heard a SET amp, yet feel compelled to pontificate on the specs of the amp. As someone pointed out here, it is the Iron also that makes a difference. You cannot judge an amp by specs alone. You really have to listen to it. I really don't care what the amp does on paper, I only care what it sounds like!

Another thing to keep in mind is that most folks that have SET amps, have had other more powerful amplifiers before. They rarely go back. There are a few folks that do (T Brennan), but they are mostly the exception.

[Amy]

Thanks, guys. It's more fun to seek help when you don't have to fear being made fun of

[neo33]

"Another thing to keep in mind is that most folks that have SET amps, have had other more powerful amplifiers before. They rarely go back."

My most powerful PP monoblocks produce a whopping 12WPC. Eversince I acquirred the 3.5WPC Doggies, I have never look back. My current two-channel audio gears (*) satisfy me for most types of music I listen to (classical, vocal jazz, classic rock) and I never turn the volume controls on my pre-amp pass 25% level.

(*)

Linn Axis TT --> AES PH1 --> AES AE1 --> Moondog SET Monos --> Klipsch Cornwalls

Jolida JD-100A CD Player -->

[Cut-Throat]

Neo,

So you got a pair of Moondogs? Which ones did you get? Do they have the magnequest or electraprint iron? Ultimate upgrade? They are really nice amps aren't they?

What kind of 2A3's are you running in them? If you have not already get some 5692 Red Base RCA tubes for them! They are stellar!

[neo33]

My Doggies have ultimate upgrade and MagneQuest OPTs. I am currently running them with RCA 2A3 Black-Plate and RCA 5692 Red-Base tubes. These tubes are a match made in heaven!

[ben.]

Why don't you change your profile?