The Ultimate KHorn Amplifier .... Is there one?

[Erik Mandaville]

"He is talking about his choice... when he says "over here" he is referring to his own own home and his own system. And I'll bet he's heard/owned just as many amps as you have..."

No need to bet, Mike. Chances are he's probably owned more amps than I have.

Erik

[Erik Mandaville]

Dean:

"The kind of post you might write out for a guy whose only been doing this a year or two, really Erik."

That's what's needed, I think. There are times we complicate things to the point of not only discussion, but extreme argument, name calling, mean pictures, and so forth. All the bad things. People have been told they didn't know what they were talking about, or were deaf, simply because they may not have been able to hear a difference between one kind of capacitor and another in a crossover. An amp is just another part of the chain, and I was sincere when I mentioned the listening to some different examples -- as you have, as I have, as many of us have -- before selling in order to get something else to try for a hopefully better result; which you know as well as I, Dean, can sound good on one day, and just completely wrong on another. And then we sell in order to fish again in another pond.

And when I asked the question "Really" to what you said about the VRDs being the best all 'round performer, I meant do you really think that (?). I remember how lousy you thought the Wright 2A3 amps were, but I truly (honestly!) wish you could have heard them on another occasion. I truly think they were not working quite right at the time you listened to them. low power SET is obviously not everyone's cup of tea, though. Fair enough.

Back to the tone of inexperience you mentioned. I have to say, and I really believe this, that some of the most accurate, poignant, and completely honest reviews of the sound quality of different audio components have come from those who are very dedicated music listeners rather than technicians; and for some reason, more often than not, they are guys/gals who are devoted to vinyl playback. It's sort of an odd coincidence, but that is the case. For example, I remember a 7th grade student of mine who commented after a weekend that he had the chance to listen to his dad's good stereo system. All vinyl. He said he thought that 'records' made his CDs sound like 'cardboard cutouts'. I should mention this student was also already a talented musician, but was just so sincere in this assessment that it made an impression on me.

I wasn't referring to you when I used the word 'you,' by the way, but I can see how you might have taken it that way. I meant 'one,' as in "The best one, after one has had the chance to compare different types, power ratings, vintage/modern, output device, and that sort of thing. I've gotten to know you well enough as a forum member to know that you've had plenty of opportunities for that, and was directing that comment to the original author of this thread.

I had always wanted a pair of Welborne Apollos, by the way, and I remember the main reason at that time had to do with the fact that my wife and I both thought they looked really cool.

Erik

edit: TS OTL? (ah, I just now understood. Transcendent Sound OTL. I was thinking that was some other model or brand, or something). They are good sounding amplifiers.

[rigma]

"Most amplifiers that sound bad at 10W sounds just as bad at 100mW or 10mW."

I don't know about that one. You said "most", so I'll let you slide.

"I invite anyone with an RS SPL meter and a CD with a constant tone test track to try this. In the mid frequencies, say 1000 to 4000 Hz, 75 dB is comfortable, and 85 dB is getting loud. Comments?"

I agree with that. Two things here, 1) people who listen "loud" most of the time might consider 75dB down too far to bother with and 85dB "comfortable". People who listen at low levels most of time might consider 85dB fairly loud. 2) A person who has some loss in their hearing would certainly not qualify 85dB as "getting loud". I've seen posts where 100dB was described as "comfortably" loud.

If we contain the discussion to big Heritage, I agree with Gil.

"The Chorus II is rated to be 101dB with 2.83V at 1 meter."

No, it's rated 101dB @ 1 watt. The Chorus II impedance goes well over a hundred ohms, where you would need 10 volts to get a watt.

"Ultimate" Klipschorn amplifier? Though some around here think I've tried every amplifer ever built, there's plenty I haven't heard. All around best performer over here has been Craig's VRDs. If you don't need the power and don't have the wallet, Tripath gets scary close. The best amp I think I've ever heard was Rigma's Angela 91 monoblocks, but those were on Jubilees, so hardly an apples to apples comparison.

Wow Deano, I just saw this. Thanks for the compliment and glad you liked them so much. They do mate very well with the Jubilees but they also sound great on my Khorns but I can't go back the them after the Jub's.

rigma

[jt1stcav]

Here's the best amp for your Klipschorns...no sense debating the issue![]

[jt1stcav]

Just joking...

As others have stated, what sounds best to your ears is what's best for your horns. And it could very well be solid-state or digital as well; it doesn't have to be tube driven.

[DrWho]

I missed this earlier...

"The Chorus II is rated to be 101dB with 2.83V at 1 meter."

No, it's rated 101dB @ 1 watt. The Chorus II impedance goes well

over a hundred ohms, where you would need 10 volts to get a watt.

How do you propose the 1 watt be measured when the speaker is

connected? You would need to measure the current, voltage, and the

power factor in order to obtain a meaningful power measurement...and

even then, how does one determine which frequency determines the SPL at

that power?

Not to nitpick, but I'm pretty sure that when something says that it's

measured at 1W, it means the voltage that correlates to the nominal

impedance in the spec sheet...so for an 8ohm nominal speaker that's

2.83V. For a 4 Ohm speaker, that's 2V. Since higher sensitivities are

usually a good thing, most manufacturers will use 2.83V into a 4 Ohm

load so that it reads 3dB higher (but that's also not a big deal since

most amps can drive 4 Ohms and will double their power output when

doing so). A 16 Ohm speaker will benefit from a 1W rating because it

means they can put 4V at the output of the amp instead of only 2.83V

(also making it seem 3dB higher). Ultimately, the only thing that

matters is how loud the speaker is for a given input voltage since

audio amplifiers are amplyfing the voltage. The actual power consumption is really just a result of what happens when the voltage is present.

[Deang]

Punk kid.

You said that your experiment meant that there must have been about 26dB in transients with your test song, I'm curious what song you were using. I don't think I'm ready to rate something like the Chorus II at 75dB/watt with music, which would mean well over a 100 watts to get 100dB of output. Of course, you can easily get that with 30, so something is terribly wrong here.

[DrWho]

We're using two songs hardcore in the lab right now....Piano Man by Blue Man Group and then Mummer's Dance by Loreena McKennit.

If it helps you wrap your head around it, I think the discrepancy

you're commenting on is the result of lag in the SPL meter reading.

When a sharp transient happens, the needle on the meter isn't able to

move quick enough to show the behavior - so before the needle gets up

all the way, the voltage is swinging the other direction causing the

needle to read lower than the real acoustical output. There is all

sorts of talk about "meaningful metering" (I think that might even be a

title of an article), which discusses the delays associated with meters.

The point I was trying to make earlier is that people associate SPL of

music to the meters they're using - so basically, when anyone measures

how loud they listen, there is the possibility for transient peaks that

don't show up on the meter. If this is true, and people are using

amplifiers without enough watts to handle the transients, then the amp

is clipping. Depending on how the amp clips, one might be able to call

it a compressor/limiter - which I think would explain a lot of the

intimacy and increase in detail so often touted. It would also explain

some of the things that happen to the bass too...

Anyways, it's just a theory and one of these days I intend to start

quantifying the clipping behavior of amps to see if there aren't sonic

trends (in which case, it would always be beneficial to create a

product that clips "nicely").

[Wrench722]

What about the McIntosh 2102?

[PrestonTom]

If you suspect the meter ballistics of an analog meter are too slow, use a digital meter. There's nothing that can be produced by a mechanical speaker that can't be tracked by a digital meter.

I am not so sure about that.

Certainly, the ballistics on analog meter are acting as a low pass filter on the read-out. However, going to a digital meter will not be the final answer. There will again be a functional low pass filter on the read-out. This may be described as a windowing or integration time, but it will not give near-instantaneous values. This is pretty much required or else the read out (numerals) would be bouncing all over the place and it would be impossible to read anything at all in most circumstances. I doubt that the integration time is faster than the bandwidth of the speaker

Mike's idea at looking at the actual waveform (amplitude, or voltage, vs time) gets us a bit closer if you can freeze it (not continuous on an o'scope). However, to get us back to power we would need to square the values and divide by the impedance. The problem here is that the system does not have a constant impedance as a function of frequency (far from it) nor will it necessarily have a flat frequency response (but that is a smaller problem). So the problem when you see the waveform skyrocket above the steady-state on some transient, is knowing the the frequency region that is most affected (and what its local impedance is).

On top of all this one would want to know whether the amp is clipping on a transient due to a lack of instantaneous voltage (exceeding the voltage on the rails) or whether it was due to lack of transient levels of current (especially at the low frequencies where the impedance presented by the speaker might dip down quite a bit).

BTW, Mike shame on you for even suggesting that certain kinds of clipping might actually be a good thing. Clipping is bad, period. Certain kinds of clipping may not be as aversive, but it is never a desirable thing. The goal is accuracy, free from clipping. It is not how to produce "nice clipping"!

Good Luck,

-Tom

[Coytee]

What about the McIntosh 2102?

They suck... trust me on this as I own one and can speak from experience. Listened to it on LaScalas, Khorns, Academy's and of course, Plug Uglies.... sucks on them all.

So, anyone else that has one (or the MC-2000 FRITZIE!!) can just send them to me for the trashy value they're really worth...

[]

[jacksonbart]

I think one of these would do it.

[NOSValves]

Are there so many people who can't hear amplifier clipping?

For ultra quick transient peaks I think most have no idea if the amp is clipping especially when you factor in the smooth clipping character of many of the amps used around here. Many believe their favorite amp is not clipping just because it can play objectionably loud when in reality it is so congested from being over driven that it in turn drives them out of the room. Been there seen, heard and witnessed it time and again.

Craig

[DrWho]

BTW, Mike shame on you for even suggesting that certain kinds of clipping might actually be a good thing. Clipping is bad, period. Certain kinds of clipping may not be as aversive, but it is never a desirable thing. The goal is accuracy, free from clipping. It is not how to produce "nice clipping"!

Oh I agree completely! I would never consider it acceptable to listen to any kind of clipping - pleasnt or not. However, I still think it is good amplifier design to ensure that when clipping does happen (and I think it's fair to assume that it will always happen at some point), that it shouldn't sound awful. If anything, it's more of a marketing perspective than a purist perspective...

[DrWho]

This is pretty much required or else the read out (numerals) would be

bouncing all over the place and it would be impossible to read anything

at all in most circumstances.

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

I

think most have a peak hold feature. For most designs I've seen, the

input capture circuits and A/D, and the display are functionally

different blocks. You can decouple the display characteristics from the

input sample and hold in pretty much anyway you want.

So is that what you would do if commenting on SPL?

I think a quick trip around the audio world will reveal that most

people are using normal analog SPL meters...in which case, most people

can't tell whether or not their amp is clipping when using an SPL

meter. And without an SPL meter, one cannot correlate how loud any SPL

is...so basically, the transient SPL's are

actually a lot louder than would otherwise be correlated to the SPL as

measured by an SPL meter. There wouldn't be general rules of thumb in

the professional audio world if this weren't the case - there are no

shortage of articles explaining that you need to add 10-20dB to the

output measured by a needle. I might also add that I've had digital and

analog meters side by side and they operate much how Tom

describes....they integrate at about the same speed as a needle so that

the numbers don't jump around. You still have the integrator in the circuit

when setting the meter to peak hold. There is also the issue of power

compression in the speaker, which will make the calculated power be

less than reality.

Anyways, the important thing is how current SPL meters work and the

numbers people associate with what they hear...not how they could work.

For what it's worth, I like using analog SPL meters because you know that the maximum rate at which the needle falls is the maximum rate at which the needle rises....so you can get an idea when a transient is way louder than you might have expected. I think an interesting experiment would be to record a signal that is -20dB and then throw in a few rim shots recorded at 0dB. I bet you won't see the needle move more than 6-10dB depending on the speed of the meter...

[Deang]

Are there so many people who can't hear amplifier clipping?

I guess the answer is no. You need a scope, a couple of meters, and then run a few calculations before you make your way over to the VC.

[jt1stcav]

Oh, I can definately hear my 8 watter clip when I'm over 95dB levels! But boy, isn't that clipping oh so wonderful and smooth sounding.[]

[Wrench722]

What about the McIntosh 2102?

They suck... trust me on this as I own one and can speak from experience. Listened to it on LaScalas, Khorns, Academy's and of course, Plug Uglies.... sucks on them all.

So, anyone else that has one (or the MC-2000 FRITZIE!!) can just send them to me for the trashy value they're really worth...

[]

I though Mc was the best? [*-)]

[Coytee]

Well Wrench, if you're being serious...

I've had MC amps on my stuff and can find NO fault with them at all. I'd venture to say that anything you've heard about them would be accurate.

I will also go on to say that after having heard various amps (Wright 2A3, MC-30's, MC-2102, Transcendent SE-OTL, Crown K2, dbx BX1, dbx BX3) in my system...

The ONE amp that I keep thinking about (sort of like a fond memory of an old girlfriend and how everything she did was just a bit different and per perhaps faulty memory, "better" than any current girlfriend)

Anyway, the amp I keep thinking about were the Transcendent SE-OTL's. I've sold the Wrights, MC-30's, BX1 is on the way out and I keep thinking I might pick up the SE-OTL's (since I'm biamping) or maybe their larger brother since I'm a volume nut. I don't know for sure if I could live with the 4 wpc two bridged SE-OTL's would give me for the times my wife isn't home....iffen ya know what I mean.

Heck...I'm not even sure the larger T-16 would have enough oomph for those times.

For the SONIC sound though, the OTL amps stay in my mind as something different and in my mind, it was a GOOD difference. Even my wife and her sister happened to (ironically?) make comments about how nice the sound was and interestingly, the ONLY time they've ever made that unsolicited comment is when I had the SE-OTL's wired up. For them to make that comment (they hate anything larger than bose cubes) was a real change of gear for them because their ONLY comments are usually "those are big teenager speakers that are passe' and NO ONE buys things like that anymore"

I'm wondering if I'm evolving into an OTL fan... [:^)]

[Tarheel]

Just got the November issue of Stereophile mag. Sam Tellig interviews Mike Sanders about his new Quicksilver Audio SET mono amps. 9 watts and $2800 and a very handsome amp. Mike listends through LS last time I talked with him. The wheels are turning.....trade him my horn monos for the SETs? Go from 25w to 9w?