Jbl 4367

[KeithR]

Hmmm. I took a look at their web site. I don't see that good of distortion numbers there. The "F6" amplifier for example has 0.05% distortion at 1 watt. Here is the Mark Levinson 53:

At 1 watt, my eyeball says THD+N figure of 0.015% or three times lower than the First Watt F6 amplifier. The F6 is also rated at just 25 watts versus 500 watts for the 53.

Only a couple of their amps, the F5/F3 have 0.01% distortion which is not all that much lower than the ML. The rest are all worse.

With a picket fence of harmonics to go with it. You're missing the point- it's all about the first watt. The First Watt of a SIT-1 is much better than that of any digital amp. And with high efficiency speakers, he doesn't need 500 watts.

And the ML 53 doesn't sound very good, so there's that too. And I think it's funny you think 0.05% distortion is high, but that's really besides the point.

 

[KeithR]

Where's the insults? I was just pointing out some facts about skeptics of flat screen TV's about 15 years ago and it reminds me what a lot of people have to say about class D today. But your post is a great example of one. I support innovation. The problem with some class D like the Mola Mola Kaluga is it's too good. So now to take things up a notch, things have to be backed down a few notches and coloration's must be added to satisfy many. Bruno's quite stubbornly against it, but other's are realizing it's the only way to satisfy some.

I've had 16 amps on high efficiency speakers in my home including digital amps. Where is your comparable experience?

 

[KeithR]

Have you heard Devialet? Lovely warm sonic signature like a Class A amp has but with the control of a Class D.

Nyal, I've only heard the D Premier not the newer stuff - I wasn't impressed at all on two systems (Focal and Martin Logan). That said, I've never had one in my home and I don't know if the newer versions are better.. I did not find it class A sounding at all - and I've had several of those at home, both SS and tube.

 

[Blizzard]

I've had 16 amps on high efficiency speakers in my home including digital amps. Where is your comparable experience?

Which amps were they? What did they use for input buffer stages?

I've been building class D amps for 9 years now. And class D amps aren't digital amps. If you were using digital amps, then that was likely the problem.

 

[KeithR]

Which amps were they? What did they use for input buffer stages?

I've been building class D amps for 9 years now.

Nuforce. I've also heard Mola Mola several times, just not in my system.

I also just heard the new Spec amp last weekend - I'll give you more feedback on that one in a few weeks after I hear it again. It was a new speaker that I was unfamiliar with.

So you've never heard digital amps on high efficiency speakers- no surprise.

 

[Blizzard]

Nuforce. I've also heard Mola Mola several times, just not in my system.

I also just heard the new Spec amp last weekend - I'll give you more feedback on that one in a few weeks after I hear it again. It was a new speaker that I was unfamiliar with.

So you've never heard digital amps on high efficiency speakers- no surprise.

So you are comparing the cheap crappy Chinese Nuforce amps with real class D amps?

A little lesson on class D amps:

http://www.hypex.nl/docs/papers/AES124BP.pdf

 

[KeithR]

So you are comparing the cheap crappy Chinese Nuforce amps with real class D amps?

A little lesson on class D amps:

http://www.hypex.nl/docs/papers/AES124BP.pdf

So you haven't heard digital amps on high efficiency speakers.

I don't need lessons on amps, thank you.

 

[Blizzard]

So you haven't heard digital amps on high efficiency speakers.

I don't need lessons on amps, thank you.

The problem was the amp you were using, not the fact that it was class D.

You must need a lesson if you call them "digital amps"

If you want a class D amp that will outperform the Nuforce it's not hard to find. Here you go:

http://www.parts-express.com/sure-e...250w-irs2092-class-d-amplifier-board--320-313

 

[amirm]

With a picket fence of harmonics to go with it. You're missing the point- it's all about the first watt. The First Watt of a SIT-1 is much better than that of any digital amp. And with high efficiency speakers, he doesn't need 500 watts.

The distortion figures I showed were for the first watt. The first watt distortion from that company was 3.3 times higher than the class D (really call I) amp at the same 1 watt output. So what is it that I am supposed to get?

And the ML 53 doesn't sound very good, so there's that too. And I think it's funny you think 0.05% distortion is high, but that's really besides the point.

I didn't say it was "high." I said it is 3.3 times higher than class D amp. Any time you want to put that amp against the 53, I am here here for you .

 

[amirm]

So you haven't heard digital amps on high efficiency speakers.

I have. I have driven the JBL Everest with them. What is the question regarding that?

 

[Blizzard]

The distortion figures I showed were for the first watt. The first watt distortion from that company was 3.3 times higher than the class D (really call I) amp at the same 1 watt output. So what is it that I am supposed to get?


I didn't say it was "high." I said it is 3.3 times higher than class D amp. Any time you want to put that amp against the 53, I am here here for you .

I guess the 1W THD+N of 0.0005% on the NC 500 is a deal breaker as well. 100X lower distortion at 1W than the first watt.

 

[KeithR]

The distortion figures I showed were for the first watt. The first watt distortion from that company was 3.3 times higher than the class D (really call I) amp at the same 1 watt output. So what is it that I am supposed to get?


I didn't say it was "high." I said it is 3.3 times higher than class D amp. Any time you want to put that amp against the 53, I am here here for you .

Incorrect analysis- with your amp, you get a picket fence of odd-order harmonics and THD distortion highest at the lowest output, together. with (some) First Watts, you don't.

If all you care about is THD, go run and buy yourself a QSC or Crown amp with a zillion dbs of negative feedback and infinitesimally low THD.

The great thing about high efficiency speakers is trying low power, simple amps with fewer gain stages, transistors, etc - but if you as a dealer for ML don't want to, that's totally your prerogative.

I also find it amusing you quote 60k digital amps against amps < 10k, but that's another story.

 

[Blizzard]

Come to think of it I recently had my NC500 based amps hooked up to a pair of unison research Max 1's. Only 94db efficiency, but still a very revealing horn loaded compression driver with titanium diaphragm. Not exactly the most forgiving driver in the world. Sounded extremely good actually. Awesome dynamics. Lightyears better than their Sinfonia amp. The sinfonia amp had an annoying buzz in the background, and a very high noise floor. Distorted like hell when pushed as well. Very unimpressive amp to say the least.

http://www.unisonresearch.com/en/products/loudspeakers/max-1.html
http://www.unisonresearch.com/en/products/valves/integrated-amplifiers/sinfonia.html

 

[KeithR]

Come to think of it I recently had my NC500 based amps hooked up to a pair of unison research Max 1's. Only 94db efficiency, but still a very revealing horn loaded compression driver with titanium diaphragm. Not exactly the most forgiving driver in the world. Sounded extremely good actually. Awesome dynamics. Lightyears better than their Sinfonia amp. The sinfonia amp had an annoying buzz in the background, and a very high noise floor. Distorted like hell when pushed as well. Very unimpressive amp to say the least.

http://www.unisonresearch.com/en/products/loudspeakers/max-1.html
http://www.unisonresearch.com/en/products/valves/integrated-amplifiers/sinfonia.html

sounds like a bad tube or broken amp- what a comparison lol.

 

[Blizzard]

sounds like a bad tube or broken amp- what a comparison lol.

No the dealer assured me that's just how they sound and there was nothing wrong.

 

[KeithR]

No the dealer assured me that's just how they sound and there was nothing wrong.

well, duh. he's trying to sell you an amp.

why don't you send me a pair of your homegrown amps - I'll do testing and post up on the forum. deal? Steve Williams can vouch for me, and in fact can join me for a demo. He didn't choose the Mola Molas over his Lamms FYI

it will be on 101db efficient speakers with no crossovers - easiest speaker in the world to compare amps with.

 

[Blizzard]

I also find it amusing you quote 60k digital amps against amps < 10k, but that's another story.

What you need to spend over $10K to get good performance out of class D?

100X better 1w THD+N than your first watt amp performance appears to be available for only $1995. For a pair of mono blocks no less.


http://www.tweekgeek.com/acoustic-imagery-atsah-500/

 

[amirm]

The great thing about high efficiency speakers is trying low power, simple amps with fewer gain stages, transistors, etc - but if you as a dealer for ML don't want to, that's totally your prerogative.

I am a dealer for audio science. And audio science says efficiency numbers are marketing values. A big woofer in a speaker needs a ton of power. It doesn't care how efficient the compression driver is where efficiency is measured and put on the spec sheet. Unless you have efficiency number for below 500, forget about using them to figure out how much power you need.

That is why I said your low power amp can be beat and beat easily because it can easily be pushed into distortion with the type of speaker we are talking about.

Now if you have a speaker that has a wave guide for the woofer, and therefore is the size of a refrigerator, then sure. You can use low power amps. Don't confuse the two.

 

[Blizzard]

well, duh. he's trying to sell you an amp.

why don't you send me a pair of your homegrown amps - I'll do testing and post up on the forum. deal? Steve Williams can vouch for me, and in fact can join me for a demo. He didn't choose the Mola Molas over his Lamms FYI

Some people like the distortion of tubes.

 

[KeithR]

Some people like the distortion of tubes.

and some like the odd-order distortion of digital amps.