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Old 19th January 2013, 08:57 AM   #8191
dvv is offline dvv  Serbia
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How about 2,000/3,600/5,400 Watts into 8/4/2 Ohms?

From experience, I know it will do more into 1 Ohms, but if the worst comes to worst, and it halves the power into 1 Ohm, that's still 2,700 Watts into 1 Ohm ...

Karan Acoustics, model KA M 2000. 40 Sanken RET BJTs at the output, 132.000 uF of capacitance, net weight 76 kg / 167 lbs.

Karan Acoustics | Manufacturer of High-End Audio

Drool, Wayne.

And investigate a direct link to the Hoover dam power station.
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Old 19th January 2013, 09:28 AM   #8192
dvv is offline dvv  Serbia
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There's an interesting point I'd like to raise on the subject of load tolerance.

Look at the schematics of any Harman/Kardon amp, and on the specs page, you'll find their statement on "HCC" ("High Instantaneous Currect Capability"), with numbers like 75 or more Amps. On the one hand, as such, that means diddly because it doesn't state any of the conditions, what load, what time interval, etc.

On the other hand, their quite commercial fare (in other words, serial products, not the up market Citation series), such as my own HK 680 (nominally 85/130W 8/4 Ohms, hardly revolutionary), are hard to believe when put on the test bench and made to jump through loops. With a time interval of 20 milisecs, as per the IEC standards, it kicked a very creditable 520 Watts into 2 Ohms.

And all this from a power transformer which, judged by the protection fuses, is around 500 VA, with separate windings for the left and right channel, and obviously, separate power supplies for each channel. These consist of a full wave bridge rectifier and two 8,200 uF caps. The supply lines are nominally +/- 52 V (off load). The actual output stage cnsists of a 5W predriver, 35W driver and two 130W output pairs. Global NFB is 12 dB.

So - how does one manage such power outputs from what is here a VERY modest power supply, apart from some quality engineering?
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Old 19th January 2013, 10:05 AM   #8193
fas42 is online now fas42  Australia
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Quote:
Originally Posted by dvv View Post
How about 2,000/3,600/5,400 Watts into 8/4/2 Ohms?
Wonder if those are continuous ratings ... the ME used continuously variable speed fans, with higher transformer rating and bigger, lower impedance capacitance bank. In a slugging competition the ME might just have the edge ...

Sorry, just doing some flag waving here, ...

Frank
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Old 19th January 2013, 11:30 AM   #8194
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[QUOTE=dvv;3331977]Actually, Nige, that may be some waystation, because in the end, the best overall solution is an active speaker.

Just imagine the bass or tweeter being connected to the driving amp by something like 10 inches of wiring of your choice, no resistors, capacitors or inductors in the way to cause nasty phase shifts and decrease natural driver efficiency, and so forth.

Under such circumstances, I believe some of the available all-in-one-chip power amplifiers would do just fine, possibly even very well. After all, they'd be seeing as clean and easy load as possible. ]

That's exactly the point . If one of the 100 watt chip amps was carefully matched to a tweeter with a high voltage supply is could be run well above the 1 V range where it will be mediocre . Run it at 20 V rms output potted down perhaps 20 to 1 and I think magic will happen . Just think how resistive the load would be . The divider perhaps 18 R and 1R . I see 20 V rms as an unlikely maximum . I suspect under normal working the resistors would be 17 watt rating . One could also try 6R of the load and 100 R . I doubt the Q of the tweeter a problem .

I have friends who endlessly search for the ideal tweeter . My guess is the ideal HF amp is more important ? One could use a valve amp . How wonderful to for once be liberated from the need for big iron . A mini Futtermans perhaps , like an all NPN transistor amp with for once the highly desirable high grade coupling cap/crossover ( 10 uF paper or whatever ) . Philips had such an amp in TV's . The speaker was 800 R from memory . With a bit of care I am sure 1 W can be had . I heard a Croft direct coupled valve amp once . It was very fast and good to listen to .

Best tweeter I heard apart from electrostatic was Red Rose ribbon tweeter . From what I know the Red Rose was a generic of a Chinese speaker . I like the very cheap Motorola pietzo's . They make good super tweeters . They need a crossover and made more resistive as a load . If they come in at 15 kHz that would be a good place to start . When listening to absolutely terrible PA speakers sometimes the HF still impresses and is missed in some expensive speakers . Even if a CD can only have 22.05 kHz the shape of the wave still would prefer the extra bandwidth .

http://www.st.com/internet/com/TECHN...CD00001887.pdf
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Old 19th January 2013, 11:48 AM   #8195
dvv is offline dvv  Serbia
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Originally Posted by fas42 View Post
Wonder if those are continuous ratings ... the ME used continuously variable speed fans, with higher transformer rating and bigger, lower impedance capacitance bank. In a slugging competition the ME might just have the edge ...

Sorry, just doing some flag waving here, ...

Frank
It's perfectly all right, Frank, it's a fair question.

Yes, those are continuous power ratings. The thing is a monster, I've seen and heard it, but not wanting any hernia, I never really tried to lift it.

What I cannot tell you is how long can it sustaing full power levels with sine waves.

My most delightful surprise overall though was that it sounds exactly like all other Karan amps, power and integrated, do. That's the one thing I take my hat off to Milan, all 6'6'' and 300 lbs of him, he has managed to keep his sound more constant and consistent than most out there in the High End. My KA-i180 integrated, delivering 180/250 WRMS into 8/4 Ohms, sounds exactly the same as that beast, only that beast has more of it to flaunt.

And yes, all his amps have that elusive exquisite feeling of limitless power, as if you couldn't overload it no matter what you do. It's an illusion, of course, but one I would gladly go for. Then again, given that the entry level with Milan is 22 dBW or 180 WRMS, perhaps I shouldn't be surprised. You DO expect 180 Watts to sound easy.

I've been friends with Milan for some 14 or 15 years, and I've never stopped marvelling when with him. He's a giant, literally, yet I don't get to meet such gentle people as he is. I'm passionate about music, but he's way ahead of me. You should see his lab playground, it's a sight to behold, lots of projects later rejected for some reason, yet fully functional. His home loudspeakers are based on JBL professional components and weigh in at around 110 kilos (250 lbs) each. Efficiency of some 96 or 97 dB/2.83V/1m, driven by his behemoth mono blocs, capable of 33 dBW, theoretically capable of music peaks of 129 dB. I mean, like, WOW!
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Old 19th January 2013, 11:58 AM   #8196
dvv is offline dvv  Serbia
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Originally Posted by nigel pearson View Post
That's exactly the point . If one of the 100 watt chip amps was carefully matched to a tweeter with a high voltage supply is could be run well above the 1 V range where it will be mediocre . Run it at 20 V rms output potted down perhaps 20 to 1 and I think magic will happen . Just think how resistive the load would be . The divider perhaps 18 R and 1R . I see 20 V rms as an unlikely maximum . I suspect under normal working the resistors would be 17 watt rating . One could also try 6R of the load and 100 R . I doubt the Q of the tweeter a problem .

I have friends who endlessly search for the ideal tweeter . My guess is the ideal HF amp is more important ? One could use a valve amp . How wonderful to for once be liberated from the need for big iron . A mini Futtermans perhaps , like an all NPN transistor amp with for once the highly desirable high grade coupling cap/crossover ( 10 uF paper or whatever ) . Philips had such an amp in TV's . The speaker was 800 R from memory . With a bit of care I am sure 1 W can be had . I heard a Croft direct coupled valve amp once . It was very fast and good to listen to .

Best tweeter I heard apart from electrostatic was Red Rose ribbon tweeter . From what I know the Red Rose was a generic of a Chinese speaker . I like the very cheap Motorola pietzo's . They make good super tweeters . They need a crossover and made more resistive as a load . If they come in at 15 kHz that would be a good place to start . When listening to absolutely terrible PA speakers sometimes the HF still impresses and is missed in some expensive speakers . Even if a CD can only have 22.05 kHz the shape of the wave still would prefer the extra bandwidth .

http://www.st.com/internet/com/TECHN...CD00001887.pdf
Nige, do take a long and hard look at RAAL - ADVANCED LOUDSPEAKERS .

That's one passionate dude, who's been at it for over 12 years now. His drivers can be found in several US made speakers, don't know exactly which, wasn't interested, but I know his main customers are in USA.

I don't have much experience with Aca's ribbons (BTW, his nickname locally is "Aca Ribbon" ), but I did spend a day at his home, to which he has added an entire auditorium, properly engineered for its acoustic properties, listening to his test speaker. It was a 2 way design, using a Volt bass driver, I think it was a 12 incher, and of course his ribbon. Not wishing to be some promoter of Serbian manufacturers, I'll say just this - that was the ONLY 2 way speaker I have ever heard which I would snap up for myself just like that and never look back. The clarity is astonishing.
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Old 19th January 2013, 12:14 PM   #8197
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From what I know ribbons were made from surplus radar magnets after the war . When the cheap source dried up so did they . The Wharfedale Isodynamic headphone was transformed into the Emit tweeter if rumor is right . Tandy ( Radio Shack ) sold a version . They resemble mini Magnaplanars . I feel CD made us less able to discern when a tweeter was more than just something to remind us of high frequencies .

Thanks for the links Dvv , plenty of reading .
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Old 19th January 2013, 02:39 PM   #8198
a.wayne is offline a.wayne  United States
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Quote:
Originally Posted by dvv View Post
How about 2,000/3,600/5,400 Watts into 8/4/2 Ohms?

From experience, I know it will do more into 1 Ohms, but if the worst comes to worst, and it halves the power into 1 Ohm, that's still 2,700 Watts into 1 Ohm ...

Karan Acoustics, model KA M 2000. 40 Sanken RET BJTs at the output, 132.000 uF of capacitance, net weight 76 kg / 167 lbs.

Karan Acoustics | Manufacturer of High-End Audio

Drool, Wayne.

And investigate a direct link to the Hoover dam power station.
Yes , Magic ! he is getting more power out than he is putting in ....
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Old 19th January 2013, 03:16 PM   #8199
gootee is online now gootee  United States
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Quote:
Originally Posted by dvv View Post
There's an interesting point I'd like to raise on the subject of load tolerance.

Look at the schematics of any Harman/Kardon amp, and on the specs page, you'll find their statement on "HCC" ("High Instantaneous Currect Capability"), with numbers like 75 or more Amps. On the one hand, as such, that means diddly because it doesn't state any of the conditions, what load, what time interval, etc.

On the other hand, their quite commercial fare (in other words, serial products, not the up market Citation series), such as my own HK 680 (nominally 85/130W 8/4 Ohms, hardly revolutionary), are hard to believe when put on the test bench and made to jump through loops. With a time interval of 20 milisecs, as per the IEC standards, it kicked a very creditable 520 Watts into 2 Ohms.

And all this from a power transformer which, judged by the protection fuses, is around 500 VA, with separate windings for the left and right channel, and obviously, separate power supplies for each channel. These consist of a full wave bridge rectifier and two 8,200 uF caps. The supply lines are nominally +/- 52 V (off load). The actual output stage cnsists of a 5W predriver, 35W driver and two 130W output pairs. Global NFB is 12 dB.

So - how does one manage such power outputs from what is here a VERY modest power supply, apart from some quality engineering?
Sorry to interrupt the very interesting ongoing conversation to go back to this.

It's actually easy to get that power level for such a short time, and almost couldn't be otherwise. And the 2 Ohms just makes it easier.

Starting at 0 watts, the no-load voltage would apply. So initially you'd get 52v/2 ohms = 26 amps. And 26 squared x 2 = 676 Watts.

And if the rail voltage was allowed to drop by 20 volts over 20 ms, then using

I = C dv/dt = .0164 • 20/.02 = 16.4 amps gives 16.4 • 16.4 • 2 = 538 Watts.

Parasitics and other things were ignored in those calcs but they're close-enough to see how it's possible.

Last edited by gootee; 19th January 2013 at 03:22 PM.
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Old 19th January 2013, 03:30 PM   #8200
a.wayne is offline a.wayne  United States
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Gootee ,

Dont we have to divide by 1.4 for rms output or not ...?
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