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Old 26th September 2002, 10:01 PM   #1
rickpt is offline rickpt  Portugal
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Thumbs up halcro amplifier

Hello
I was reading the halcro amplifier patent. It claims ultra low distortion.
Anyone want to comment?
Link: http://patft.uspto.gov/netacgi/nph-P...lcro&RS=halcro

The amp has excellent reviews on stereophile...

maybe a diy hould be feasabale

Regards

Ricardo

(Ps: I cannot see the images on the patent web site... how can I see the images?)
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Old 26th September 2002, 11:11 PM   #2
herm is offline herm  United States
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I had to go to:

http://www.alternatiff.com/

and download their program to see the images.

I am not sure if you have to do this, but it worked
for me....
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Old 26th September 2002, 11:27 PM   #3
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I had a chance 2 weeks ago to bench test one of these
units. On my equipment they do not quite meet their
specs, yet .0008 thd at full power at 20khz is not an
easy thing to do.

On my wilsons, they have a lack of bass. Partially due
to the current limiting.

They have 6 p channel and 6 n channel vertical fets for
the output transistors. They are uniquely built to say the
least. The universal input power factor corrected high
frequency supply is also interesting.

The add/subtract around the output stage looks like a
more complicated version of the seal electronics amp.

The stereophile and absolute sound reviews of this amp
both have discrepancys, like the fact that the amp has
no overall feedback. The amp does in fact have global feedback
in addition to local feedback loops.

I don't like Bruce Candy's attempted secrecy about various
circuits, never did like high falutin mumbo jumbo. The patent
however tells most of the tricks...

Doing the add/subtract around the output stage with
bipolar transistors would be much more work.

I would take a krell or levinson monoblock over these anyday.

How about some discussion about the design aspects...
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Old 26th September 2002, 11:33 PM   #4
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Exclamation HHmmm...

...got funny feeling someone has gone and patented Prof. M.O.J Hawksfords idea on error correction...this was used in robert cordells JAES paper sometime in the '80's....check out JAES website..
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Old 26th September 2002, 11:50 PM   #5
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Default Halcro!!

Hei mikeke

Now we are two with the same feelings ...

When i see the patent i also nailed the output stage with error correction...of M.J.Hawksford in his work(Distortion Correction in Audio Power Amplifiers...65thConvention of The Audio Eng. Soc.)..
.
And the idea of bootstraped power suplyes .is also used in the Audio Analog Amplifiers....


But!!!...maybe i have only a souspicios mind!...

Regards

Jorge Santos
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Old 26th September 2002, 11:56 PM   #6
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Smile Hi jorge..

You are absolutely correct.....amazing how people can get away with patenting someone elses idea that has been public domain for near 20 years...

Mikek in essex...uk.
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Old 27th September 2002, 12:06 AM   #7
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Default mikek

I see one aplication of the output stage with error correction of M.J. Hawksford in a amplifier ...and it show a full power 500kHz square wave into a 8 Ohm load!...Realy amazing!!!...

Good design!!!...

Cheers


Jorge Santos
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Old 27th September 2002, 06:51 AM   #8
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Can anyone tell me why it's hard to get patent information? With the Mac program Patent Grabber you can download, pdf, tiff of text easy. Why?
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Old 27th September 2002, 06:58 AM   #9
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Default patents

I have no trouble reading it online. I think they want you to PAY for a hard copy.........

H.H.
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Old 27th September 2002, 06:59 AM   #10
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