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Old 27th September 2012, 04:33 AM   #1
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Default Motional feedback amplifier based on Philips 40 wats amplifier 1970s

Hi all
I fond Motional feedback amplifier when i browsing it make some changes in original Philips 40 wats amplifier lat 1970s
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Old 27th September 2012, 08:12 AM   #2
troystg is offline troystg  United States
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Are you going to build it and if so what driver / box is it designed for?
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Old 27th September 2012, 09:27 AM   #3
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Hi am build the old version a philips 40 WATS 1970s but this one is better because very low distortion original is also very good i used 10" woofer 1" tweeter shield enclosure
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Old 27th September 2012, 09:38 AM   #4
troystg is offline troystg  United States
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So you used it full range? Why not bi-amp and use only on the low section? Is there any benefit to the tweeter / HF section?
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Old 27th September 2012, 12:06 PM   #5
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HI i prifard to use tweeter & woofer because this amplifier don't need passive filter with tweeter hi frequency response is very good can you give me some suggestion about this amlifier
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Old 27th September 2012, 01:00 PM   #6
troystg is offline troystg  United States
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I don't know what you mean by suggestions, but to me a motional feedback amplifier would be used in the LF section of a bi-amped speaker.

I use a negative feedback electronic suspension system designed by Mr. Erath.
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Old 18th May 2013, 07:24 AM   #7
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Quote:
Originally Posted by sanbadgujar View Post
HI i prifard to use tweeter & woofer because this amplifier don't need passive filter with tweeter hi frequency response is very good can you give me some suggestion about this amlifier
I know that this is old thread...

but could you elaborate why/how this amplifier don't need passive filter with tweeter hi frequency? is it because you have two seperate amp for low and hi part? (bi-amping with active x-over or passive network in front of the amp?)
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Old 18th May 2013, 07:35 AM   #8
Zero D is offline Zero D  United Kingdom
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Quote:
Originally Posted by dw1narso

but could you elaborate why/how this amplifier don't need passive filter with tweeter hi frequency
Maybe he's using a piezo HF ?
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Old 19th May 2013, 01:31 PM   #9
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piezo HF? hm... don't really like it except for filling the air with really high frequency spectrum...

or I suspect that he use another capacitor coupled tweeter in parallel with the woofer? Which is actually doing 1st order filtering...
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Old 5th August 2013, 10:01 PM   #10
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This basically a schematic of a simple (typical) Class AB amplifier design that uses current feedback instead of voltage feedback via the .47ohm resistor in series with the output load to ground and the 470ohm resistor going back to the input transistor.

It appears that the motional feedback section had not been implemented yet.

FWIW

jer
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