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Old 10th December 2007, 11:12 PM   #1
vizion is offline vizion  United States
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Default non-NFB buffer

hello,

has someone come across a buffer with no NFB ?

thanks.
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Old 10th December 2007, 11:13 PM   #2
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Does an emitter/source/cathode follower meet your "no NFB" criteria?
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Old 10th December 2007, 11:16 PM   #3
vizion is offline vizion  United States
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it's something to hop on. do you have the details ? isn't there usually global feedback with that combo ?
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Old 11th December 2007, 01:05 AM   #4
Leolabs is offline Leolabs  Malaysia
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JFET follower loaded with JFET current source.
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Old 11th December 2007, 01:35 AM   #5
vizion is offline vizion  United States
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Leolabs,


do you have schematics or a link ?
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Old 11th December 2007, 01:55 AM   #6
mlloyd1 is offline mlloyd1  United States
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search for the Hafler 915 preamp manual at the Hafler web site.
also, numerous links on this site via search function.

mlloyd1

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Originally posted by vizion
Leolabs,


do you have schematics or a link ?
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Old 11th December 2007, 01:56 AM   #7
CBS240 is offline CBS240  United States
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Q1 is a Jfet follower and is biased with a constant current because R4 will always have Vbe of Q3, or 0.6V across it. P1 sets DC bias, Q2 is the self bias J-fet CCS. Regulated PSU is a must. Just a quick thought.
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Old 11th December 2007, 02:25 AM   #8
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Default Re: non-NFB buffer

Quote:
Originally posted by vizion
has someone come across a buffer with no NFB ?
If you're looking for a ready made (chip) solution, here are a few:

National LMH6321
Burr-Brown BUF634
Burr-Brown BUF600/601 (discontinued, but still in stock at some distributors)
Maxim MAX4200 through MAX4205

Or you can roll your own.
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Old 11th December 2007, 02:29 AM   #9
vizion is offline vizion  United States
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Larocco Audio used to carry a dynamically biasing triad diamond buffer with no global feedback. not in production anymore
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