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MoonWatcher
Bronze Member
USA
98 Posts |
 Posted - 09/21/2008 : 02:10:47
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Hey folks -
BD-2 mods are nearly complete, but the op amp is still getting slammed with a bit too much signal, and I can't attenuate the FET stages any further without dulling out the tones...
I need a dual op amp that can take a POUNDING. The higher the input impedance, the better, so that the op amp stage basically becomes a super buffered recovery stage, and nothing more.
I was thinking of the TL0XX series of chips, but I'm sure there has to be something with an even higher input impedance. I'm convinced that the slew rate, gain bandwidth product, etc. aren't critical - it's keeping that chip from clipping that is!
This has got to be the last piece of the puzzle.
-MW |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 09/21/2008 : 14:06:44
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Hi MoonWatcher
I read your post early this morning, & have been thinking about your question all day, well amongst other things.
AIl I can come up with, is the Old CA series of Hi-Imp op-amps.
I think they were manufactured by RCA, & a few other companies under license.
CA30xx series,
I believe some were even FET input stages, we used to use them in/as instrumentation amplifiers,
You can still find them, If you look around a bit.
Have you considered the 5532 5534's?
Regards Dr. Bob |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 09/21/2008 : 17:45:45
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| Yeah... been thinking about it too and can only come up with TL072 - the input resistance is HUGE and the offset current etc are tiny, so it should be close to as good as you will get. |
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Highest input impedance dual op amp?
