Fantastic P.I front end building block

[Max]

The Wizards design is common similar circuit from elecktor old edition 1997 or older in parallel using LT1028 too. Or use low noise opamps cooled by liwuid nitrogen or helium....

You can do the same with e.g. OP27 and similar to gain same noise level... and you don't need any liquid nitrogen to get it work.

(also cause mil range is from -55 °C and not less than this... and if you use liquid nitrogen you'll be lost in space... at atmospheric pressure, it boils at −196 °C... lot of troubles... and stuff cracks due to thermal gradient from inner and outer of them)

[TheWizard]

This is not my design...
This is example from PMI 1986 catalog...

Precision Monolithics Inc - now Analog Device

[Woody.au]

Doc was too big ..bugger.

[Woody.au]

I have uploaded front end designs to a site I have, PDF is 2.67 Megs so it may take a while to load.

The front end design is near identical to what Candy did for SD2000 and 2100 so I think he got it out of the book.

http://app4.websitetonight.com/proje.../low_noise.pdf

[sharky]

This is not my design...
This is example from PMI 1986 catalog...

Precision Monolithics Inc - now Analog Device

I think using low noise transistors can achieve a better result, why use opamps

[sharky]

You can do the same with e.g. OP27 and similar to gain same noise level... and you don't need any liquid nitrogen to get it work.

(also cause mil range is from -55 °C and not less than this... and if you use liquid nitrogen you'll be lost in space... at atmospheric pressure, it boils at −196 °C... lot of troubles... and stuff cracks due to thermal gradient from inner and outer of them)

Our deep sapce probes run at -196 °C, use an aero grade one

[sharky]

Why do you always use such short lines when you type?

Elie seems to be te only lady in this projects...wonder where other girls are, this seems to be a man project

[Elie]

Elie seems to be te only lady in this projects...wonder where other girls are, this seems to be a man project

I am a man.

[Woody.au]

I am a man.

ROTFLMAO

[Mr. Bean]

OP 27

You can do the same with e.g. OP27 and similar to gain same noise level... and you don't need any liquid nitrogen to get it work.

(also cause mil range is from -55 °C and not less than this... and if you use liquid nitrogen you'll be lost in space... at atmospheric pressure, it boils at −196 °C... lot of troubles... and stuff cracks due to thermal gradient from inner and outer of them)

Hi Max,

The op27 is an old story, I have about 10 here from years

ago. It is low noise, problem is it doesn't recover fast

enough from saturation.

Of course all this sillyness about noise assumes there is

not a larger external or internal noise source {micro/digital}

booming away alot bigger than nice gaussian noise, which

integrates nicey so it effects are reduced.

op37, same thing got some of them too.

The old Comlinear op amp CLC502 was a nice fast part I did

use. think they quit making em.

[Max]

Hi Max,

The op27 is an old story, I have about 10 here from years

ago. It is low noise, problem is it doesn't recover fast

enough from saturation.

Of course all this sillyness about noise assumes there is

not a larger external or internal noise source {micro/digital}

booming away alot bigger than nice gaussian noise, which

integrates nicey so it effects are reduced.

op37, same thing got some of them too.

The old Comlinear op amp CLC502 was a nice fast part I did

use. think they quit making em.

Hi,
yes you are right... are a bit old now. I found them useful when played with PI front-ends some years ago, but of course are not recent stuff now and maybe also near out of production.

I think they still produce some of them cause there is a market for these ics still now ... cause many academic/scientific applications actually rely on that old op amps and related designs.

My point was on the parallel config that I saw many times on old datasheets of that devices to gain ultra low noise, but sure there are a lot more speedy op amps today that do the same with just one instead of many parallel op amps.

Best regards,
Max

[JC1]

I meant old subject

Hi Max,

Old discussion, you will reconize some of the participants.

Oh and btw Dave Johnson doesn't know the difference

between an uncompensated amplifier and a

current feedback amplifier {cfa}

don't let him confuse you. Here's the read.

http://www.findmall.com/read.php?34,...389#msg-130389

http://www.findmall.com/read.php?34,130384,page=2

http://www.findmall.com/read.php?34,130384,page=3

http://www.findmall.com/read.php?34,132229,page=1

http://www.findmall.com/read.php?34,...256#msg-132256

http://www.findmall.com/read.php?34,132229,page=3

[JC1]

Oh btw

Oh and the data sheets on the

OP27 and OP37 are just fine.

Don't let the spook monster

scare you.

[JC1]

lsk389

Here is another preamp article using the lsk389 fets

turns out some of them can have higher noise

as per specification. They cost $7.19 a piece.

So may want to measure them or screen them

before selecting the best.

http://www.audioxpress.com/magsdirx/.../colin2774.pdf

[JC1]

or

Or use something else.

better.