Very low noise SINGLE audio op-amp in DIL-8 ?

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It's retrofit into an existing socket.

The 5534's en is ~ 3.5 nV/sqrt Hz btw.

Graham

Why not just use half of a dual you know and love?

Best regards, Spehro Pefhany

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OP-27?

John

Eeyore a écrit :

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Why not just keeping it? At 0.4pA/rtHz, the 5534's current noise will be unnoticable. And since 1200R is 4.5nV/rtHz, total noise will be 5.7 (for a 2dB NF). Getting down to a total 5nV/rtHz will require a less than 2nV/rtHz opamp, which you'll probably don't like (cost).

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non-inverting

A blast from the past ! I must look at it again and there's the op-37 too IIRC.

The best I've found so far is National's LME49710 (I didn't realise they did a single part) which boasts typical mid-band en of 2.5 nV/sqrt Hz and stupendous linearity and wonderful DC figures too. I expect In will be better as well.

Graham

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linearity and

Ok, I have some samples on order, Farnell doesn't stock them yet. This part actually smacks of a deliberate intention to make a form-fit-function equivalent upgrade for 5534s ( and 5532s with the LME49720).

AD have better of course but it's a dual in SOIC. It's tempting to make a converter board and 'throw away' the unused half !

Graham

LT1028 is around 1nV/rtHz above 100Hz.

a single

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upgrade for 5534s

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What about AD797 or AD829?

Or LT1028

a single

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Isn't the AD797 supposed to be the "ultimate" audio opamp from AD?

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LT1028 is a fabulous amp *if* your signal is very low impedance. We use them as current-shunt amps with ppm precision. The feedback resistor current is so high that we put another, cheap opamp in the loop just to drive the feedback, so we don't heat up the 1028 and spoil its beautiful offsets.

Current noise is high.

Maxim did a MAX1028 for a while, but I think LTC stopped them somehow.

John

did a single

linearity and

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upgrade for 5534s

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Probably by ordering some, which always causes Maxim to discontinue parts...

Cheers,

Phil Hobbs

a single

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ISTR reading that it tends to go quite unstable,( layout, gravity, leylines, Hubble const. 440Hz, etc,) but I havent checked it out on Snopes

martin

did a single

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upgrade for 5534s

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I've never used that AD797, but I suggested it once as a possible alternative to the LT1028, and the guys that tried it were very happy. The output stage of the LT1028 can be a bit cranky with some loads, and the AD797 is apparently rather nicer.

It is a relatively fast op amp, good for 20V/usec output slew rate and the data sheet does emphasise the need for good decoupling and careful layout, so there are people around who could find it unstable.

-- Bill Sloman, Nijmegen

I've used the Analog Devices AD829 as the second stage in a preamp and it worked well. Specced at 1.7 nV/rtHz. They also have the AD797 at

-- Regards, Carl Ijames carl dott ijames aat verizon dott net (remove nospm or make the obvious changes before replying)

If you can live with +/-5 V try MAX412

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LT1027 is very like an op-27

On May 15, 4:10 pm, snipped-for-privacy@ieee.org wrote: [....]

The LT1028 can be tricky near unity gain. They really hate being smacked into the rails and don't like hitting slew rate limit. Other than these things they are actually not too bad to work with.

Since this is high end audio, you may want to look at parts like the LT6230-10. These give better highs.

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And below about 100KHz. The noise rises in the 100K-1M band.

Thanks, Phil, you made my day.

robert