Maker Pro
Maker Pro

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

E

Eeyore

Jan 1, 1970
0
Carl said:
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
0.9 nV/rtHz if it's fast enough for you.

More than fast enough.

It's only audio !

You can sort their op amp list by noise if you haven't already found that
magic button.

Ah yes. Thanks.

Graham
 
E

Eeyore

Jan 1, 1970
0
martin said:
ISTR reading that it tends to go quite unstable,( layout, gravity,
leylines, Hubble const. 440Hz, etc,)

Thanks for the warning.

but I havent checked it out on Snopes

No ! ?

Graham
 
E

Eeyore

Jan 1, 1970
0
MooseFET said:
On May 15, 4:10 pm, [email protected] wrote:
[....]
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.

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.

Snort !

Graham
 
M

martin griffith

Jan 1, 1970
0
Thanks for the warning.



No ! ?

Graham
Had a look at LME49710 from National?
1.79$ @ 1K, not in farnell yet, but probably cheaper than the 5534/2,
when it first came out


martin
 
I

Ian

Jan 1, 1970
0
MooseFET said:
And below about 100KHz. The noise rises in the 100K-1M band.
Anyone found any of this sort of opamp that _doesn't_ show this behaviour?
i.e. low offset, low noise input gain stage that gets rolled off for
stability,
2nd gain stage to get the high LF open loop gain but is very noisy so you
get
very bad output noise at HF. The AD8671 family do this.

Regards
Ian
 
E

Eeyore

Jan 1, 1970
0
martin said:
Had a look at LME49710 from National?

I did indeed find it.

1.79$ @ 1K, not in farnell yet, but probably cheaper than the 5534/2,
when it first came out

Sounds a bit like it. I have some coming as samples.

Graham
 
E

Eeyore

Jan 1, 1970
0
John said:
We pay about $5.25,

In what quantities ?

so use them sparingly. OP-27 is about $1.25.

OP-27's always been considered nice but not that quiet by modern standards. The newish National parts look very
attractive btw. They seem to be making themselves a new niche in high performance audio (with GP spinoff applications)
whereas TI seem to be losing one. I'd have thought they'd do more with the BB division.

Linear's parts (as ever) just seem to be expensive.

Graham
 
E

Eeyore

Jan 1, 1970
0
Spehro said:
$4.95 US in 100's from Digikey, 5.75 in 25's. Similar prices from LTC,
4.75 in 1K. The 'eh' version is about 50% more.

Farnell are still £6.41 / $12.80 in 100s.

They really ought to make their volume pricing more competitive.


Graham
 
M

martin griffith

Jan 1, 1970
0
Farnell are still £6.41 / $12.80 in 100s.

They really ought to make their volume pricing more competitive.


Graham
have you tried Dengove?


martin
 
S

Spehro Pefhany

Jan 1, 1970
0
In what quantities ?

$4.95 US in 100's from Digikey, 5.75 in 25's. Similar prices from LTC,
4.75 in 1K. The 'eh' version is about 50% more.

And there are are 2 manufacturers.

OP-27's always been considered nice but not that quiet by modern standards. The newish National parts look very
attractive btw. They seem to be making themselves a new niche in high performance audio (with GP spinoff applications)
whereas TI seem to be losing one. I'd have thought they'd do more with the BB division.

Linear's parts (as ever) just seem to be expensive.

Graham


Best regards,
Spehro Pefhany
 
J

John Larkin

Jan 1, 1970
0
Farnell are still £6.41 / $12.80 in 100s.

They really ought to make their volume pricing more competitive.


Graham

Many American companies, notably Microsoft, impose a European price
penalty, usually in the 20-100% range. My company doesn't. Maybe we
should reconsider...

John
 
E

Eeyore

Jan 1, 1970
0
John said:
Many American companies, notably Microsoft, impose a European price
penalty, usually in the 20-100% range. My company doesn't. Maybe we
should reconsider...

Microsoft's paractices are quite shocking.

That kind of thing just invites piracy. Many small admins here counter by running 2 copies for every 'legal' purchased one.

Graham
 
M

martin griffith

Jan 1, 1970
0
Who are they ?

Graham
They are used by a friend ( I have one ) for sourcing components for
medium production runs when the RS/Farnell prices get out of hand.Or
getting hold of wierd mil spec stuff, old style tants etc

I'll get a contact name, if you are interested, but not for small
quantities (10s or 20s)


martin
 
T

The Great Attractor

Jan 1, 1970
0
Many American companies, notably Microsoft, impose a European price
penalty, usually in the 20-100% range. My company doesn't. Maybe we
should reconsider...


Bullshit. There are plenty of sources that only charge what we pay
here. The last Co. I worked for had plants in UK, India, Germany, and
China, and The UK facility preferred UK sourced parts.
 
B

Boris Mohar

Jan 1, 1970
0
There are lots of really good op-amps suitable for or specifically designed for
low noise audio use but the most popular configuration is the dual package (for
many good reasons).

Having established that my client for the refurbished 'boutique' mic pre-amp
doesn't mind if it's non-original provided there's an improvement, does anyone
have any favourite candidates to replace the venerable NE5534 ? Bipolar or fet
input, I don't mind, the noise source impedance at the op-amp non-inverting
input is ~ 1200 ohms.

Graham

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