Source for AD op amps?

hifikrazy

Wammer
Wammer
Jul 27, 2005
1,083
6
0
, ,
AKA
Tim
Tried RS and Farnell? Could always get AD to send you some samples
wink.png


 

Uncle Bob

Wammer
Wammer
Sep 23, 2005
246
1
0
, , United Kingdom
I thought that might be the case - I've been thinking about building one to go with my recently acquired Grado SR225's and the question of which opamp to use has been occupying my 'daydream' time for a little while now.

Actually, RS are showing these as "Extended range items" so they're not available from stock and may be subject to extra shipping/handling charges.

Farnell don't stock them in the UK but you canorder from their US sister company Newark via Farnell for an extra 12.95 s&h on a 3 day delivery.

Digikey will also ship to the UK but I haven't checked if they stock the AD843

Which amp design are you building?

 

Ant

Wammer
Wammer
Aug 5, 2005
3,909
2
68
Hythe, Kent
AKA
Antony
I'm thinking about using burr browns instead now.

I just came up with a very simple design myself starting with the straightforward chip and two resistors. Adding a bias current to take it into class A then running into a buffer due to the low impedance of the grado phones.

I'll draw a schematic once it's built as there will definitely be some changes.

Once I'm happy I'll be trying to get it all done with surface mounts to try and keep the signal path short.

The designs I've seen on the web (cmoy variants) look fairly straightforward.

 

Uncle Bob

Wammer
Wammer
Sep 23, 2005
246
1
0
, , United Kingdom
I've been thinking about building a PIMETA - the design isvery similar towhat you describe - i.e classA bias with opamps driving buffered outputs. You'veprobably seen it already but the details are here

http://tangentsoft.net/audio/pimeta/

lots of good info on that site, the schematics and pcb artwork are available if you have facilities for making your own boards or they're available for $7.50 each.

The (pimeta) parts are mostly available here (farnell and RS) except for the class-A bias transistors but they're only $1.50 for a set.

 

Ant

Wammer
Wammer
Aug 5, 2005
3,909
2
68
Hythe, Kent
AKA
Antony
I'd not seen that, I like the idea for the buffer, although I'll still do it my way I think
smile.png


Actually for the Bias circuit can't you just use any jfet's in there? there must be something available.

 

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