Switching opamps, where can i get them

[Ice-9]

I'm looking for some switching opamps for a little amp project i'm starting. What i am trying to source is a dual op amp that has a control input that switches 1 opamp on while the other is off, I want to use these for channel switching and gain boost switching. I know Marshall have used this type of opamp in some of there gear and the chip number is M5201. I haven't been able to find these available but does anyone know of another more available type. Thanks

[brett]

Hmm..
a DIP-8 package doesn't have any spare legs, so I don't know where the control would go...
If you are ok with 2 x single op-amps, you can make/break the earth or power supply using a mosfet (BS170/2n7000) as a switch.
cheers

[oddist]

Hi,
Try Maxim.  May not be the exact ones used in Marshall, but they have (or at least used to have) a variety of such op amps.
Good luck!

[edvard]

Here (if you're in the UK):
http://www.tubeampdoctor.com/product_info.php?products_id=1769

Also known as JRC or NJM2120D, with the 2121D as a higher-slew-rate compatible upgrade.
Mouser has them for less than a dollar...
http://www.mouser.com/ProductDetail/NJR/NJM2120D/?qs=sGAEpiMZZMsBYeZNO4kNBF83MazEF%2f7O
http://www.mouser.com/ProductDetail/NJR/NJM2121D/?qs=sGAEpiMZZMtCHixnSjNA6PRGqGBqB8eMI2KOllXwyxw%3d

Interesting concept, I'll have to look more into this...

[PRR]

> I don't know where the control would go...

It is really a single op-amp with two input systems and one output system. So there are four input pins and one output pin, leaving one pin for control.

[Ice-9]

Here (if you're in the UK):
http://www.tubeampdoctor.com/product_info.php?products_id=1769

Also known as JRC or NJM2120D, with the 2121D as a higher-slew-rate compatible upgrade.
Mouser has them for less than a dollar...
http://www.mouser.com/ProductDetail/NJR/NJM2120D/?qs=sGAEpiMZZMsBYeZNO4kNBF83MazEF%2f7O
http://www.mouser.com/ProductDetail/NJR/NJM2121D/?qs=sGAEpiMZZMtCHixnSjNA6PRGqGBqB8eMI2KOllXwyxw%3d

Interesting concept, I'll have to look more into this...

Thanks Edvard i am in the UK. Wow i just checked out that link to the tubeampdoctor. i think i will have to look at other options as 8 euro for one is rather expensive. The mouser link looks interesting, i didnt realise they were in england.

[edvard]

i agree 8 euro is a bit over the top, but for the purist who wants only original parts, that's the way to go. 

That said, everything I found indicates that the M5201 really is just a re-branded JRC2120D, so you'd be safe going with that or the NJM2121D upgrade.
In fact, I'd just go with the 2121D because it's got a better slew rate (double the M5201) and it's going to be more available in the future.

I'm not sure if Mouser's subsidiary there in the UK is just a branch office, or a full supply point.
Somebody a few weeks ago expressed satisfaction with the turnaround time on their Mouser order from Germany, so you'll probably get pretty good service.
The other big supply companies Digi-Key and Allied didn't have them, and neither did Tayda or Futurlec so Mouser's probably your best bet unless you know a good supply shop in your neighborhood.