Help: replacement opamp?

[Jason D]

I am trying to fix an old Crown power amp. I want to replace the opamp. Its a UA739, a 14 pin dual low-noise opamp. Anything similar, or newer and better?

[RDV]

Anything with this pinout should work. I'd suggest Burr/Brown if possible.


RDV

[RDV]

Here's what Ti has in that package.
Results

RDV

[Anonymous]

Jason;

I'm not sure - but it's possible that the UA739 is the same chip as the Obsolete LM4739.

It's a dual-op amp in a 14-pin DIP package that's been discontinued for quite some time.

The Good News is it isn't hard to work around it with a better 5532 chip (8-pin DIP)

Here are two links that can help.

http://www.paia.com/parts.htm    
4739 adapter kit
- and -
www.geofex.com

has a page called "Substitutions for Anderton EPFM Parts"

JDW

[Jason D]

Thanks!

One thing that may be a problem with using any of those is that the Crown D60 uses the both sets of input/output lag pins on the opamp, according to the schematic.

I have never used these on an opamp. Don't know really what are.

Any idea?

[bigjonny]

First guess is that they allow you to adjust the input/output DC bias so that when no signal is being passe the Voltage is 0.

[Mark Hammer]

The ua739 is not the same as the 4739 that Anderton made famous.  It IS a dual op-amp with the identical pinout but the ua version is not internally compensated and needs a cap in the compensation loop (i.e., those pins labelled "nc" in the diagram shown are *busy*).  I learned this the hard way because I bought a bunch years ago and never used them because I couldn't figure out what cap value would make them work properly in the EPFM projects.  Send me a note offline and I can spot you a few.

[Jason D]

Mark, by "not offline", did you mean email?[/quote]