IC upgrade for the LM301's and the LF356

Has anyone found a pin to pin IC upgrade for the LM301's and the LF356.  I have 6 ward beck eq's I was thinking about updating the IC's in or at least testing what some modern chips might sound like.

I was thinking of the OPA604's.  Any others that would work or might be better.

Thanks

I heard someone testing LME49710NA,OPA604 or OPA134 for lm301 replacement-

I think there is few topics for those allready
http://www.groupdiy.com/index.php?topic=35113.msg430689#msg430689
http://www.groupdiy.com/index.php?topic=4555.0
http://www.groupdiy.com/index.php?topic=14551.0

Be sure to check out the compensation circuitry around the 301's when substituting
more modern parts.

The new National parts like the 49710 are really good.

IIRC the LF356 was a decent opamp for it's time. one of the early bi-fets. Relatively fast and relatively low noise. One quirk I didn't care for was an asymmetrical slew rate limit, but that was adequately above the speed needed for most audio paths. The LM301 is indeed an old soldier, that needs to be retired and replaced with almost anything newer, maybe even a 356.

JR

Here is the schematic for the basic Ward Beck EQ. 
http://www.dandeurloo.com/diy/Ward Beck/M462_Equalizer.pdf

I think a few of these ought to drop in. 

I wonder if the National has a high enough power rating? 

Also, I wonder if you guys think I will hear the biggest difference in the eq filters or if I change them in the output amp.

Thanks for your help

Leave the LF356's in place, iirc they simply buffer the discrete output stage. Upgrade the 301's. I think when I did my WBS console I used BB OPA604's in the EQ and they sounded nice. You'll need an opamp that will run on 42v.

Mark

Use the LM49870 on a Brown Dog or similar adapter.

It's a 44v part, similar very good performance.

Be sure to pull the compensation parts connected to pin 1 and pin 8 and any
other pin for each 301 position.

You'll need to look for oscillations when you're done, the new parts are
fast and may need a bit of work to stabilize.

I would tend to put at least a .1uf from pin 4 to 7 on each IC.

You could also grab Scott L and a 12 pack and come over to the shop some night...

Dan Kennedy said:

You could also grab Scott L and a 12 pack and come over to the shop some night...

Click to expand...

Hard not to accept that offer, wish I was closer to join in.

How's the Lex 224 holding up Dan?

Mark

Dan Kennedy said:

You could also grab Scott L and a 12 pack and come over to the shop some night...

Click to expand...

Twist my arm!!!

I'm in!  I'll see Scott tonight and see what he has to say.  I'm sure will have a few demands on which brand of beer.

Hey Mark!

Didn't know it was you.

It's still running fine.

Dan

SMALL UPDATE

making some solid head way on these!  Dan Kennedy has made many excellent suggestions and we will test them this weekend.

From quick listening it has been a massive upgrade.  Much Much smoother in all bands, specially the high band and the mids.  Still a few things to check out and tweak but hopefully that will happen this weekend.

So far I used the OPA 604's.