LF353N op amp replacement options for old school Genesis

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mazdapowered

mazdapowered

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Joined 2006
#1
In the process of the repair and re-cap of an old school Genesis SA30 class A amp and whilst it's apart it would be an ideal chance to upgrade the input op amp.

The current op amp is an LF353N (dual 8pin DIP), has a simple Zener/electro cap regulation and it's output is DC coupled to the amplifier which also fully DC coupled.

Any suggestions on a nice and stable replacement?

Thanks.
 
#6
If I am not mistaken, isnt the LF353 being discontinued now?

Maybe not, I cant remember. But I do remember getting hit with a digikey notice that one of those op-amps were being moved into the obsolete category. I cant remember what though.
 
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#7
Could very well be.The LF353 and TL072 are pretty much interchangeable and both about as old as dirt.From what I understand the 353 has a better GBW.But its the same old Coke vs Pepsi,Tastes great,Less filling debate.
If I were going to all the trouble of swapping them out I would make it worth while and do the OPA2134 or similar LT part.
The one thing that really bothers me is that these old TL072's and 074's are still being used in new designs.They may be fine for some things still to this day but when I crack open a $1000 JL 900/5 and see it full of them I feel they could have done a little better.
 
#8
Randy62 said:
If I were going to all the trouble of swapping them out I would make it worth while and do the OPA2134 or similar LT part.
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The OPA2134 has been dropped in and added few bypass capacitors on the opamp power supply. Using my POS scope the output looks okay with no signs problems. Can't really tell if it sounds better but along with the re-cap and extra bypass caps on the power ,it sounds pretty sweet.

Randy62 said:
The one thing that really bothers me is that these old TL072's and 074's are still being used in new designs.They may be fine for some things still to this day but when I crack open a $1000 JL 900/5 and see it full of them I feel they could have done a little better.
Click to expand...
It's pretty shocking how some decent brands are full of budget components and my biggest gripe: cheap non brand capacitors. I cracked open my Alto mobile class D on the weekend to check for any failing capacitors before it gets recycled back into the car and that had a bunch of 074's :down: There must be a better modern jelly bean op amp.
 
#9
I emailed someone who worked for Genesis. This was his reply:

LF353 was National's version of the TL072 which we also used.

OPA2134 is a good replacement / upgrade but LME49720 is the part we fit as the best upgrade.

Don't forget to change any YXB electro's as they are one of the leaky caps of that era.
 
#10
Perry Babin said:
I emailed someone who worked for Genesis. This was his reply:
LF353 was National's version of the TL072 which we also used.
OPA2134 is a good replacement / upgrade but LME49720 is the part we fit as the best upgrade.
Don't forget to change any YXB electro's as they are one of the leaky caps of that era.
Click to expand...
Thanks for doing that 🙂
Good to know the OPA2134 will be fine, if I ever take it apart again or do another I'll give the LME49720 a go.
Yep, it was a leaky cap that killed the amp in the first place. A visual inspection wan't good enough either, as the YXB cap had leaked underneath so it wasn't obvious until it was removed from the board.
 
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