LF356N OP-AMP Equivalent

[drp1003]

HI,

I'm in the early stages refreshing an old PL 400 Series II power amp - new filter caps, new diode bridge with capacitor mod, speaker protection, and control board rebuild.

There are a pair of LF356N op-amps on the control board that I want to upgrade to new. I have a pile of new op-amps laying around to choose from, from old rebuilds I've done in the past:

(2) LT1936
(2) BB OPA 2134PA
(2) JRC 2068DD

Will any of these three different op-amps work as a direct equivalent to the LF256N?

If none of those work, then give me a good one that will.

I'm not a electronics guy. I can read specs all day long and still not know which op-amp to use.

Thanks!

 

[nj pheonix]

Not my area of expertise but glancing at the data sheet it seems like it should be fine in that application.

 

[mbz]

Suggest you run your proposal past the PL guys at Pheonix
https://forums.phxaudiotape.com/

The LF356 is rather expensive, they may suggest not changing it. The are other mods that should be considered like the back to back diodes across C6(?). A speaker protection kit (Watts abundant or other) is mandatory. Also dream of the white oak upgrade...

The LF356 is a single amp, careful analysis of the datasheet is required to identify key performance parameters and confirm replacement candidates meets/exceed these parametrs. Rather time consuming so quicker to ask/search pheonix.

 

[drp1003]

Suggest you run your proposal past the PL guys at Pheonix
https://forums.phxaudiotape.com/

The LF356 is rather expensive, they may suggest not changing it. The are other mods that should be considered like the back to back diodes across C6(?). A speaker protection kit (Watts abundant or other) is mandatory. Also dream of the white oak upgrade...

The LF356 is a single amp, careful analysis of the datasheet is required to identify key performance parameters and confirm replacement candidates meets/exceed these parametrs. Rather time consuming so quicker to ask/search pheonix.

Hi,

Yeah, I did the full WOPL on my Series I amp three years ago. I have it paired with a ELEKIT tube pre. I was gonna go full WOPL with the Series II amp in question here, but decided to go down a more authentic, vintage road. I have a kit coming in from eBay (QUA-CO) that rebuilds the PL36 board; but the LF356 upgrade op-amps are left out, sold separately. It seems like you said an expensive and perhaps unnecessary upgrade. I thought I could just go ahead and do some fun op-amp rolling, comparing and contrasting the slight differences in sound. I don't think that applies in this situation. Limited to one maybe two expensive op-amp alternatives. Live and learn!

Here is a PHOTO of my work so far: New filter caps, New diode bridge with capacitor mod, WATTS ABUNDANT speaker protection kit.

 

[wyn palmer]

HI,

I'm in the early stages refreshing an old PL 400 Series II power amp - new filter caps, new diode bridge with capacitor mod, speaker protection, and control board rebuild.

There are a pair of LF356N op-amps on the control board that I want to upgrade to new. I have a pile of new op-amps laying around to choose from, from old rebuilds I've done in the past:

(2) LT1936
(2) BB OPA 2134PA
(2) JRC 2068DD

Will any of these three different op-amps work as a direct equivalent to the LF256N?

If none of those work, then give me a good one that will.

I'm not a electronics guy. I can read specs all day long and still not know which op-amp to use.

Thanks!

None of them will be a substitute for the 356. The LF356 is pretty cheap @c. $1 at Mouser. Why do you want to upgrade them?
The OPA134 will be an sonic improvement if the application is in the sound path.

 

[drp1003]

None of them will be a substitute for the 356. The LF356 is pretty cheap @c. $1 at Mouser. Why do you want to upgrade them?
The OPA134 will be an sonic improvement if the application is in the sound path.

I thought I was gonna be able to do some op-amp rolling. I have a handful of op-amps laying around left over from when I was auditioning DACs and an op-amp based phono preamp. The control board of this Phase Linear 400 has op-amp sockets. I can pull the op-amps out easily and replace them with different ones just as easily. Every op-amp I have can be swapped with the others that I have. But like you said, none of them will work on the Phase Linear.

Here are three op-amps that can be substituted for the LF356: TLE2071A, LF351N, AD825. I have no experience with any of these nor do I have them in my meager pile of leftover op-amps, so I'm not gonna bother with upgrading right now. Perhaps in the future.