Replacement for NPD5565?

[SQLGuy]

Hi folks,

My PS Audio amp uses NPD5565's for its input section. These are obsolete, but Linear Systems lists their LS844 as a sub. I am not sure if this is correct.

The noise, drift, and matching on the LS844 are certainly better than the NPD5565, but the gain seems much lower. Please let me know if I'm reading the data sheets correctly.

LS844 - Yfs typically 1.5mmho
NPD5565 - Gfs typically 10mmho

Are Yfs and Gfs the same thing? If so, wouldn't there be better subs than the LS844... like maybe the LS5911?

Thanks,
Paul

 

[mtlin12]

You can try Vishay siliconix 2N5565/5566, the package is hermetically-sealed
TO-71 different from NPD5565's mini-DIP, but I think it still can be pin compatible.

 

[SQLGuy]

I looked at that, but it's a bit pricey... Mouser's the only supplier where I've found them and they want $83 a piece! (no typo on my part... don't know if there's one on Mouser's end).

The funny thing is, if you put in 2N5565 into Linear Systems' cross reference app, they cross it to LS5911. 2N5565 and NPD5565 are the same devices but one is TO-71 and the other is DIP8. Both LS844 and LS5911 are available in both TO-71 and in DIP8.

I had already ordered some LS844's based on Linears' cross ref guide, but I think I'll call them tomorrow to find out what's up here.

Thanks,
Paul

 

[PH104]

Paul --

How many of the 5565's do you need? I might have a Siliconix or two kicking around if the LS don't work out. I'll check tomorrow.

Phil

 

[SQLGuy]

Well, I checked with Linear Systems, and their initial reaction was that the LS844 was not the best choice to replace an NPD5565. Apparently their cross reference guide has not been updated in a while. With such a difference in gain, I kind of wonder why they ever recommended them, though.

Their recommedation over the phone was their newer LSK389 device. I guess I'll shelve the LS844's until I come up with a project that could use them.

Phil: thanks for the offer. I'm going to try first swapping the existing 5565's to see whether the noise follows the right channel device. I'll let you know.

Cheers,
Paul