Original JRC 4558 opamp in 80's PA head >??)

[analog kid]

I found some JRC4558's in my 1980's ROSS PA Head that I was disassembling just a couple of channels out of to scavange a few caps and jacks. They are "DD" not "D" . BUT I thought it worth a look since this thing is made from around the same time the original TS was still in production. Firstly would these OPamps be ANY different than the same model #'s you can buy right now through MOUSER,etc.. And if they're not and there is some OLD STOCK mojo to them as far as using them for overdrive o.amps.....Is there any difference (or major difference) between the single D affixed and the "DD" ?? I thought it may just be a operating temperature type thing as it seems to often be with o.amps.
Anyway. There are two amps in each channel of the head (a JRC 4558DD/01553 AND a JRC 5532D , which I'd like to know what type it is too. may be useful as well) And since the head is pretty much of no use to me and has just been sitting a long time. I thought if these chips WOULD have any advantage over current production 4558's , then I wouldn''t mind desoldering a few out to try in my Opamp based overdrives!
 BTW I haven't tried the NOS JRC/ TI chips or even heard an ORIGINAL tubescreamer however I cannot imagine that Any chip could be clearer , more toneful , or more transparent than that BURR BROWN 0PA2134 !!! That thing smokes all the 4558's that I have on hand!!
And also Sorry if this is a real BONEHEAD POST!!! :wink:

[Khas Evets]

DD's are low noise versions of the D. They were used in SD-1's.

[MartyMart]

It's by no means a "bonehead" post, the "which opamp" debate will go on
and on and on ..... one persons "great tone" is another's "shit tone"  !!
And .... as always, it will depend on you/your ears/your gtr/your amp !!

I didn't realize that the "DD" s where low noise ? that's interesting as I
removed some from a "Park" SS amp and improved it no end with a bunch
of Panasonic NE5532's  !! - which BTW would tell me you have some from
that amp also - just the "JRC" version.
They should all be useful - just "suck it 'n see"  

Marty.

[markr04]

I can't find the DD version around me, just the D. For what it's worth, I read that the DD meant "double shielded".

[Joe Hart]

Does anyone know what "DX" after the 4558 means? I scavanged a JRC 4558DX chip. Thanks.
-Joe Hart