[sdiy] Silver series TL074/84 op amps

Tim Stinchcombe tim102 at timstinchcombe.co.uk
Sat Mar 19 20:27:56 CET 2016


Hi list,
	I'm hoping someone here can shed some light on what the 'special
purpose' of the silver-painted TI op amps were, which I've seen on several
occasions. The chips are clearly painted with silver paint and re-marked,
which in today's times of blacktopped counterfeit ICs looks very suspicious,
but back then (and I'm not sure when 'then' was either!) must have been seen
as acceptable. I'm presuming this was some sort of post-encapsulation
sorting for some parameter or other, thus giving a 'premium' chip?

(I'm certain this was either mentioned here a few years back, or I've had a
conversation with someone about it at a Synth DIY meet or somewhere, but
I've searched the archives and came up blank, and Googling turns up very
little, apart from one brief mention in a Gearslutz thread.)

There is a photo posted on the 'dodgy chips' thread at MuffWiggler:

https://www.muffwiggler.com/forum/viewtopic.php?p=2179517#2179517

for anyone not sure what I'm talking about (and in fact it is a PM in
relation to that which is causing me to ask!)

Cheers,
	Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at timstinchcombe.co.uk
www.timstinchcombe.co.uk




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