[sdiy] Silver series TL074/84 op amps - belated thanks

[Tim Stinchcombe]

A belated thanks to all those that responded - some interesting theories!

I finally remembered to ask at the TI forum, hoping that someone from TI
might show up with a definitive answer, but sadly that didn't happen:

http://e2e.ti.com/support/amplifiers/etc_amplifiers__other_linear/f/18/p/505
084/1849554#1849554

As a few suggested, I think the only way we are going to find out is by
trawling old databooks/datasheets in the hope of finding one which actually
mentions what this 'package' means - other than that we are mostly left with
guesswork...

Tim
__________________________________________________________
Tim Stinchcombe 

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



> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at dropmix.xs4all.nl] 
> On Behalf Of Tim Stinchcombe
> Sent: 19 March 2016 19:28
> To: 'synthdiy diy'
> Subject: [sdiy] Silver series TL074/84 op amps
> 
> 
> 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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