[sdiy] Tellabs Q81 or is it Ultronix Q81 or maybe Vishay Q81, no, Vishay U81.

[Tom Arnold]

So, I kinda accidently ran across some info so I figured I'd share.

What ever happened to Tellabs?  They got bought by Ultronix.
And Ultronix?  Bought by Vishay.
And the Q81?  Was made until 2 years ago under the same part number,
available by special order.  Yes, supposedly up until 2002 you could order
the same clunky ugly huge resistor you see in all manner of old Synths, you
just had to know which Vishay office to call.

What about now?  Available as part U81, also special order.  Difference is
its only 1/8th watt and has a max temp of 140C.

For an example of the resistor, hit vishay.com and look up the 185A.  The
U81 is wound on the same core.
http://www.vishay.com/product?docid=69101&query=185A
Its wound with 3500ppm wire however for additional cost they can wind it
with 3500 and 10ppm wire to make it whatever you'd like within 1 few ppm, of
course realising this stuff has a wide tolerance.

Minimum order is around $150, dont know how many that'd get.  probably not
many.  If you want to try and buy some, dig on Vishay's website until you
find the Vishay Ultronix sales office.  I cannot remember the engineers
name as he woke me up at 6:30 in the morning and my brain is only partially
functional right now.

The engineer that returned my call mentioned that they use Kovar wire if
that info interests anyone ( maybe wind your own tempcos? )

Didnt someone ( Paul S? ) mention that the actual magic tempco number was
actually +3350ppm?

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 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
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