HISTORY:
I found these nice shields inside the TAYLOR Model 31A oscilloscope (British made 1953)
The scope was in need of such extensive restoration that I decided it was a "parts job" and off she went to the operating table. The caps and very old carbon resistors were completely shot but there remained some interesting and perhaps useful parts - these shields are one of those "useful" items.
This valve shield is for use with 7 pin tubes e.g EF91 etc (see the dimensions below)
Mu Metal valve shields were once commonly used with test equipment many moons ago, the idea is that the Mu Metal has special properties which help reduce external magnetic interference to the very low level signals inside the tube. For more technical information about the wonderous Mu Metal, take a look HERE
Mu metal products work, I have used them many a time in front end audio amp design but these days most people don't bother as cost is a major consideration (it's expensive stuff these days!)
UNBRANDED - Valve Top Shield
Circa 1950's
Most likely made in Britain
Colour: Gun metal Grey (raw/unpainted)
Part # Unknown
Designed for use with 7 pin valves
Shield has no identification markings at all
SPECIAL FEATURE: Mu Metal construction
It used to be common to find valve shields made of Mu Metal (Nickel/Soft Iron with a little bit of Copper and Chromium Alloy NON FERROUS) but these days Mu Metal in any form is VERY expensive. The Chromium gives that Gun Metal Grey case a slight Green/Yellowish look.
Fixed inside the can is a metal spring, this ensures the valve is snug and secure inside!
Note the design of the locking section at the base (attempted to show this in the photograph), you will need to ensure that your valve sockets can fit this type of shield
DIMENSIONS:
50.25mm height x 21mm diameter (top) x 5.75mm thick Mu Metal walls
WEIGHT: 12g
Noticeably heavier than an equivalent Aluminium based shield
COSMETIC CONDITION:
USED
CLEAN
NO physical deformation (that would be difficult, this metal is as tough as nails!)
Base locking system is undamaged
*** Where the photograph shows multiple components, this advertisement is for ONE component not all that are shown!
