Salvaged from a "grand-daddy" valve oscilloscope - a Taylor Model 31A
Taylor Electrical Instruments were a designer & manufacturer of test equipment in England
The company was purchased by AVO in 1958 and eventually AVO (which was purchased by Metal Industries in 1959) was purchased by Thorn Industries. A lot of structural changes were occurring in the electronics industry at this time.
The equipment dates from the early 1950's! see the photograph to view this ugly beast in all its former glory.
After evaluation, I decided that full restoration of this Taylor scope was not a viable project so this is one of the parts I have removed.
Brimar Valve
Made in England
Age is estimated as during the period 1953 to 1970. The equipment was manufactured in 1953 but based on the type code (see below) I believe this valve was made in 1966.
Type: 12AT7 (ECC81)
Classic input stage dual triode
Black folded box plates
Checked to ensure this was made by Brimar, all indications are that it is NOT from another factory and badged Brimar.
Type code markings are:
128 (just below the type number - possibly a batch number)
3A5/565 (on the glass envelope near the base, 180° from the type number markings)
The world of type codes is tricky, have a look for yourself at:
http://www.audiotubes.com/mullcode.htm
As this is a 3 + 3 format, introduced after 1956, I believe the bottom row 2nd character indicates this was made in 1966
Visually the valve appears in great shape, no rub-off of the print.
Unfortunately I am now "dead in the water" regarding tube testing - my testers have all been sold (doh!) and I don't have a valve amp here to test by substitution.
The equipment it came from WAS working way back in the 1970's (!!!) but then it has sat in storage for years and now the electro's all dried up so I cannot fire up the gear any more - in fact I have parted it out.
So I am "quite" positive that the valve has good emission and is not noisy but I cannot check this for sure.
Make any purchase with the fact in mind that this tube is UNTESTED
