Quote:
Originally Posted by dougietamson
Quote:
Originally Posted by Edwar65
Can anyone confirm date these were made stamped 640 r6d/r6e have several that look unused in I think original boxes 
Many thanks. |
Could you upload a photo of the codes.
If the date code is R6E that's Mitcham factory May 1956, should have 17mm long anode plates too.
The I have a Mullard ECC83's with mC1 as the manufacturing revision, not seen '640' before.
Doug |
I've just checked my Mullard M8137 'box plate' special quality mil spec version of the ECC83 and looks very similar to yours.
These M8137/ECC83 are sought after by the audio eejits if test good and are matched, matched pairs especially so.
I've attached some photos of various 'long' 17mm plate mC1 & f61 plus some 'short' plate 14mm types I61 plus a M8137.
I think the change to 14mm plates came in 1959 as I have both long and short plate examples from July & August 1959.
The last ECC83 photo has Mullard UK & Holland plus a Lorenz branded Philips made in Germany and a couple of 1958 Telefunkens
Doug