Valve Announcements and Adverts

These are some adverts from 1950's issues of Wireless World (called Electronics World now). I hope I'm not breaking any copyright - they are adverts after all.

KT88

First of all, for all the KT88 fans, here is the original announcement of the KT88. Notice that the anode dissipation is 35 watts not the 42 watts of later models. The envelope appears not to have the distinctive 'bottom shoulder', nor does the base have the metal ring. Can anyone tell me if this is artistic licence or whether the first ones were really like this? Mail me at andy.cowley@uwe.ac.uk

12AX7/ECC83, 12AU7/ECC82, 12AT7/ECC81

I had a discussion with Ned Carlson about whether the ECC83/12AX7 was a U.S. or U.K. invention. I had always assumed that it was a Mullard design - Mullard ones were always regarded as the 'real McCoy' here in the U.K. Ned was right of course! - here's the proof that even in the U.K. the 12AX7 was the first.

This is a Brimar advert from February 1950.

These are probably inported from the states and relabelled by Brimar. Any ideas who really made them?

This is the Mullard announcement from October 1953.

Mullard did have the ECC81 about 9 months earlier.