Quote:
Originally Posted by barrymagrec
In the original Williamson amplifier book there was a version for PX4s as well as the more familiar KT66 version.
They were to all intents and purposes identical. I changed my PX4 version to the KT66 type after an unfortunate accident involving a leaky garage roof and the mains transformer, the replacement had no 4 volt windings.
|
What do you mean by "the original Williamson amplifier book"? DTN Williamson wrote several articles for "Wireless World" which were later gathered together as a pamphlet entitled "The Williamson amplifier" but nowhere in it is there a design for his amplifier using PX4s. He does mention the PX25 but dismisses it in favour of the KT66. There was a design for a push-pull PX4 amplifier in a "Wireless World" article in 1943 but that wasn't by Williamson.
There were quite a few variations on the PX4 by other British valve manufacturers but I doubt if they are any more available or cheaper than the original.