So I won my first Ebay auction. I quite fancied an old valve radio. It came
today. It's a Philips "B2G25U". (Catchy name.)

No real fault of the seller's, I suppose, but it arrived with 3 of its
4 valves out of their sockets, and rattling around in the box, but unbroken.
But I had no way of knowing which one went into which socket, so had to
try and guess.

Wrong!

Two of the valves started arcing blue-violet inside and some unseen passive
component emitted some (perhaps all) of its magic smoke. Turned it all off
ASAP.

Tried another permutation. Got buzzing but no stations.

Tried another permutation. Got more promising sounding buzzing and a bit more
hopeful-sounding noise and wheezing, but no stations.

Looked the radio up on the net. Found a few pages mentioning it, but none
with much really technical info. Apparently this one is quite "unusual", in
that it does not use an output xformer, but rather a single output valve
and a 700 or 800 ohm speaker.

Except my example DOES have an output xformer! The side connected to the
speaker says "3 - 5 Ohms". I guess maybe someone needed to replace the
speaker with a more common low-Z type, and had to put in an xformer to
match impedances. (Although the speaker does look old, and kinda looks
like it could be original, so I'm a little confused.)

This radio is only a cheap thing, dating from around 1960, built mainly
on a rather naff PCB with the valve bases and most of the passive components
soldered into it.

I reckon I fried one or two of the valves when I plugged them into the
wrong sockets, but I know valves are more tolerant than transistors, but
they really didn't look happy arcing like that. Maybe a dead resistor too,
not sure yet.

I'll try and get hold of some replacement valves.

Hi-fi this is not, though. Although the websites I saw that mentioned the
lack of output xformer said that Philips did it to eliminate that component
in order to improve sound quality.

WHY did I want a cheap old early-sixties valve radio? Erm, well, listening
to Kraftwerk's "Radio Activity" album again. Got me in the mood!


That was interesting, wasn't it? Cough/


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk