For Sale: 19 Set Spare Valve Box

[Chris Suslowicz]

Originally Posted by Bob Carriere

Hi David

If this means that it is a for a USA mark II set what would be in there for the Canadian mark III as a substitute for the 1148 ......??? and can the 1148 be used in the Canadian mark III...??

Curious as I have some..... in fact I think all my spare boxes have 1148.

Cheers

British sets used the CV6, VR135 (DET20), US and Canadian sets used the slightly different E1148 which had a lower mutual conductance (gm) figure. R33 (27,000 ohms) was shunted with R33.1A (47,000 ohms) to allow this to work. (If the British valve is used instead, R33.1A should be disconnected.)

I thought the fabric 'socks' were included to protect the operator's fingers if changing a hot (or broken) valve.

The valve carriers I've seen in US and Canadian cases were all stamped metal with sockets fitted. British cases had sponge rubber inserts - a block that virtually filled the case and had holes to take the valves, or a grid of rubberised animal hair partitions. Later cases with /T (tropicalised) suffix had an arrangement of plastic-impregnated cardboard tubes (bonded together) and the valves were supposed to be inserted still in their waxed-paper wrapping (to provide some vibration damping).

The case designs varied slightly between manufacturers, different catches, etc. but were all interchangeable. (The carrier insert would differ according to intended application - WS19 and 22 used the same insert with a different content list in the lid, WS19HP had Case No.5 with a wooden framework that held 4 x 807s, and a drilled wooden block near the lid holding spare lamps and fuses (for the British "Amplifier RF No.2", not the Canadian one).

Best regards,
Chris.