Hey guys. I'm looking for a footswitch for my Classic 30 - would this do the trick?

http://www.gumtree.co.za/cp-musical-instruments-in-claremont/marshall-2-way-footswitch-523328068

I only need it for channel switching.

Also, I had a custom 'tube tamer' made (I have the old C30) which has worked beautifully for the tube rattle, but I've noticed that the middle 12AX7 rattles when I'm playing. It stops when I touch it with my finger and sounds like there is something inside rattling.

Can I replace this one tube, or must I replace all three 12AX7s? I'm looking to reduce that harsh 'ice-pick' sound that many Classic owners speak of.

And is there anyone in South Africa that sells tubes?

Footswitch, I'm not sure. IIRC, the C30 uses just a plain latching switch (check the manual to be sure). If the Marshall switch is latching it can work (or worst case, be made to work).

Valves, I'm not sure what shops you have your way, but you can always get from Mr Valve: http://www.mrvalve.co.za/. If you want to make sure it's the valve rattling, simply swap your 12AX7s around and see where the rattle goes.

Forgot about Mr Valve, thanks Alan!

I tried the marshal two channel foot switch, and it didn't work. You need a stereo switching foot switch. I ordered mine for R400.
+1 On Mr. Valve