February 2017: I’m often asked if I ever have any SSB adapters. Last December (2016) I picked up a couple of adapters from a friend with a view to getting them working an then selling them on, on his behalf. This gave me the perfect opportunity to look at them in detail and understand them better. The first one was an RA63B, the other was a customised RA98.
As the photograph above shows, the RA63 was not in a pretty state. Two of the knobs were missing, as was the Perspex window behind the Fine Tune knob.
The story wasn’t much better on the inside. Three of the valves were missing (2 x 6AS6 and 1 x 6AU6). One of the valve bases cans was missing and another was the wrong height (too tall). I fitted the missing valves and powered the adapter up, carefully. No smoke … so I then connected it to my MK1 RA17. It worked … but there was a lot of noise and crackles. The audio stage, V5, 6AU6 was running VERY hot and the HT was very close to 300V … a bit high for my liking.
A peculiarity of the RA63 is that although all the valves are B7G, the screening
cans are all B9A. This might be a way of minimising the build-
I had used my only spare 6AU6 replacing the missinge one so I ordered a couple of spares and a couple of 6X4 recifiers valves for good measure.
Whilst waiting for the new valves to arrive, I set about refurbishing the adapter.