Tram D201. This valve set features both a channel switch and a receive-only VFO. The set can be modified to transmit in the VFO position (but I can't remember how right now). The set has 2 6L6GC power valves: one for the transmitter final, and one for the audio. The final wears out faster, so when it comes time for replacement, you can swap it over with audio valve. If that gives less power, then you know someone has pulled this trick already and it's time to buy some new valves. Remember to retune the output stage once the new valves are installed. Be very careful of the lethal voltages that exist around valves - it can kill you.