Ah, Actually, it was 20 - 30 RF volts. Grid drive is around 5 MA. I use mine with a Pacemaker driver, and a 20 DB ~ pad inline and the connecting coax is prescribed to be 60 inches long to prevent parasitics.
The thunderbolt can also be driven directly by an (un)modified Central Electronics 20A, or the CE 10B, I use both of them from time to time. In SSB mode, you really need to watch the audio levels and monitor the RF output waveform, however I found that when running AM from the CE rigs you really have to be careful not to bang the audio as well as the T-Bolt goes right along and you end up with a higher carrier level and lower read (muddled) audio. The 1962 ARRL handbook has a single 4-400A amplifier, which I think is the original question, I built one in the 1980s I had no problems with it, and I redesigned the output to use vacuum variables and a roller inductor instead of all the thrashing around with jumpers. It worked quite well, and I still had to reduced the drive level to keep it in limits for the tube. With 3KV on the plate it is quite handy for rtty and cw, the AM was handled by lifting the modulator circuit from a t-368 schematic, worked quite well. Jim WB2FCN Patrick Jankowiak wrote: > > The Thunderbolt was easily driven to full input by 20 watts. I > recall it was easy to tune and very sensitive due to grid drive. > The grid was swamped as I recall, so it was also very stable. > > PJ > -- > > the Johnson Thunderbolt is a AB2 amp that uses 4-400A's check > out this amp > i think you might like the layout it uses a roller inductor > instead of a > varicap. > 73 Tony wa4jqs > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected]
