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Re: Building A VTTC

Original poster: Mddeming@xxxxxxx
Hi Dr. H,

The staccato contrrollerr must be more than just a pulse-width controller. PWCs cannot lower the frequency at which the pulses occur, only their width., ie you can't get 20 PPS from a 60 Hz source with just a pulse-width controller. While any tube can be operated far below its design parameters for longevity, some tubes are designed so that, when operating properly, they are in the "glowing plate mode" without melting. When in doubt R.T.F.M. (RCA TT-5) ;^)

73s / 88s ???
Matt D.

In a message dated 8/23/06 9:01:20 A.M. Eastern Daylight Time, tesla@xxxxxxxxxx writes:
Original poster: "Henry Hurrass" <Dr.Hankenstein@xxxxxxxxxxxxx>

I think the whole idea of the staccato controller in the first place is to
limit the "watts dissipation" that the plate really thinks it's seeing. As
an example, if you limit the duty cycle to say 50%, you could conceivably
double the plate dissipation (thus producing a longer spark), but the
"average plate dissipation" would still be below the "max plate
dissipation" allowed for the tube. I.E.: 500W times 50% duty cycle equals
250W avg. = longer spark. Without the staccato controller (which is really
only a pulse width or duty cycle controller AKA: CW Mode) the plate would
normally melt. I personally do not like to see plates glowing any color
other than black for longevity of the tube. Who cares what the BBS rate is
as long as you find the sweet spot where you would back-off the duty cycle
to make your coil a long time AND a long spark performer. Look at the
plate: If it's glowing, you are probably giving too much "hammer".  enjoy
and BTW nice work!

Dr. Hankenstein