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Staccato coil operational- Thanks y'all




Greetings Tube coilers, and thanks to Dave and John, etc. for helping me
come up to speed with my tube coiling.

I just finished building a staccato controller for my coil per Dave
Sharpe's design, and it was working flawlessly on the first run:  "pop pop
pop pop..." The discharge makes a very satisfying sound and spark frequency
can be changed from 30 per sec to about 1 per sec.  I am using an SCR that
is rated at 600 VRRM and 25 A from Digi-Key that has the advantage of
having an isolated tab (so I can bolt it directly to a grounded enclosure
for heatsinking.)  I'm only using 9.5 Vcc for the timer circuit, although I
know that the timer works better at higher voltage.  I don't have a
regulator in the supply but I do have a 5000 microfarad electrolytic cap
and a bunch of other bypass caps that give a nearly ripple-free 9.5 volts
as far as I can tell with a pair of headphones (you make do with what you
have :>)

Finding the right phase for the staccato triggering was pretty easy.
Although the coil will generate a small spark with either phase driving the
staccato (probably due to the charged up bypass capacitor) when the power
is increased the coil won't operate at all if the phase is wrong.  I have
both my staccato and my filament transformer on the same power cord, and if
the phase is wrong I just plug the cord in the other way around.  

I still need to look at the operation on a 'scope and set the timing pot on
the 556 schmidt trigger properly.  But Dave is certainly right that this
timing control doesn't do a whole lot for the trigger.  I can turn the pot
from one end to the other and I still get nice staccato operation.   The
monostable timing pot gives from about 1 pulse per sec to 30.  I'd like to
try some potential ideas for a "super staccato" controller, including
converting the monostable timer into an astable timer, allowing the user to
adjust how many pulses in a "burst" and how many bursts per second.  Dave I
think is working on a "super staccato" controller that allows the user to
do this also but I'm not sure how he plans to effect it yet- let me know
what you figure out, Dave! 

My present 833A is an older one and so I still have the occasional problem
with a flashover.  Unfortunately the fella I just ordered a new one from
ran with my money and won't send the tube...maddening!

-Carl