Re: red 304TL

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 11/15/02 11:14:49 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:


>. I used a flat spiral primary, which
>the tube coil experts tell me is a bad thing. I used the same basic circuit
>with different component values for my 811A coil, which uses the
>conventional helical primary design, and it works fine, so the primary is
>probably the biggest problem with the 304TL coil.


Sue,

I used a flat primary for my 36" spark tube coil and got good results.
However when I tried a flat primary on a smaller coil it worked
poorly.  I suspect the problem on the smaller coil was that I
installed the grid coil around the outside of the primary instead
of at the center.  The coil may have had other problems too.
That was the VT-27... a coil that was possessed by demons.
After doing an exorcism, I installed the flat primary into my
TT-42 TC where it remains today, and works well, demon-free.

If a flat primary is used, be sure it has enough turns.  Primaries
with too few turns have probably ruined more tube coil projects
than anything else, especially at higher voltages.  (It's really
the inductance which you want to be high to give a suitable
load impedance to the tube.)

John

(just kidding about the demon thing    :)