Help with first VTTC

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

Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

Hi everyone,

Im about to build my first VTTC, and i dont know very much about vacuum 
tubes, or their circuits.  I do have a coil that i'm modeling mine after, 
and i have some questions about the operation, and schematic.  here is the 
coil i intend to copy, I already bought all of the parts so im sticking with 
it.  Please read my questions, then look at this(or vice versa), i really 
need some help!

http://www.angelfire-dot-com/electronic/cwillis/811acoil.html

Here goes with the questions
1.  Do i need to ballast(current limit) my MOT??

2.  Why does the filiment transformer tie into the HV part of the coil?? Im 
using a seperate filiment transformer, so do i need to do this?

3.  The explenation says that the MOT does not have a level shifted output, 
then why does it have both a cap and diode on the output?

4.  Can the value of C2 be changed from .02uf to another value, i have these 
selections:.01 , .015 , .03         Will any of these work, particularly the 
.01 or .03.  What else will change due to this?

5.  Would this coil work better with a different pri/sec set up.  I am 
making the one he has on the page, but i also have available a 3.5"x12" #28 
wound secondary, and some 6"PVC available for the primary coil.  If i did 
this, what would be a good number of turns for each coil on the primary 
side??

6.  Do i need a variac?  The page doesnt mention one, if i do need one i 
dont have one(hmmm).

7.  Why on earth did he put a switch off of the output of the MOT?  Its at 
2000v 500ma, sounds really risky, but i guess thats so the filiment can heat 
up with out the plate supply on.  I van avoid this with the seperate 
transformer.

8.  How could i modify this circuit later on, to run 2 811A tubes(i have 2 
of them, matched pair).

I totally appreciate any help since im in the dark, and need to learn 
something about tubes, and tube coils. Im particularly needing an answer to 
#4. Thanks to all,

Steve Ward.

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