[TCML] VTTC almost finished.

["Christoph Bohr" <cb@xxxxxxxxxxxxxxx>]

Hello Folks.

Its been some weeks since I asked for help with my VTTC project,
so I thought, I'd give y'all some update

Here are some low-q ( sorry ) pics with explanations.

http://www.luebke-lands.de/media/VTTC2.JPG

Now thats how it came out. The lower deck is a wooden board, the sides
are stainless steel and the upper deck is a casing that came from a 19" UPS
mounted upside down.

On Top you can see the GU81M, the by far to large anode choke, MMC
and grid leak network ( better view in some other picture below )

And on top of that, on 4 plastic spacers and a sheet of plexy are the coils,
the coupling L1/L2 is adjustable, the feedback coil is tapped every 2 turns.
The primary is tapped every 1/3 turn starting from the 15th.

The black areas are heat shrink tubing. I was working on a small budget this
time and made the primary up from pieces of scrap wire...

http://www.luebke-lands.de/media/VTTC3.JPG

This shows the front panel with switches, indicator lamps and metering.
The controls at the bottom are for the staccato, which acutally worked
on the first try, using a 30TPS16PBF. I made my own PCB for the staccato,
which is a bit smaller and uses some SMD parts, but is not entirely SMD...jet..

The switches controll filament, filament soft start ( crude sulution with resistors )
and HV. The meter is a 60mV device which mesures across a very impromptu
shunt made up from the remains of my old fan heater ;-)
Should read around 500mA full scale.
The current at full power seem to be around 400mA

The black thing on the left is the handwheel for the variac. Works like the
volume knobs on some small radios, this way I was able to lay the variac
down, easing installation. Still have to make some scale, though.

http://www.luebke-lands.de/media/VTTC1.JPG

View from above, in the center there is the staccato controller
mounted vertically on an angle bracket together with the transformer
On the right you can see the handwheel above the variac,
I think this is self explanatory.

http://www.luebke-lands.de/media/VTTC1.JPG

Side view, shows the grid leak network. the grid leak cap can be
rearrangeld in series/parallal to change values over some range.

http://www.luebke-lands.de/media/VTTC5.JPG
Impromptu ion wind motor. The inferior quality or the spinner and
the cam complement one another very well in this picture....

http://www.luebke-lands.de/media/VTTC6.JPG

And finally, some full blast... or what I decided should be full blast for now.
There were some unplesant incidents during my first experiments, so I decided not to
push it
too hard on this one to extend tube life.
However, big enough for some indoor fun in my flat. I'm still awayting the
"Bundespost"
to show up and charging me some utopian fine. TV, PC, FM Radio are all fine around
the
coil, but AM Radio ( wich is not very popular around here ) messes entirely up, still
have to find
out how far this goes... all my AM Radios are tube radios, which makes it hard to
carry
them down to street to find out ;-)

BTW, where do you ground your VTTC indoors? I conncect to the pipe of my central
heating.
The green wire ground seems to be only connected to the neutral in my house, so I
thought
it would not be a good idea to use this one...

Tanks to all who contributed!

best regards

Christoph Bohr


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