RE: Re: tank circuit of VTTC

["Herwig Roscher" <herwig.roscher-at-gmx.de> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

David Trimmell wrote to the list:

> but the 833C is around 400 Watt.

David,

So, it's an improved version.

> I use a small muffin fan pointed at the tubes and primary for 
cooling on extended runs
- I'm using a 28 W fan trying to blow air through the valve socket in 
order to keep the temperature of the base seal low. As the holes in 
this socket are relatively small, the cooling isn't very effective.  

> I have run the 833's up to 5500V without internal arcover. 
- You are daring. ;-)
 
> > 4. Is there any rf bypass for C1?
> Not sure of what you mean? All grounds are a common RF ground, so the
> filter cap should bypass most RF to ground.
- Some VTTC coilers use additional bypass caps as these filter 
caps don't offer a low impedance for rf.

> > 6. In the schematic your tank coil is not tapped. How did you 
> > manage the tuning?
> Let me apologise, my schematic still needs some work, values are from
> memory, not notes. I designed the MMC to give me a "close" value, and can
> tap up or down the string, not perfect, by far.
- No problem! I'm intending on achieving the tuning in the same way.

> Here you are in new territory, I have not gone over the 5KV mark much.
- Of course I could use lower plate voltages as well, but I've got the 
components for a 10 kV PSU already and the tube cries for HV and 
high power  :-))

> Just watch the temp and perhaps forced air (from bellow) would 
be good.
- I'm planning on air cooling the MMC (first) and the secondary as 
well.

Regards,

Herwig