[Amps] GS-35b fully-submersed oil cooling

[Steve Wright]

On 21/03/15 05:00,

"Jim Thomson"<jim.thom at telus.net>wrote:

>   properly designed system would have a sump where the water would
> naturally separate from the oil, and a valve to drain the small
> amounts of water collected over time.

No.  A properly designed system won't have a single pin-drop of moisture 
in it to begin with, and if it did, a refrigerant drier would remove it.


> ### The problem with oil immersion...which is used on some eimac tubes per the
> Eimac catalog is..... if you install a metal tub surrounding the tube... you now have
> stray C from the enclosure to the the anode....which can affect the PI net on the
> upper bands.   RF parts used to sell a metal chimney..with a teflon ring on top, for
> the 3CX-3000A7 tube..for air cooling.  It added 10 pf of C.
> Tube is 24 pf from anode to grid, measured on a wooden bench.
> And when inserted in the socket, rose to 33 pf.
> That extra 9 pf is caused by the proximity of the lower anode fins to the chassis below.
> Once the metal chimney was installed, it rose to 43 pf.

Thank you for that.  I had a quick google, but did someone want to offer 
an opinion (or better) that such a metal chimney or (container/tub) 
might make a 6m amplifier infeasible?

The increased dielectric constant of the oil will also act to increase 
that capacitance.

If the Eimac thought it was appropriate to use a metal ring in close 
proximity, then likely it was usable for I to do it as well.

It also seems, there may be the opportunity to entirely and safely 
encapsulate the HT

>
> ##  any oil cooling scheme would involve the use of an external oil pump +  external air
> cooled radiator. ANY leaks anywhere, and you end up with a real mess on your hands

Of course.  But there are quality crimp fittings available everywhere.  
I'd also have a drip tray under the tube sockets.  In the end, it's a 
nice clean-smelling quality oil.  It isn't dog shit.


Steve