[Amps] Tubes vs. Solid State (was) Expert Amps2K-FA:AnyOpinions?

[Paul Christensen]

> I know that it doesn't take much water volume to cool a tube running the
> legal limit.  A 1/2" tube with just a gentle flow is more than
> sufficient for 12 KW out CCS.

Very little water flow is needed from a cool source.  Back in the '80s, I 
managed an FM site atop what is now the Wells Fargo Building in downtown 
Jacksonville.  An Altronic Omegaline water-cooled load was used for testing 
purposes.  These cylindrical devices are only about a foot long and perhaps 
4-5 inches in diameter.  Contained within the metal shell is a single glass 
resistor.

The water source?  Simply a garden hose connected to a faucet and another 
hose connected from the load and stuffed into a sink drain.  A flow-valve 
contained a set of contacts used in series with the transmitter's interlock 
such that low flow resulted in the opening of the interlock -- which in turn 
kills RF output.  If flow is too low, the resistor will dissipate too much 
power and ultimately fail.

The transmitter was rated for a TPO of 25KW and the load was rated for a bit 
more than that.  The first time you see it in action, it's difficult to 
conceive that such a small load can safely dissipate so much power.  But, 
touch the exhaust water flow with your hands, and you'll feel a lot of heat. 
It's nowhere near boiling with reasonable flow, just very warm.

Paul, W9AC