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Re: Really big VTTCs

Original poster: David Speck <Dave@xxxxxxxxxxxxxxxx>


A quick scan of eBay shows lotsa choices, both used, or new with warranties. One of them is even starting at $1.00! The matching sockets are also there as well, some for as little as $25.00. The H3 version doesn't even need a socket -- it has flying leads.
Eimac 3CX10,000A7 Linear RF Power Amplifier Tube 8160 : 290073180762

NEW!!!! EIMAC/VARIAN 3CX10/000B7 AMPLIFIER TUBE : 160077347739

Eimac 3CX10000H3 3CX10,000H3 RF Vacuum TUBE : 140076841087

I've read that the tetrodes are a little less convenient, but still usable by connecting the grids:

Used very good Eimac 4CX5000 Tested : 110082360349    (starting at $1.00)

4CX10000D Eimac made in USA (Used but working ok) : 9737662160 ($330 Buy it NOW!)

Rebuilt 4CX10000D Transmiter Tube: 260078009338

4CX10000 D Eimac NEW (NOT USED): 5859483842    (BIN for $1300)

Bigger yet:

4CX15000A Eimac made in USA (Used but working ok) : 170000738182 (BIN for $375)

and for the really power hungry -- brand new!:

4CX 40,000 GM EIMAC VALVE : 5825883410 ( A steal at over $8,000, but this dealer is always very high priced!) Imagine 40 kW dissipation!

If I know how to design the rest of the coil, I might consider grabbing the 4CX15000 -- seems like a good price for plenty of power.

Tesla list wrote:
Original poster: "resonance" <resonance@xxxxxxxxxxxx>

I'm all ears.

Can you suggest a nice surplus tube that would handle 10 kVA at around 7.2 kV? I'm thinking of a small 7.2 kV, 10 kVA pole xmfr for power. Perhaps two big 10 kVA tubes running at 20 kVA into a 24 inch dia. coilform approx 72 inches long. 34 x 8.5 inch toroid. Perhaps with John's stattaco controller on the tubes.


Dr. Resonance

By comparison, VTTCs seem to have topped out at a 4" x 20" secondary, driven by one to four 833A tubes. The consensus seems to be that you can get just about as good performance from one 833A as with 4 of them, if you design the coil right. Perhaps 36" discharges seem to be the limit for VTTCs on a good day.
Is there some physical or electronic limitation to the design and construction of a really big VTTC? With the availability of big surplus power tubes (10 kW or more) on eBay, and the possibility of multiple parallel free MOTs for input power, is there a physical reason why no one has built a 12 x 60 or 18 x 90 VTTC?
Ten foot sword like discharges would be neat to watch!