[AMPS] Re: [Amps] CW Amplifier progress (well, daydream progress) -- long

[Vic Rosenthal]

Peter Chadwick wrote:
> 
> Especially if you're only looking for 1500watts of CW, why not 4CX250B's? 4
> of them, 2kV at an amp or so, and you're there. You should be able to pick
> them up reasonably cheaply with sockets. Over here, I'd reckon to get
> sockets and 4 tubes for under $150. 

I thought about this.  My investigations so far haven't lead me to any cheap
ones.  They may be out there, but the prices I've seen so far have been quite
high.  Unfortunately, I can't ask for a guarantee on flea-market tubes for an
amp that I haven't built yet, so I need to get them from a reliable source.

> Do you really need instant on?

I can live without it.  It's just one point in favor of filament-type tubes.  Of
course, the other side of the coin is that the filament current is higher,
requiring a big transformer and filament choke.
 
> The big advantage of 3-500Zs to my mind is that the blower requirements are
> such that it's likely to be reasonably quiet.

My SB1000 uses a muffin fan to cool the tube and seems quite noisy.  I would
like the one I'm building to be quieter.  

73,
Vic, K2VCO
Fresno CA

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