[AMRadio] [AMRadio} 4cx250 / 4x150a socket wanted

[David Knepper]

If you look carefully at these tube sockets you might see a layer of 
insulation between the metal rings - those are the insulating materials for 
the capacitor that is an integral part of the socket.

Jerry is correct that the bypass capacitor is within the socket.


----- Original Message ----- 
From: "Jerry" <jsternmd at att.net>
To: "'Brett Gazdzinski'" <Brett.gazdzinski at verizon.net>; "'AM Radio 
Discussion List'" <amradio at mailman.qth.net>
Sent: Monday, March 04, 2013 10:41 PM
Subject: Re: [AMRadio] [AMRadio} 4cx250 / 4x150a socket wanted


> Hi Brett,
>
> I am no amp expert but you do know that there are several different 
> versions
> of the 4CX250b sockets?  Some with no built in screen bypass cap and 
> others
> with different by-pass values?  I believe the 600 and 600A have a 3700pf
> screen bypass within the socket.
>
> 73 Jerry
> K1JOS
>
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Brett Gazdzinski
> Sent: Monday, March 04, 2013 22:12
> To: AM Radio Discussion List
> Subject: Re: [AMRadio] [AMRadio} 4cx250 / 4x150a socket wanted
>
> I had a nice QSO on 40 meters with w3mtg (I think it was) last month, and 
> he
> was running a screen modulated 4cx250b that sounded great, so I thought I
> would build a 4cx250b rf deck to experiment with.
> It came out very well, I just swappedit out for my 3x 4D32 rf deck and 
> used
> the same control deck.
> Everything is metered and adjustable, so its handy for experiments.
> I put various transformers in the screen feed and adjusted things in every
> way, and it sounded nasty no matter what I tried.
> At best, you could understand my speech, but it was nasty.
> As another experiment, I turned on the modulator (pair of 811's) and it
> worked very well.
> At 1200 volts I get close to 200 watts out, and it modulated very well.
> So I want to rebuild it with two tubes in it, but i only have 2 sockets, 
> one
> all metal thing, and one plastic (green?) one that mounts with about 8
> screws.
> The metal one seemsto have no mounting screws or holes???
>
> I will trade one for the other, or other parts, but I need two matching
> sockets.
>
> Brett
> N2DTS
>
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David Knepper, W3CRA/W3ST
Collins Radio Association
www.collinsra.com
Join the CRA today