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

Tue Mar 5 07:47:39 EST 2013

Jerry, the latter sockets were sealed so no moisture, etc. could penetrate 
the internal ring capacitor.

I replaced the two sockets in one of my KWS-1s and installed the newer 
sealed sockets.

Beware!

----- Original Message ----- 
From: "Jerry" <jsternmd at att.net>
To: "'Brett Gazdzinski'" <Brett.gazdzinski at verizon.net>; "'AM Radio 
Discussion List'" <>
Sent: Monday, March 04, 2013 11:19 PM
Subject: Re: [AMRadio] [AMRadio} 4cx250 / 4x150a socket wanted

>I don't know if attachments come through but the metal sockets made by 
>Eimac
> have different internal screen bypass caps - you cannot see them but they
> are there!
>
> Here's their datasheet quote:  " These sockets have hermetically sealed
> screen bypass capacitors to protect against moisture and dirt.
> The SK-6OOA socket has all base terminals brought out separately. The
> SK-61OA has cathode terminals 2, 4, 6 and 8 connected to the shell."
>
> Attached are the two datasheets.  Also these sockets are designed to allow
> forced air through the socket up thru a ceramic chimney (Eimac) SK606) for
> cooling.
>
> Jerry
> K1JOS
>
> -----Original Message-----
> From: Brett Gazdzinski [mailto:Brett.Gazdzinski at verizon.net]
> Sent: Monday, March 04, 2013 23:09
> To: Jerry; AM Radio Discussion List
> Subject: Re: [AMRadio] [AMRadio} 4cx250 / 4x150a socket wanted
>
> I read that.
> The metal socket I have has a cap on it, .001 at 1000 volts, the plastic
> sockets do not seem to have any cap that I can see.
> I am using the plastic socket, and it seems to work fine, no lack of highs
> on the audio, at least with plate modulation.
> With screen modulation, it did sound very bassy, but that might have been
> for other reasons.
>
> Brett
> N2DTS
> ----- 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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>

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Collins Radio Association
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