Re: {Collins} Cetron 811A Blues and Surplus Sales



For what it's worth, I purchased a set of those Cetron 811A's from SSoN five years ago.  I tested them in the TV-7 upon arrival to verify they weren't DOA, but nothing further.  I did notice they had a 1980's date code, and did not have the small ceramic spacer between the glass and plate cap like some (not all) older RCA 811A's.  There has been some discussion here and elsewhere in the past, about vacuum tube quality going steadily downhill in the 1980's as production in this country weaned off and ceased.  

Anyway-  That project sat, and the tubes were not installed in a 30L-1 until about two years ago.  They have worked for me just fine since, primarily on 10 meters, no less.  If I ever have to get in there I'll have to see if the plate cap and base cement has failed due to heat, time, etc.  I would not be the least bit surprised if the cement used on 1980's production tubes is inferior to what was used in decades past.  

In either event, I wouldn't hold the dealer accountable, unless they were found to be loose or defective straight out of the box.
Just for fun, here is an excerpt found on the interwebs about a tube base cement formula from Max Knoll's "Materials and Processes of Electron Devices," Springer-Verlag, 1959:

Pitch (higher hydrocarbons)
Litharge (5-6 parts litharge, 1 part pure glycerine)
Marble cement (5 parts gypsum and alum. baked, 2-3 parts water)
Graphite-silicate of soda (1 part graphite, 5 parts Kaolin, 5-6 parts 
 (sodium silicate of soda)
Shellac cement (gypsum or other fillers, shellac diluted in alcohol 1:1)
Thermoplastic cement (marble powder, laccain (novo-lacquers) diluted in
 alcohol)
Resol (2 parts calcite, kaolin, or whiting, 1 part resol (Bakelite varnish))
Bakelite cement (75-90% calcite, whiting, 5-10% thermosetting phenolaldehyde
 resin (Dow Corning 2103))
 [This seems to make 80-100% of the recipe!]
Siemens and Halske (65-70% calcite, whiting, 20-25% silicone resin solute
 (H.K. 15, Wacker Chemie), remainder solvent (xylol))
My .02 and only comments on the situation. 

Regards, 
Chris kc9ieq
      From: Tom <url4603rd@xxxxxxxxxxx>
 To: Bill Carns <wcarns@xxxxxxxxxxxxx>; 'James Bledsoe' <jamesbledsoejr@xxxxxxx>; collins@xxxxxxxxxxxxx 
 Sent: Monday, May 25, 2015 6:27 PM
 Subject: Re: {Collins} Cetron 811A Blues and Surplus Sales
   
Bill,

    Then lets stay with the facts as stated. There are at least 3 
people that have had exactly the same problems, in recent history,  with 
these tubes. Relating these facts on their face is an act of "bad 
mouth"? I said not a word until another user posted the exact same 
problem as I had. Then within minutes another posted that they also had 
the same exact problems.

    Personalities, aside, do you not agree that there may be a chance 
of a problem with the tubes? Others may or may not come forward, given 
the "That will earn you moderation or worse. " statement?

73, Tom Nicholson W1ALZ (KA1BAZ)



On 5/25/2015 6:52 PM, Bill Carns wrote:
> Well,  I will ring in here also..  I have dealt with Bob at Surplus Sales
> for over 20 years and he is a "Stand Up" guy and so is his business.  There
> are always two (at least) sides to any story.  Bob has a huge industrial
> surplus and supply business and the "Collins" support work is a very small
> part of his business which he maintains as a favor for the collecting
> community.  He is very ethical and I know that he cares about not only his
> reputation, but his ethical behavior..  So, in that light, see the
> possibility of the "two sides" version and let's let the guys directly
> involved in this deal with it as they think they should...
>
> But, let's not start a "bad mouth: job on SSoN or the people involved.  That
> will earn you moderation or worse.  That is never allowed on this reflector.
>
>
> Bill Carns, N7OTQ (Trustee K0CXX)
> Past President, Collins Collectors Association
> Founding Board, Collins Radio Heritage Group
> Editor, Signal Magazine
> Wimberley, TX
> 512 618 2762  (Cell)
> 512 847 7010  (Home)
>
>
>
>
>
> -----Original Message-----
> From: Collins [mailto:collins-bounces+wcarns=austin.rr.com@xxxxxxxxxxxxx] On
> Behalf Of Tom
> Sent: Monday, May 25, 2015 4:59 PM
> To: James Bledsoe; collins@xxxxxxxxxxxxx
> Subject: Re: {Collins} Cetron 811A Blues and Surplus Sales
>
> This REALLY caught me of guard, as I've been in this "Collins" thing for
> many years ( some of you may know me by my previous call of KA1BAZ) and many
> moons ago was part of the Net Control operators for the Sunday net.
> Back when Bud Whitney was in his prime. I'll miss him greatly.
>
> Surplus Sales was a "stand up" company to work with (back in the day) BUT I
> guess things have changed?  The 811A's that they are selling MAY say Cetron
> on them but I'm of the believe that they just might be "knock offs"??? Just
> asking.
>
> 73, Tom W1ALZ
>
>
> On 5/25/2015 5:08 PM, James Bledsoe via Collins wrote:
>> Well, at least I know I am not the only person those guys are rude
>> too. Incredible.
>>
>> TNX es 73 de Jimbo KK5GG..sk
>>
> *** You are subscribed to Collins as wcarns@xxxxxxxxxxxxx. If you wish to
> unsubscribe, or modify your preferences please visit
> http://mailman.listserve.com/listmanager/listinfo/collins ***
>
>

*** You are subscribed to Collins as kc9ieq@xxxxxxxxx. If you wish to unsubscribe, or modify your preferences please visit http://mailman.listserve.com/listmanager/listinfo/collins ***





This archive was generated by a fusion of Pipermail (Mailman edition) and MHonArc.