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[Amps] Fwd: Amps Digest, Vol 89, Issue 22

Subject: [Amps] Fwd: Amps Digest, Vol 89, Issue 22
Date: Fri, 14 May 2010 20:38:28 EDT
List-post: <">>
I have a 3CX1200Z7 tube, that has a 6.3 vac fil. Has three pins for fil  & 
cathode and a grid ring around the middle to ground the grid. Any tube has  
to go thru a gettering process before putting B+ or RF to the tube. Google: 
How  to Getter a vacuum tube. Willy K3VW
Sent: 5/14/2010 3:00:17 P.M. Eastern Daylight  Time
Subj: Amps Digest, Vol 89, Issue 22

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Today's Topics:

1. Hombrew 3-1000Z  in SA (Patrick Barthelow)
2. air director  (Herzog)


Message:  1
Date: Thu, 13 May 2010 16:36:29 -0700
From: Patrick Barthelow  <>
Subject: [Amps] Hombrew 3-1000Z in SA
To:  <>
Message-ID:  <SNT115-W88E67663C2019484E60A2DFFC0@phx.gbl>
Content-Type:  text/plain; charset="iso-8859-1"


As most of you have  read, I am seeking an amp for a friend in Uruguay, via 
almost any mechanism  that is minimal cost.  Basket cases, tubes, parts, 

Come to the conclusion that most has to be found, or originate in  country, 
due to very stiff duties (apparently ~100% of new paid value) paid,  or 
shipping costs for heavy items.

I wonder if duties can be  waived or reduced if bring in is accompanied, 
with a strong letter of  endorsement by the national Amateur Radio Body, 
explaining the emergency  comms, public service aspects of amateur radio. with 
reference to the specific  person receiving the item?

I found a single  3-1000Z  nicely built amp with separate power supply, now 
for sale by family of an SK  ham in Uruguay.    

Has not been powered up for at least 2  years, when the SK ham passed away.

See  Photos:

I  love the big bottles, but dont know any specific  gotchas on the  
3-1000Z.  So, looking for exprienced feedback on the  3-1000Z.  :

1. Are 3-1000Zs  prone to failure due to gas intrusion through  the 
glass/metal seals, with dormancy/non use,  like the 3-500Z?

2.  Can an old stored 3-1000Z be rejuvinated in the usual way, burn in, low 
B+  gradual increase, getting the plate hot?

3.  What is the  availability of replacement 3-1000Zs New or used?

4.  If this is  the last practicaly obtainable 3-1000Z in the country,   
what modern  external anode triode might be a electrically similar tube, using 
similar B+  and having similar Plate Z in amateur operation,  that could be 
swapped  (with rebuild, redesign of the tube mount, and fil transfomer 
change) into the  amp if this 3-1000Z fails?   (maybe the GS-35B?) 

5. Is it a  good idea to design a filament cold start circuit, or perhaps a 
small variac  to bring the filament voltage on to try to get maximum years 
out of the  tube?
I think I remember a 7.5 V  21 Amp fil requirement.  Pretty  good THUNK!  
when you turn on filaments, I bet.

6. Can 100  watts input drive them to Legal Limit?  With a tuned input?  
Without  a tuned input?  

7. What is the input Z if direct fed,  without a tuned input circuit?

Thanks for all  your prior  valuable input.

Best Regards,   
73, de Pat Barthelow  AA6EG

Hotmail  has tools for the New Busy. Search, chat and e-mail from your  


Message:  2
Date: Thu, 13 May 2010 19:48:53 -0400
From: Herzog  <>
Subject: [Amps] air director
To: Ham-amps  <>
Message-ID:  <>
Content-Type: text/plain;  charset=ISO-8859-1; format=flowed

Somebody wanted this, My computer  lost messages as mail program updated. 
I got the box, but no  address to send it to.

Eimac's "epoxy-like" cone that puts air from  chassis/tube socket to tube 
like 4CX10000.  Anyone want?  K2LB.  585-482-6151 or e-mail.
Ps, it is 7-3/4 inch tube, 8.5 inch diameter at  bottom, and 9 inch bolt 
circle for the 4  mounts.


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