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Author Topic: 3-1000Z substitution  (Read 3392 times)
LU3FS
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Posts: 6




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« on: January 03, 2007, 10:20:23 AM »

My friend (LU1FA) have a lineal amplifier, similar to the BTI LK-2000.
It was built according to the article of the 1968 ARRL Handbook.
The inconvenience is it uses a valve 3-1000Z, which is expensive and difficult to get.
Which cheap Russian ceramic valve (GS-35b, or similar) can replace the 3-1000Z, with the change of the socket and the addition of a chimney
Keep in mind that the 3-1000Z current works with 3500 v in plate.
Any help, it is grateful.
73

Luis Bronzini
LU3FS
Rosario, SF
Argentina

P/D:
Excuseme my English, but the translating software is not friendly.
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WA4OBJ
Member

Posts: 57




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« Reply #1 on: January 03, 2007, 10:24:05 AM »

Go to the below website for information on using the GS35B.


http://gs35b.com/

Dave, WA4OBJ
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WA4OBJ
Member

Posts: 57




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« Reply #2 on: January 03, 2007, 10:59:20 AM »

Go to this one as well.


http://www.realhamradio.com/GS35B_Amp_Page.htm


Dave, WA4OBJ
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WA4OBJ
Member

Posts: 57




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« Reply #3 on: January 03, 2007, 12:01:30 PM »

I found one more site to look at:

http://n9adg.gs35b.com/

I think this has the information you need.  The author, Brian Moran N9ADG,  replaced a 3-1000Z with a GS-35B in a BTI LK-2000 amplifier.


"The work required to replace the 3-1000z with a GS35b consisted of:
- Remove the 3-1000z socket and filament transformer
- install gs35b socket, install gs35b filament transformer
- fashion clamps for plate, filaments (out of copper coated plumbing hangers and screws -- home depot)
- plug holes in sheet metal from anode cooling riser
- install W4ZT's bias circuit
- folks have recommended NOT to feed bias to the gs35b through the filament center tap, so I wound a new choke and fed the bias right to the cathode
- added a 'safety choke' across the output in the event of blocking cap failure"

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WB2WIK
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Posts: 21836




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« Reply #4 on: January 03, 2007, 01:31:42 PM »

The 4-1000 fits the same socket and has very similar ratings (except it's a tetrode).  Might not have as good IMD performance as 3-1000Z, but the 4-1000 will run grounded grid with grid and screen tied together, and people have been using the 4-1000 as a sub for the 3-1000Z for decades: It works.

4-1000's are plentiful; in fact, I buy them as pulls for $100 each and they always seem to work.  The one I have in my 6m amplifier was a pull (from an FM broadcast transmitter) in 1984 and still works fine 22 years later.

WB2WIK/6
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SSB
Member

Posts: 1




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« Reply #5 on: January 12, 2007, 06:09:08 PM »

3-1000z tubes are not hard to find.  RF Parts sells them and there always seems to be one or two on Ebay.  I wouldn't use those Russian tubes if you gave them to me.  A brand new 3-1000z from Eimac (nos) or Triton costs about $650 and they are worth it.  You can't destroy the tube if you tried.  If you find a good used one and then look for a cheap spare when available, you can have your 3-1000z for very low cost that will last you forever. It just takes a little patience. The very first amp I build in 1968 used a brand new tube I bought from Barry's in NY for $60, and I think the person I sold it to still is using the original 3-1000z tube.

Alex.....
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