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4-1000A.jpg (12107 bytes)

Hello All,

This is my new project an 80 -10 meter band switchable HF amp using a 4-1000A. I will be adding to this page as I proceed with the project. So check back often.

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Reason for using this tube:

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Basic Design

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The Power Supply

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The amp circuit

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Tube Data

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  Part list

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 Part Suppliers

 

 

 

 

Reason for using this tube:

bulletlow cost :(about $200.00) check prices at Thomas J. Bruckner here on the web.
bulletLong Life : estimates of about 30 years at plate voltages of 5KV running 1.5kw.  Look here for feedback from homebrews about this tube.
bulletA 4CX-10000 will work in the circuit with little modifications.

 

 

 

Basic Design:

The Power Supply

Start with a good transformer.  This tube really likes about 7200v on the plate, but the output there would be about 3500 - 4000 watts.  The up side to the higher voltage would be lower drive for legal limit output.  I went with a 5KV transformer at 1 amp, because of price to output to drive requirements. This voltage should yield a good 1.5KW output with 100 watts of drive. You will also need a filament transformer of 7.5 volts @ 21 amps, these can be purchased at Peter W. Dahl Co.

The basic diagram for the high voltage supply is shown below:

 

The amp circuit:

Tube Data:

GENERAL DESCRIPTION


  The 4-1000A / 8166 is intended for use as an amplifier, oscillator, or modulator and is capable of efficient operation well into the VHF range.
Cooling of the tube is accomplished by radiation from the plate and by circulation of forced-air through the base and around the envelope. Cooling can be simplified through the use of a SK-510 Air-System Socket and its accompanying glass chimney.


TECHNICAL SPECIFICATIONS
Plate Dissipation (Max.) 1000 watts
Screen Dissipation (Max.) 75 watts
Grid Dissipation (Max.) 25 watts
Frequency for Max. Ratings (CW) 110 MHz
Cooling Radiation & Forced Air
Filament
Voltage
Current
Thoriated Tungsten
7.5 volts
21.3 amperes
Capacitances (Gnd. Cath. Connection)
Input
Output
Feed-through

28.1 pF
8.1 pF
0.3 pF
Amplification Factor (g1-g2) 6.9
Transconductance 10,000 µmhos
Base 5-Pin Special
Recommended Air-System Socket SK-510
Recommended Air Chimney SK-506
Recommended Heat Dissipating Connector HR-8
Maximum Seal Temperature 200°C
Maximum Envelope Temperature 225°C
Maximum Length 9.63 in; 244.60 mm
Maximum Diameter 5.25 in; 133.30 mm
Weight (approximate) 1.5 lb; 0.68 kg
Operating Position Vertical, base up or down

 

I am staring with a diagram form "Radio Handbook -- twenty-first edition, by William I. Orr, W6SAI. pg. 22.13

4-100 dia.GIF (15790 bytes)

This amplifier is a grounded grid configuration.  This makes this tube a little harder to drive, but  the more plate voltage the lower driving wattage needed with output remaining constant.    With the voltage of 5KV, and 125 watts of drive, should make the output of  this tube over 1.5KW. If you need to drive this tube with lower wattage you may want to use grid drive, see Richard Measures page for details on how to set up grid drive for a tube.

Part list

Below you will find the parts I used in my 4-1000 amp. I use the vacuum variables captors, because of the higher voltage used on the plates

 

 

 

 

 

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Randy Adams
Copyright © 1999 Charles R Adams. All rights reserved.
Revised: March 17, 2002..