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CV3340 high power X-band klystron amplifier

This valve measures 470x220x220mm overall and weighs around 40kg

This is a high power X-band 4-cavity broadband klystron amplifier.

Heater power27.6 to 37.2W
Heater resistance at 32W3.1 to 3.4 ohms
Cold heater resistance0.2 ohms
Max switch-on surge current9A
Min heating delay time3 mins
Max beam voltage13kV
Max beam current700mA
Max power output3kW
Operating bandwidth *8GHz to 9GHz
Valve bandwidth16MHz
Min water flow through block at 20°C1.5l/min
Min water flow through collector at 20°C6l/min
Pressure drop through block at 1.5l/min0.5 lbs/
Pressure drop through collector at 6l/min4 lbs/
Pressure drop through block at 6l/min4 lbs/
(The block and collector can be run in series with a 6l/min water flow. The water must enter the block first.)
Typical operation
Beam voltage13kV
Beam current530 to 600mA
Magnetic field1500 to 1700 Gauss
Output powernot less than 2kW
Efficiency33 to 38%
RF gain32 to 47dB
Loss current, no RF at 13kVnot more than 3% of beam current
Loss current, 2kW at 13kVnot more than 100mA

*: the valve is supplied pre-tuned to any frequency in this band

The valve must be mounted cathode down (as in the main photo)

CV3340 is one of a series of CV numbers which have no entry at all in in the CV Register, which has a gap after CV2999 up to CV3499.

The label on this valve says CV3340, serial L2006LAB 8509, and the code KFRR. Looking at K1001, 'F' is not listed as a qualification approval letter, but the manufacturer code RR indicates Ferranti. The Ferranti part number for this is SY41.


The valve is surrounded by a powerful magnet and has electrical connections for 'heater' and 'block', plus one which appears to have a missing label. The 'block' connector seems to be electrically connected to the frame, while the other is connected to the metalwork which can be seen between the two connectors in the right hand photo below. It has cooling ports for 'collector' and 'block'.


The pipework connects internally via a mix of metal and rubber pipes.


There are two ports under the device. The output port is nearest the cooling ports, and the input port nearest the cathode. Each connects separately to the internal structure. The aperture size is 28x17mm.

Base viewPorts

Below is a side view of the ports between the frame and the magnets. Below that are photos of the internal structure showing the rear of the ports connecting in.


The internal structure can be viewed through two removable (glued) plastic covers revealing what appears to be tuning slugs.