KT88 GEC classic audio output pentodes CV5220 excellent shape quartet

KT88 GEC £ 1,200 Quartet


The KT88 with an anode dissipation of 35 Watts has been introduced by The General Electric Co. Ltd. in 1956

This valve is a higher-power version of the familiar KT66 although it is smaller in size. It does not replace the KT66, but is complementary to it for output powers in excess of those readily available from existing KT66 circuits.

The KT88 has a larger cathode, allowing for a higher mutual conductance, and a more modern type of construction permitting the use of higher anode voltages and dissipations. It. is designed for use mainly in a push-pull circuit and will operate satisfactorily as either a triode or a pentode.

The Kt88 you see here are early type and they all come with boxes

A good KT88 is tested with AVO 163 as follow:

Voltage filament 6.3 Volts

Anode and Screen 250 Volts

Negative grid -20

Good current should the 57 mA

Mutual conductance mA/V 8

KT88 here shown code 7312 7349 7315 7346. All four KT88 have Z on glass made at Hammersmith London UK

Have been tested at 69mA; 68mA; 69mA; 669mA full 100% emission and working order


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