E.A.T. KT88 Diamond Valve

A KT88 tube that is in a league of it's own. This KT88 tube is available in factory-matched quartets. It's construction features include black plates, black metal base, and gold pins.

The E.A.T. KT88 has an designed maximum anode dissipation rating of 35W and is recommended for use in the output stage of an a.f. amplifier. Two valves in class AB1 give a continuous output of up to 100W. The KT88 is also suitable for use as a series valve in stabilized power supply.

Valve Type: *KT88 DIAMOND*
Size – included socket: 5.2 × 12.5 cm / 2 × 4.9 inch

Characteristics:

Plate dissipation (Max.): 40 W
Grid dissipation (Max.) : 6 W
Cooling: radiation
Heater – Voltage: 6.3 V
Heater – Current: 1.6 A

Maximum ratings:

Anode voltage: 800 V
Screen grid voltage: 600 V
Va, g2: 600 V
- Vgl: 200 V
Pa: 35 W
Pg2: 6 W
Pa + g2: 40 W
Ik: 230 mA
Vh -k: 200 V
Tbulb: 250 °C

Capacitances (measured on a cold unscreened valve)

Triode connection
- Cgl -a, g2: 7.9 pF
- Cg1 -all less a, g2: 9.8 pF
- Ca, g2 -all less g1: 17 pF
Tetrode connection
- Cg 1 -a: 1.3 pF
- Cg 1 -all less a: 17 pF
- Ca -all less g1: 12 pF

Push – Pull, Class AB 1, Cathode Bias, Ultra – Linear Connection (40% Tapping Points).

Vag2 (b): 500 – 375 V
Vag2 (o): 436 – 328 V
Ia + g2 (o): 2 × 87 – 2 × 87 mA
Ia + g2 (max. sig): 2 × 99 – 2 × 96 mA
RL (a-a): 6 – 5 k Ohms
Rk^*: 2 × 600 – 2 × 400 Ohms
- Vg1 (approx.): 52 – 35 V
Pout : 50 – 30 W
Dtot: 1,5 – 1 %
I.M.D. : 4 – 3 %
Wa + g2 (o): 2 × 38 – 2 × 28.5 W
Wa + g2 (max. sin): 2 × 17 – 2 × 16 W
V g1 – g1 ac: 104 – 71 V
Zout: 4.8 – 4.5 k Ohms*

^*It is essential to use two separate cathode bias resistors. I.M.D. intermodulation distortion measured using two input signals at 50 and 6000 Hz (ratio of amplitudes 4:1)

Push – Pull, Class AB 1, Cathode Bias, Triode connection.