EAT - Exceptional Audio Tubes - KT88 Diamond Vacuum Tube- Matched Quad Box Set

The E.A.T. KT88 has a 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 a stabilized power supply. The EAT KT88 is one of the best KT88 tubes in production. For a KT88 review. 

• 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.

• Vag2 (b): 400 – 485 V
• Vag2 (o): 349 – 422 V
• Ia + g2 (o): 2 × 76 – 2 × 94 mA
• Ia + g2 (max. sig): 2 × 80 – 2 × 201 mA
• RL (a – a): 4 – 4 k Ohms
• -Vg1 (approx.): 40 – 50 V
• Pout: 17 – 31 W
• Dout: 1.5 – 1.5 %
• I.M.D.: 5.6 – 5.6 %
• Wa + g2 (o): 2 × 26.5 – 2 × 40 W
• Wa + g2 (max. sin): 2 × 29 – 2 × 27 W
• V g1 – g1 ac: 78 – 114 V
• Rk: 2 × 525 – 2 × 525 Ohms
• Zout: 4.8 – 4.5 k Ohms

I.M.D. intermodulation distortion measured using two input signals at 50 and 6000 Hz (ration of amplitudes 4:1).

Sold as a Matched Quad Box Set (4x KT88 Tubes)