TUBE: KT66
FICHIER SOURCE: sheets/126/k/KT66.pdf
FABRICANT: Marconi's Wireless Telegraph Company Limited
ANNEE: JUNE 1956
TYPE DECLARE: BEAM PENTODE (6.3V indirectly heated) — [en réalité beam tetrode, voir note typologie]

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MARCONI — KT66 — BEAM PENTODE — 6.3V INDIRECTLY HEATED — JUNE 1956
BASE CONNECTIONS AND VALVE DIMENSIONS:
  Base: International Octal
  Bulb: Dome top tubular
  Overall length: 125-135 mm
  Seated length: 111-121 mm
  Max. diameter: 53 mm
Pinout (view from underside of base):
  Pin 1 = N.C.
  Pin 2 = h (heater)
  Pin 3 = a (anode)
  Pin 4 = g2 (screen)
  Pin 5 = g1 (control grid)
  Pin 6 = N.P.
  Pin 7 = h (heater)
  Pin 8 = k (cathode)
RATING — Pentode Connection:
  Vh ... 6.3 V
  Ih ... 1.27 A
  Va ... 500 V
  Vg2 .. 400 V
  Pa ... 25 max. W
  Pg2 .. 3.5 max. W
  ra (at Va=Vg2=250, Vg1=-15) ... 22.5 kΩ
  gm (at Va=Vg2=250, Vg1=-15) ... 6.3 mA/V
RATING — Triode Connection:                  Va=400      Va=250
  Va .................................. 400         250        V
  pa .................................. 28.5        28.5       W
  ra (Va=400,Vg1=-38 / Va=250,Vg1=-19) 1.45        1.3        kΩ
  gm (Va=400,Vg1=-38 / Va=250,Vg1=-19) 5.5         6.15       mA/V
CAPACITANCES (of unscreened valve):
  Cg1-all ... 16 pF
  Ca-all .... 11.5 pF
  Ca-g1 ..... 1.1 pF
TYPICAL OPERATION — Single Valve. Class A. Triode Connection:   (col1 / col2)
  Va,g2 ........... 250 / 400 V
  Vg1 (approx) .... -19 / -38 V
  Ia,g2 ........... 60 / 63 mA
  vin (pk) ........ 19 / 38 V
  pa,g2(o) ........ 15 / 25 W
  Rk .............. 315 / 600 Ω
  RL .............. 2.75 / 4.5 kΩ
  Pout ............ 2.2 / 5.8 W
  D ............... 6 / 7 %

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Push-Pull. Class AB1. Triode Connection (Two Valves). Data per pair:   (col1 / col2)
  Va,g2 ........... 250 / 400 V
  Vg1 ............. -20 / -38 approx. V
  Ia,g2 ........... 110 / 125 mA
  vin(pk)(g1-g1) .. 40 / 80 V
  Rk (per valve) .. 360 / 600 Ω
  RL(a-a) ......... 2.5 / 4 kΩ
  Pout ............ 4.5 / 14.5 W
  D ............... 2 / 3.5 %
Single Valve. Class A. Pentode Connection:
  Va ........ 250 V
  Vg2 ....... 250 V
  Vg1 ....... -15 approx. V
  Ia ........ 85 mA
  Ig2 ....... 6.3 mA
  vin(pk) ... 15 V
  Pa(o) ..... 21.5 W
  Rk ........ 160 Ω
  RL ........ 2.2 kΩ
  Pout ...... 7.25 W
  D ......... 9 %
Push-Pull. Class AB1. Pentode Connection (Two Valves). Data per pair:   No signal / Max signal
  Va .............. 250 / 250 V
  Vg2 ............. 250 / 250 V
  Vg1 ............. -17.5 approx. / — V
  Ia .............. 162 / 165 mA
  Ig2 ............. 12 / 20 mA
  vin(pk)(g1-g1) .. — / 36 V
  Pa (per valve) .. 20 / 12 W
  Pg2 (per valve) . 1.5 / 2.5 W
  Rk (per valve) .. 200 / 200 Ω
  RL(a-a) ......... — / 4 kΩ
  Pout ............ — / 17 W
  D ............... — / 4 %
Push-Pull. Class AB1. Pentode Connection (Two Valves):   No signal / Max signal
  Va(b),Vg2(b) .... 450 / 425 V
  Va .............. 415 / 390 V
  Vg2 ............. 300 / 275 V
  Ia .............. 104 / 125 mA
  Ig2 ............. 5 / 18 mA
  vin(pk)(g1-g1) .. — / 70 V
  Pa (per valve) .. 21.5 / 9.5 W
  Pg2 (per valve) . 0.75 / 2.5 W
  Rk (per valve) .. 500 / 500 Ω
  RL(a-a) ......... — / 8 kΩ
  Pout ............ — / 30 W
  D ............... — / 6 %
  Va(rms)(to rectifier) ... — / 500+500 V
  Rsource (HT) ............ — / 600 Ω

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Push-Pull. Class AB1. Pentode Connection. Fixed Bias (Two Valves). Data per pair:  No signal / Max signal
  Va .............. 510 / 475 V
  Vg2 ............. 395 / 360 V
  Vg1 ............. -40 approx. / — V
  Ia .............. 80 / 175 mA
  Ig2 ............. 3 / 19 mA
  vin(pk)(g1-g1) .. — / 80 V
  Pa (per valve) .. 21 / 17 W
  Pg2 (per valve) . 0.6 / 3.5 W
  RL(a-a) ......... — / 5 kΩ
  Pout ............ — / 50 W
  D ............... — / 5 %
  Screen grids supplied from stabilised source.
GENERAL: Series resistor 100/300Ω close to screen grid terminal for parasitic oscillation. When triode connected, between screen grid and anode. Control grid series resistor 10/50kΩ recommended.
  Max permissible DC resistance grid-cathode: 0.5 MΩ auto-bias, 0.1 MΩ fixed bias.
SCREENING: No internal or external screening fitted to the valve.
MOUNTING: Any position.
RETAINING: No retaining device normally necessary.
VENTILATION: Adequate ventilation around the bulb should be provided.

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[courbes seules — Pentode Connection Vg2=400: Ia(mA) vs Va, Vg1=0 à -50]

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[courbes seules — Pentode Connection Vg1=0: Ia vs Va, Vg2=50 à 300. + Triode Connection: Ia vs Va, Vg1=0 à -120]

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[courbes seules — Pentode Connection Vg2=300: Ia vs Va, Vg1 +10 à -40. + Pentode Connection Vg2=250: Ia vs Va, Vg1 +10 à -35]

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[courbes seules — Pentode Connection Single Valve Class A (Va=250,Vg2=250,Ia=85mA,RL=2.2kΩ): Pout & D vs vin(pk). + Triode Single Valve Va=250]

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[courbes seules — Triode Connection Single Valve Class A Va=400: Pout & Dtot vs vin(pk)]

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[courbes seules — Triode Connection 2 valves Push-Pull Class AB1 Va=250 et Va=400: Pout & Dtot vs vin(pk)(g1-g1)]

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[courbes seules — Pentode Connection 2 valves Class AB1 Push-Pull Va(o)=415 Vg2(o)=300: D% & Pout vs RL(a-a) et vs Normal Supply Voltage]