KT88 is a beam power tetreode, its anode limited dissipation power is 42W. In the audio amplifier, the power can be 100W when it is used as push-pull class AB1 with double tubes, it can also be used in electronic voltage regulator circuit. KT88 is similar with CV5220 and 6550,they can be replaced by each other.

Heater
UH………… 6.3 V
IH………… 1.6 A

Maximum Rating 
------------- --KT94 KT100 KT94 KT100
Ua……………… 800 800 800 800 V
Ug2………… 600 600 600 600 V
Ug1…………-200 -200 -200 -200 V
Pa………… 42 45 35 40 W
Pg2…… 8 8 6 6 W
Pa+g2… 46 49 40 45 W
Ik……………… 230 230 230 230 mA
Uh-k……… 200 200 250 250 V
Tbulb……………… 250 250 250 250 C

 Rg1
with cathode bias
--- ---Pa + Pg2≤ 35W 0.47 MΩ
--- ---Pa +Pg2 > 35W 0.27 MΩ
with fixed bias
--- ---Pa +Pg2≤35W 0.22 MΩ
--- ---Pa +Pg2> 35W 0.10 MΩ

Direct Interelectrode Capacitances

--- - - --triode connection and tetrode connection
input……… 16--- -9.3 PF
output……… 12 --- -17 PF
grid to plate……… 1.2 ----7.9 P

Static  parameter

tetrode connection
Ua…………………250V
Ug2……………… 250V
a………………… 140mA
Ig2(approx)…… 3mA
-Ug1(approx)……15V
Gm………………… 12mA/V
ri …………………12KΩ
μg1-g2…………… 8

triode connection
Ua.g2……………250V
Ia+g2……………143mA
-Ug1(approx)… 15V
Gm…………………12mA/V
ri…………………670Ω
μ………………… 8

Series KT88 KT94 KT100

  
 KT88-978

Recommended Operating Conditions（reference value)
Push-pull.classAB1.cathode bias.triode connection.

Ua.g2(b)………………400 485 V
Ua.g2(O)………………349 422 V
Ia+g2(0)………………2×76 2×94 mA
Ig+Ig2(max.sig)……2×80 2×101mA
RL(a-a)………………4 4 KΩ
-Ug(approx)………… 40 50 V
Pout………………… 17 31 W
Dtot ……………… 1.5 1.5 %
Pa.g2(0)…………… 2×26.5 2×40W
Pa.g2(max.sig)……２×19 2×27 W
Rk……………………2×525 2×525Ω
ū（g1-g1.pk）…… 78 114 V
Zout………………… 2 1.9 KΩ

Push-pull.classAB1.cathode bias.tetrode connection.

Ua(b)……………………560 V
Ua(0)……………………521 V
Ug2…………………… 300 V
Ia(o)……………………2×64 mA
Ia(max.sig)……………2×73 mA
Ig2(0)…………………2×1.7 mA
Ig2(max.sig)………… 2×9 mA
RL(a-a)……………… 9 kΩ
Rk……………………2×460 Ω
-Ug1(approx)…………30 V
Pout……………………50 W
Dtot……………………3 %
Pa(0) ………………2×33 W
Pa(max.sig) ………2×28 W
Pa2(0) ……………2×0.5 W
Pg2(max.sig) ……2×0.7 W
?(g1-g1.pk) ………60 V

                KT100 
Push-full.class AB1.fixed bias.ultra-linear connection.
（40%tapping points）
U a.g2(b)………………560 460 V
Ua.g2(0)………………553 453 V
Ia+g2(0)………………2ⅹ50 2ⅹ50mA
Ia+g2(max.sig)…… 2ⅹ157 2ⅹ140mA
RL（a-a）…………… 4.5 4 KΩ
-Ug1(approx)…… 75 59 V
Pout………………… 100 70 W
Dtot ………………………2 2 %
Pa+g2(0)………………2ⅹ27.5 2ⅹ27.5W
Pa+g2(max.sig)………2ⅹ33 2ⅹ27 W
ū（g1-g1.pk）…………140 114 V
Zout…………………… 7 6.5 KΩ

Push-full.class AB1.cathode bias.ultra-linear connection.
(40% tapping points)
Ua.g2(b) …………………500 375 V
Ua.g2(0) …………………436 328 V
Ia+g2(0) …………………2×87 2×87 mA
Ia+g2(max.sig) …………2×99 2×96 mA
RL(a-a) ………………… 6 5 kΩ
Rk…………………………2×600 2×400 Ω
-Ug1(approx) …………… 52 35 V
Pout…………………………50 30 W
Dtot……………………… 1.5 1.0 %
Pa+g2(0) ………………2×38 2×28.5 W
Pa+g2(max.sig) ……… 2×17 2×16 W
?(g1-g1.pk) …………… 104 71 V
Zout……………………… 4.8 4.5 kΩ

 
Push-full.class AB1.fixed bias.tetrode connection.
Ua(b) ………………………560 V
Ua(0) ………………………552 V
Ug2 ……………………… 300 V
Ia(0) ………………………2×60 mA
Ia(max.sig) ………………2×145 mA
Ig2(0) …………………… 2×1.7 mA
RL(a-a) …………………… 4.5 kΩ
-Ug1(approx) ………………34 V
Pout…………………………100 W
Dtot………………………… 2.5 %
Pa(0) ………………………2×33 W
Pa(max.sig) ………………2×28 W
Pg2(0) ……………………2×0.5 W
Pg2(max.sig) ……………2×4.5 W
?(g1-g1.pk) ……………… 67 V