Data: MediumMedium quality — at least 60% of universal parameters and pins are present, but some key data is missing. Verify specific values against datasheets before critical use.
Same Tung-Sol octal beam tetrode family. KT170 has much higher Pa_max (85W vs 60W). Same pin functions but different operating points and heater current.
Heater-to-Cathode Voltage (max)Cathode-Heater Voltage (max)300V
Notes
The Tung-Sol datasheet is notably incomplete: no explicit Va_max or Vs_max ratings are specified. The operating conditions limits section lists Pa_max, Ps_max, Ik_max, Vhk_max, and Rg_max but omits maximum plate and screen voltages. The plate characteristic curves extend to 500 V.
The datasheet specifies only a single SE operating point (Va=400 V, Vg2=225 V). No push-pull operating conditions are provided despite the 300 W PP claim.
Pin 1 is the outer metal screen (electrostatic shield). Pin 6 is empty (no physical pin). Pin 8 is cathode with beam-forming screen connected internally.
Heater current is specified as a range of 1.75–2.0 A. Radiomuseum.org lists a typical value of 1.85 A.
First grid cut-off voltage is −60 V (at Va=400 V, Vg2=225 V).
No triode-strapped operating data is published by the manufacturer. A diyAudio user (KoitoYuu) traced triode curves but did not publish mu, gm, or ra values. The user measured interelectrode capacitances in triode mode: Ck-g1=25 pF, Cg1-g2=18 pF, Ck-g2=20 pF.
Pin Layout — Octal
1Outer Metal Screen
2Heater
3Plate (Anode)
4
Socket-Compatible Tubes ⚠ Not electrically compatible