Tung-Sol KT170 Power Tube

A high-dissipation octal beam tetrode with 85 W maximum plate dissipation, a 6.3 V heater, and the size and current capability required for serious high-output tube amplifiers

The Tung-Sol KT170 is the biggest bottle in the modern Tung-Sol beam-tetrode family, built for amplifiers that need more than a conventional KT88-class output tube can comfortably deliver. If your amplifier was designed around the KT170, this is the tube you reach for when the brief is simple: more power handling, more reserve, and more ease under load.

Like the KT150, the KT170 uses an octal base and a large glass envelope, but it steps up to an 85 W maximum plate dissipation rating. That higher dissipation ceiling is what makes the KT170 matter in real-world amplifier design. It gives engineers more thermal margin and more headroom to build high-output tube amplifiers without pushing the tube as hard at the edge of its envelope.

This is not a drop-in replacement for just any amp. The KT170's physical size, 6.3 V heater requirement, and roughly 1.75–2 A heater current draw mean amplifier compatibility needs to be confirmed first. But in an amp designed to use it, the KT170 is exactly the kind of output tube that makes sense in a serious high-power valve rig. Call us if you want to be sure your amplifier is ready.

Built for Big Output Stages

The KT170 is a beam tetrode intended for low-frequency amplification in hi-fi output stages. In plain English, this is a purpose-built output tube for amplifiers that are expected to produce substantial power while still behaving like a proper tube amplifier should: stable, controlled, and unflustered when the music gets demanding.

High Plate Dissipation

The headline spec here is the 85 W maximum plate dissipation rating. That is the key differentiator, and it is the reason the KT170 exists. More plate dissipation gives an amplifier designer more room to work with, which can translate into greater output capability and less sense of strain in amps engineered to exploit it properly.

Large-Bottle Tung-Sol Design

The KT170 uses a distinctive original-shaped glass bulb and octal base, with a maximum diameter of 68 mm and overall height of 150 mm. That larger envelope is part of what allows the tube to operate in these higher-power applications, but it also means chassis clearance matters. Before ordering, make sure your amplifier has the physical room and heater supply capacity to run KT170s correctly.

Features

• Tung-Sol KT170 beam tetrode power tube
• Designed for hi-fi audio output-stage applications
• 85 W maximum plate dissipation
• 6.3 V heater requirement
• Approximately 1.75–2 A heater current draw
• Octal base for use in compatible tube amplifiers
• Large original-shaped glass bulb for high-power operation
• Best suited to amplifiers specifically designed around KT170 electrical and physical requirements

Specifications

Tube Type: Beam Tetrode

Base: Octal

Maximum Plate Dissipation: 85 W

Heater Voltage: 6.3 V

Heater Current: 1.75–2 A

Maximum Diameter: 2.7" (68 mm)

Overall Height: 5.9" (150 mm)