McIntosh KT88, beam tetrode tube for power amplifiers

The KT88 is a beam power tube for the output stage of appropriately designed audio amplifiers. Its task is to amplify the previously prepared music signal with the current required for power delivery. In McIntosh devices, it works together with an output transformer.

In addition to the cathode, control grid, screen grid, and anode, the design uses additional beam-shaping plates. These focus the electron flow and influence the behavior of the tube within the output circuit. The octal base has a central guide for unambiguous orientation in the tube socket.

The achievable output power depends on the entire amplifier circuit. Operating voltage, operating point, number of tubes, and output transformer are crucial for this. The KT88 therefore has no generally valid audio power in watts that could be specified independently of the amplifier.

McIntosh uses the KT88, for example, in the MC275 and in the tube section of the MC451. The required replacement components depend on the respective model. With multiple power tubes, a selection with comparable electrical characteristics may be required. This so-called matching describes the measured adjustment of the tubes to one another.

Brand: McIntosh.
Tube type: KT88.
Version: Original McIntosh tube with McIntosh logo on the glass envelope.
Design: Beam power tetrode.
Base: Octal base.
Typical heater voltage: 6.3 V.
Typical heater current: 1.6 A.
Total height: 114 mm.
Height from base seating surface: 103 mm.
Diameter: 52 mm.
Weight: approx. 90 g.
Application area: Power stage of tube amplifiers.
Output power: Depending on amplifier circuit, operating voltage, and number of tubes used.

Warranty: The warranty terms in our GTC apply.