What tubes does the McIntosh MC275 use?

The McIntosh MC275 uses 2× 12AX7 (input / voltage amp), 2× 12AT7 (phase splitter / driver), 4× KT88 (power tubes).

What power tubes does the McIntosh MC275 use?

The McIntosh MC275 runs 4× KT88 in the output stage. Voltage-compatible alternatives include 6550, KT120 (always re-bias before swapping).

Can I swap the 12AX7 tubes in a McIntosh MC275?

Yes — the 12AX7 preamp tubes in the MC275 are user-replaceable and tolerate tube rolling without bias adjustment. Common rolling alternatives: ECC83. Preamp tube changes are the cheapest way to alter the amp's character.

How much power does the McIntosh MC275 produce?

The McIntosh MC275 produces approximately 75 W per channel of hi-fi audio power. Era: 1961–1973 (original) + reissues.

Tube chart · Hi-fi amplifier

Tubes for McIntosh MC275

Era: 1961–1973 (original) + reissuesPower: 75 W per channel

The MC275 is the reference tube power amp of hi-fi — Sidney Corderman's Unity Coupled output stage cross-couples primary and secondary windings, achieving extremely low distortion and a near-flat frequency response. The KT88 power tubes are key; rolling to KT120 increases headroom but changes the tonal balance.

Complete tube line-up

Every socket in the MC275, with stock tubes, direct-swap alternatives, and rolling notes. Tube names link to dedicated specification pages.

Input / voltage amp × 2
12AX712AX7 / ECC83
Alt:ECC83
Phase splitter / driver × 2
12AT712AT7 / ECC81
Alt:ECC81, 12AU7 (driver)
Power tubes × 4
KT88
Alt:6550, KT120
Rectifier (solid-state)
Solid-state (no tube)

Important: bias before you swap

Power tube swaps almost always require rebiasing — running a new quartet of KT88 cold or hot will shorten tube life dramatically and can damage the output transformer. See the biasing guide and the troubleshooting guide before rolling tubes.

Related amplifiers

Dynaco ST-70 / Stereo 70 →