Bench data
What actually fails on McIntosh.
1,627 repair records mention McIntosh — the most of any brand in the corpus. Here's what they actually talk about, in counts.
McIntosh is the most-discussed brand in our repair corpus — more records mention it than Pass Labs, PS Audio, or Krell. That's partly the brand's size in the vintage market and partly its reputation: these are the amps people keep for decades and finally bring to a bench.
How we count
- 9,561 repair records in the training corpus: forum repair discussions and bench transcripts, tagged by gear type, symptom, and topic.
- Per-brand counts here are keyword co-occurrence across those records — a record counted once per brand and per symptom it mentions.
- These are conversation counts, not diagnoses: they say what people talk about when a brand comes up, not what every unit on earth fails with.
Counts computed from the database, August 2026.
The tubes get the blame; bias takes the fall
Roughly 70% of McIntosh records are tube-tagged — the classic MC tube amps dominate the conversation. But the corpus-wide pattern holds here too: when the fix gets discussed, it's usually bias (140 records), not the tube itself. Output tubes in a push-pull pair drift apart as they age, and an amp that was never re-biased after a tube swap runs hot on one side until something gives.
The practical rule on the bench: if a McIntosh is acting up after a tube change, set the bias before you buy replacement tubes.
The output transformer is the signature — and rarely the failure
McIntosh's hallmark is the output transformer, and it shows: 193 transformer mentions, the highest of any brand in the corpus. Here's the honest part: the transformers almost never die. What ages is everything around them — 109 capacitor mentions, 134 fuse mentions, the power supply that feeds the whole thing. A transformer that smells hot or hums loudly is usually being starved or overloaded by a supply problem upstream.
Hum is a supply story, not a mystery
169 records mention hum with McIntosh. In the repair history the cause is rarely exotic: filter capacitors that have dried out in a 40-year-old supply, a ground reference shared badly between components, or a cable run that picks up the room. The check order that resolves most of it: different outlet, kill coax and Ethernet grounds, then suspect the supply caps.
Before you open it
- Anything with tubes: don't run it without a speaker load, and don't touch the inside — plates carry hundreds of volts.
- Hum? kill the coax and the Ethernet first. Ground loops are the most common false alarm in the database.
- After a tube swap? bias before you buy more tubes.
Not sure what's wrong?
Describe the symptom to the Customer Service Wizard. It's trained on this exact database, plus bench experience, and it will tell you what to expect: likely fixes, effort, and whether it's a bench job.