Bench data
What vintage audio actually fails.
Seventeen thousand repair records, one honest answer. No forum hearsay, just counts.
We've spent the last year building something unusual: a database of more than 17,000 real repair discussions, bench records, and support transcripts. It started as the training set for our diagnostic tools. Somewhere along the way it became the largest view most people will ever get of how vintage audio gear actually dies.
This is the first public pass over that data. No forum hearsay, no "my buddy's tech said." Just counts.
How we count
- 13,700+ forum repair discussions crawled from eight audio communities: Audiogon, PS Audio, DIYAudio, GroupDIY, ASR, WBF, AudioShark, and AudioCircle.
- 3,600+ transcripts of bench discussions and repair history.
- More than 7,100 structured training records extracted from the above, each tagged by gear type, symptom, and topic.
Data as of August 2026, pulled from the database before publication.
A caveat before the numbers: the corpus skews toward amplifiers and preamps, which dominate forum repair talk, and toward PS Audio power components, where a chunk of the bench history comes from. These are the failures audiophiles talk about and bring to a bench, not a random sample of everything ever built. With that said, the patterns are loud and consistent.
Hum and buzz is the most-reported symptom
More than 1,300 records carry the hum tag, roughly one in five of everything we've tagged. Nothing else comes close. Buzz, hiss, and crackle add a few hundred more.
The interesting part is the cause. In the data, hum is rarely the thing that failed. It's the signal of something else: a ground loop between components, a failing power supply, a cable run that picks up the room. Class D amps feeding subwoofers show up over and over with a hum that persists even with the system off, because the sub's ground reference fights the amp's.
Check order that resolves most of it: different grounded outlet, kill the cable TV ground (coax is a notorious hum carrier), unplug Ethernet, then suspect the supply caps.
The power supply is where gear goes to die
Tag the records by component and one answer keeps coming back: the power supply. More than 1,400 records are tagged psu, capacitors show up in over 400, fuses in dozens more. Pair that with the bench history and the picture is clear: electrolytic capacitors dry out, bulge, and leak with age. On a 40-year-old receiver it's not a question of if, it's when.
This is why a recap is the single most common job on our bench. Not because it's the fun answer, because it's the true one. A full recap starts with the power supply, and it fixes hum, crackle, weak bass, and half a dozen symptoms that look unrelated at first.
Tube amps dominate repair conversation
Nearly 4,000 records are tagged tube, more than half of the corpus. The same few output tubes keep appearing: 6L6, EL34, KT88, 300B, and the 5AR4/GZ34 rectifier, which is often the first tube to fail.
Here's what the data says about tubes specifically: the tube is usually not the problem. Bias drift is tagged in more than 450 records, and red-plating comes up whenever bias is ignored. Every time you swap output tubes in a class A/B amp, the bias needs to be set. Gear that never gets biased drifts until something gives, and the failure gets blamed on a tube that was fine.
Speakers fail by age, not by accident
Speakers show up in more than 2,500 records, and their failures are the most predictable of all:
- Foam surrounds rot. Every speaker over ten years old will eventually need a re-foam. Not patch, replace.
- Crossover capacitors drift. The original electrolytics in a crossover can drift 20 to 50 percent off value. Replace with film caps of the same value and the speaker sounds like new, sometimes better.
- Ferrofluid dries up in dome tweeters, making them sound dull long before they die.
Turntables fail in two places
Turntables show up in more than 2,300 records, and the failures cluster hard. Nine times out of ten, a speed problem is the motor capacitor, a wax-and-paper part that dried out decades ago. And turntable hum is almost always the ground wire from the tonearm base, broken or disconnected, with the cartridge ground strap second.
The pattern behind the numbers
Strip away the brand names and the model numbers and the data tells one story: vintage audio fails by age, not by accident, and capacitors are the universal first suspect. Amplifiers, power supplies, crossovers, turntable motors. The part is different, the failure is the same.
That's good news, and it's the point of this whole database. A 1972 receiver that "just died" is rarely dead. It has a tired power supply and forty years of dried-out capacitors. Those are fixable, often with parts that cost less than a nice dinner. The gear was built to be repaired, and right to repair starts with knowing what to look for.
What to check before you send anything to a bench
- Hum? Kill the coax and the Ethernet first. Ground loops are the most common false alarm in the entire database.
- No power? Check the outlet, the cord, the fuse. Then stop. The caps are the next suspects and they hold charge.
- Speed wrong on a turntable? Motor capacitor. Replacing it is cheap.
- One channel dead? Dirty switches and pots cause more false alarms than failed output stages.
- Anything with tubes? Don't run it without a speaker load, and don't touch the inside. Plates carry hundreds of volts.
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.