Buying used
How to Check a Used Receiver or Amplifier Before You Buy
A used receiver or amplifier can be one of the best values in hi-fi. It can also be a box of expensive problems. The difference usually shows up within ten minutes of careful testing, if you know what to check.
This guide gives you a step-by-step test you can run in person, the questions to ask when buying online, and a clear sense of which faults are cheap fixes and which mean walking away.
What to bring to an in-person test
- A pair of small passive speakers you do not mind risking, plus speaker wire. Avoid testing an unknown amp on your best speakers.
- A phone or portable player and a cable to connect it: 3.5 mm to RCA is the most useful.
- Headphones with a 1/4-inch adapter, if the unit has a headphone jack.
- A small flashlight for looking through vents.
- Music you know well, with clear left and right channel content, plus something with deep bass.
- If you own a turntable, a short phono test is worth arranging, or bring a phone app that outputs a test tone through a line input.
Step 1: Visual inspection before power-on
- Cabinet and faceplate. Dents and scratches are cosmetic. A bent chassis suggests it was dropped, which can crack circuit boards or solder joints.
- Back panel. Look for missing or broken RCA jacks, stripped speaker terminals, and a damaged or spliced power cord.
- Through the vents. With a flashlight, look for scorch marks, melted plastic, bulging or leaking capacitors, or heavy dust buildup. Heavy dust often means a unit has been stored rather than used.
- Screws. Chewed or mismatched screws on the case suggest it has been opened. That is not bad in itself, but ask what was done.
- Smell. A sharp burnt smell from the vents is a warning sign.
Safety: do not open the case on a unit that has been plugged in recently. Large power supply capacitors can hold a dangerous charge. Leave internal inspection to a qualified technician.
Step 2: Power-on behavior
Set the volume to minimum, connect your test speakers, and power on.
- Relay click. Many amplifiers and receivers have a protection relay that clicks a few seconds after power-on, connecting the speakers once the circuit settles. A click is normal and reassuring. Repeated clicking, or a relay that never engages, is not.
- Protection indicator. If the unit shows a protect message or light and shuts off, or refuses to pass sound, there is a fault. Disconnect speakers and try again once; if it repeats, treat it as needing repair.
- Display and lamps. Dim or dead display segments and burned-out dial lamps are common on older gear. They are usually cosmetic, but factor the fix into the price.
- Idle noise. With volume low and no music, put your ear near each speaker. A faint hiss is normal. A loud hum or buzz, especially from both channels, can point to power supply problems.
Step 3: Listening and control tests
- Play music at low volume. Confirm sound from both speakers, then use the balance control to pan fully left and right. Each channel should play cleanly on its own.
- Turn the volume up gradually to a moderately loud level. Listen for distortion that appears in only one channel or crackling as the knob moves.
- Rotate every control slowly while music plays: volume, balance, bass, treble, loudness, input selector. Scratchy noise or dropouts mean dirty controls. Usually fixable with cleaning, but it signals the unit has not been serviced.
- Test every input you plan to use. Move your source cable from input to input. Check the tape monitor button on vintage units, because a stuck tape monitor will silence everything.
- Test speaker outputs A and B if present.
- Try the headphone jack. It often reveals channel imbalance clearly.
- Test digital, HDMI and network features on modern receivers: HDMI switching, the TV audio return channel, Bluetooth pairing, the app, and any streaming services you need.
- Let it play for 15 to 20 minutes if the seller allows. Some faults only show up once the unit warms up, such as a channel dropping out or protection tripping.
Which faults matter: a quick triage table
| Symptom | Likely cause | How serious |
|---|---|---|
| Crackle when turning knobs or switches | Dirty or oxidized controls | Usually minor; cleaning often fixes it |
| One channel cuts in and out | Dirty switch or relay contacts, or a bad solder joint | Often repairable; get a lower price |
| Dead dial lamps or dim display | Burned-out bulbs or aging display | Cosmetic; replacement parts vary in availability |
| Loud hum from both channels | Power supply issue, often aging filter capacitors | Needs a technician |
| Distortion in one channel only | Output stage or driver fault | Potentially costly |
| Protection mode that will not clear | Fault detected in the amp circuit | Serious; avoid unless sold as a repair project |
| Smoke or burning smell | Component failure | Walk away |
| HDMI board dead on a modern AVR | Known weak point on some models | Often uneconomical to repair |
Repair costs vary widely by region and technician, so get a quote from a local shop before assuming a fault is cheap to fix.
What to ask the seller
- How long have you owned it, and how was it used?
- Has it ever been serviced, repaired or recapped? Who did the work, and is there a receipt or parts list?
- Do all inputs, both channels, the tuner and the headphone jack work?
- Any crackle, hum, or channels dropping out?
- Has it been stored in a garage, attic or basement? Damp and temperature swings are hard on electronics.
- Is the remote included? Original manual?
- For online sales: can you send a video of it playing through speakers, with each control turned and each input switched?
- What is your return policy if it arrives not working?
Read the listing language carefully. "Powers on" is not "tested and working." "Sold as is" means you carry the risk. "Serviced" can mean anything from a dusting to a full restoration, so ask exactly what was done.
Buying online safely
When you cannot test in person, the platform's buyer protection and the seller's description become your safety net. Favor listings with clear photos of the back panel, the inside if serviced, and the unit powered on. Check that the description explicitly says it was tested with speakers and that both channels work. Packing matters too: heavy amplifiers can be damaged in shipping if poorly boxed, so ask how it will be packed.
When it arrives, test it right away using the steps above so you are within any return window.
FAQ
Is it safe to buy a used amplifier?
Generally yes, if you test it properly or buy with a solid return policy. Amplifiers and receivers are durable, and many faults are visible within minutes of testing with speakers and music.
What does a clicking sound at power-on mean?
A single click a few seconds after power-on is usually the protection relay connecting the speakers, which is normal. Repeated clicking or a relay that never engages points to a fault.
Why does my used receiver crackle when I turn the volume?
Usually dirty or oxidized controls. Cleaning with an appropriate contact cleaner, ideally by a technician, often fixes it. Persistent crackle after cleaning may mean the control needs replacing.
Should I buy a used AV receiver?
It can be good value, but older units may lack current HDMI and audio format support, and HDMI boards are a known failure point on some models. Test every HDMI input and feature you need.
What does sold as is mean for audio equipment?
It means the seller makes no promises about function and returns are unlikely. Price it as a possible repair project unless you can test it first.
The bottom line
A careful ten-to-twenty-minute test catches most problems with a used receiver or amp: inspect it, listen to both channels, turn every control, try every input and let it warm up. Ask direct questions, get service history in writing where possible, and price minor faults like dirty controls or dead lamps into your offer. Walk away from protection faults, burning smells and loud hum unless you are deliberately buying a repair project.