What to check before buying a used amp: a short checklist

Think the amp looks fine at a glance? Many people miss the small wear that becomes big problems.

What’s going on

Used amps often look solid. They can sound great in a quick demo. But electronics hide faults. Tubes age. Speakers get tired. Cabinets can hide damage. You can avoid a bad buy if you know what to look for.

Why it matters

A bad amp can cost you more than the price tag. You might need speaker repair, tube replacement, or a service visit to fix crackles. Buying smart saves time and money. It also keeps your rig reliable for gigs and practice.

What to check before you buy

Start simple. Plug in and listen. Then work through these checks in order.

• Power up and watch how it starts; listen for loud pops or hums.

• Test every input and channel; move knobs while music plays to hear crackles.

• Try different volumes; listen for rattles, distortion that isn’t musical, or loss of bass.

• Check speaker cones by eye and press gently near the edge; feel for smooth movement without rubbing.

• Inspect tubes (if present) for burn marks or loose fit and ask about age and recent replacements.

• Look inside the cabinet if you can; check wiring, speaker leads, and any signs of water damage or hot spots.

• Run the amp on stand-by (if it has one) and watch for weird heat or smells.

Micro-moment

You meet a seller in a parking lot and plug your guitar in. The amp sounds fine for a minute, then starts to hiss when you turn a knob. Ask the seller to change channels or try another guitar and cable. Small tests like this expose loose pots or failing tubes fast.

Red flags that should make you pause

If the amp makes a loud pop on startup, walk away unless the seller has proof of recent service. Constant hum or buzz often points to grounding issues or bad input jacks. Uneven speaker motion, visible damage to cones, or a smell of burned electronics are serious problems. Sellers who refuse a demo or who avoid answering questions about history are also a risk.

Simple repair and negotiation levers

If the amp mostly works but has minor issues, use that in your offer. A noisy pot might cost a modest repair. Worn tubes are inexpensive compared with a bad speaker. Ask the seller about recent maintenance and be ready to deduct the likely repair cost from your offer. If a tube amp has original tubes and they are old, ask for a discount or include a promise to replace them before use.

Quick checklist to bring with you

Power cord and fuse condition. All inputs/outputs and footswitch tested. Channels, EQ, and master volume tested at low and high levels. Speaker cone condition and magnet security. Tube glow and fit, or solid-state board condition. Cabinet joints, handles and feet stability. Ask about last service and original receipt.

Bottom line

You don’t need to be an expert to buy a reliable used amp. Follow the checks above and trust what your ears and hands tell you. If something sounds off or the seller dodges test requests, it’s okay to pass. A little time testing now saves headaches later.

Small fixes are normal. Structural problems are not — separate the two before you agree on price.

Today’s takeaway: Test every input and knob, listen for odd noises, and don’t buy if the amp fails basic checks.