Common Phono Stage Mistakes to Avoid

Most problems with vinyl playback come from a small set of predictable errors — wrong cartridge matching, incorrect setup, and neglected maintenance. Many of them are made at the point of purchase or first setup. Here are the common mistakes to avoid with a phono stage and the correct approach in each case.

Mistake 1: Mismatching MM and MC

Using an MC cartridge with an MM-only phono stage, or vice versa, is the most common purchase error. An MM cartridge connected to an MC input produces an overloaded signal with distortion. An MC cartridge connected to an MM input produces a signal that is too quiet to be useful. Before buying, check the cartridge's output voltage in its specifications. Above 1mV means MM; below 1mV means MC. Some units support both — these give the most flexibility if you plan to try different cartridges.

Mistake 2: Ignoring Input Impedance for MC

Moving coil cartridges are sensitive to input impedance. The standard 47k ohm loading is appropriate for MM cartridges but often produces an overly bright, ringing sound with MC types. Many MC-capable units allow the input impedance to be adjusted — check the manufacturer's documentation and the cartridge specifications. The recommended loading for the cartridge is usually between 100 and 1000 ohms depending on the model. This adjustment is frequently overlooked but makes a significant difference to sound quality and correct phono stage performance.

Mistake 3: Grounding Hum

A constant low-frequency hum from the speakers is usually a ground loop problem. This is common when a turntable is connected without its earth wire, or when the earth wire is connected to the wrong point. Most turntables with a separate earth wire should have it connected to the earth terminal on the phono stage. If hum persists, check that the earth wire is making good contact at both the turntable and the unit. Poor contact at either end is a frequent cause of hum that looks correctly connected but is not.

Mistake 4: Double-Amplifying the Phono Stage Signal

Turntables with a built-in preamplifier have a switch to enable or disable it. If you connect such a turntable to a phono input with the turntable's built-in stage switched on, the signal is amplified twice — producing distortion and an overloaded signal. Disable the turntable's built-in stage if connecting to a dedicated phono input, or enable it if connecting to a line-level input. Check the turntable's documentation to confirm the switch position. For a full setup overview, see our complete guide.

Frequently Asked Questions