Connecting your turntable to an audio interface requires a crucial intermediate step: a phono preamp. You connect the outputs of the turntable to your phono preamp, then connect the Master Out, Record Out or Line out on the preamp to a pair of inputs on an audio interface. Additionally, be sure to connect the ground wire of the turntable to an earthing screw, otherwise you will get a hum.
Why a Phono Preamp is Essential
A turntable's output signal is very low (mic level) and requires two specific things that a standard line input on an audio interface cannot provide:
- RIAA Equalization: Vinyl records are cut with a specific EQ curve (RIAA equalization) that boosts high frequencies and cuts low frequencies. A phono preamp reverses this curve, bringing the audio back to a flat, accurate representation. Without it, your audio will sound tinny and lack bass.
- Signal Amplification: The signal from a turntable cartridge is very weak. A phono preamp boosts this signal to a standard "line level," which your audio interface is designed to receive.
Step-by-Step Connection Guide
Follow these detailed steps to properly connect your turntable to your audio interface:
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Connect Turntable to Phono Preamp:
- Locate the RCA outputs (usually red and white) on your turntable.
- Connect these RCA cables to the corresponding input jacks on your phono preamp, typically labeled "Phono In" or "Turntable."
- Important: Ensure the red cable goes to the right input and the white (or black) cable goes to the left input.
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Connect Ground Wire:
- Identify the thin ground wire extending from your turntable (it's often a single wire with a U-shaped spade connector).
- Connect this ground wire to the earthing screw (also known as a ground terminal) on your phono preamp. This screw is specifically designed to minimize hum and buzzing noises by providing a common ground for the electrical circuit. If your preamp lacks a ground screw, some interfaces or mixers might have one, but a preamp is the most common place.
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Connect Phono Preamp to Audio Interface:
- Locate the output jacks on your phono preamp. These are commonly labeled as "Line Out," "Master Out," or "Record Out." They will usually be RCA (red and white) or sometimes 1/4-inch (TRS/TS) jacks.
- Connect these outputs to a pair of line-level inputs on your audio interface.
- If your preamp has RCA outputs, you may need RCA-to-1/4" TS cables or RCA-to-XLR cables, depending on your interface's input types.
- Choose two line-level inputs (e.g., Input 1 and Input 2) on your interface, avoiding inputs designed for microphones (unless they have a dedicated line/instrument switch).
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Configure Audio Interface Software:
- Open your Digital Audio Workstation (DAW) or audio interface control panel on your computer.
- Select the inputs connected to your phono preamp (e.g., Input 1 and Input 2) as your recording source.
- Adjust the gain levels on your audio interface to ensure a healthy signal without clipping. Start low and gradually increase until you see a good signal level on your meters (aim for peaks around -6dB to -3dB).
Grounding Your Turntable: A Hum Eliminator
As the reference states, proper grounding is critical. Without connecting the ground wire, you will almost certainly experience an annoying low-frequency hum or buzzing sound in your audio. This hum is often caused by ground loops or electrical interference, and the ground wire provides a safe path for stray electrical noise to dissipate, ensuring a clean signal.
Connection Summary Table
| Device | Connection Point | Cable Type | Purpose |
|---|---|---|---|
| Turntable | RCA Outputs | RCA to RCA | Sends raw signal to preamp |
| Turntable | Ground Wire | Ground Wire | Connects to earthing screw to prevent hum |
| Phono Preamp | RCA Inputs | RCA to RCA | Receives and amplifies turntable signal |
| Phono Preamp | Earthing Screw | Ground Wire | Receives turntable ground wire |
| Phono Preamp | Master Out/Line Out | RCA-to-1/4" TS or RCA-to-XLR | Sends line-level signal to audio interface |
| Audio Interface | Line-Level Inputs | 1/4" TS or XLR | Receives and digitizes the audio signal |
By following these steps, you can successfully connect your turntable to your audio interface, allowing you to digitize your vinyl collection or integrate it into your music production setup with optimal sound quality.
