Audio Cable Guide
Hi-fis, soundbars, speakers, headphones and car stereos connect with a few common audio plugs: phono (RCA), 3.5mm and 6.35mm jack, and optical. This guide shows how to tell them apart, which lead to use for the most common jobs, and the adapters and converters that join one type to another.
Phono, jack and optical plugs
| Plug | What it looks like | Found on |
|---|---|---|
| Phono (RCA) | Round plug with a centre pin and a metal collar, usually in colour coded pairs. Phono and RCA are two names for the same plug | Hi-fis, amplifiers, turntables, subwoofers, older TVs and DVD players |
| 3.5mm jack | Thin pin shaped plug, also called a minijack or AUX | Headphones, phones, laptops, tablets, TVs, car stereos and powered speakers |
| 6.35mm (1/4 inch) jack | A larger version of the 3.5mm jack | Studio headphones, guitars, keyboards, mixers and amplifiers |
| 2.5mm jack | A smaller version of the 3.5mm jack | Some older phones, headsets and cameras |
| Optical (Toslink) | Square plug with a small cap on the end; it carries light | TVs, games consoles, TV boxes, soundbars and AV receivers |
- Phono colours: red is the right channel and white or black is the left; yellow is composite video.
- Jack poles: count the thin insulating rings on the plug. One ring is mono, two is stereo, and three is stereo plus a microphone, as on headsets.
- Male and female: a plug is male and a socket is female. An extension lead has a plug at one end and a socket at the other.
Which audio lead do I need?
| Job | What you need |
|---|---|
| Phone, laptop or tablet to a speaker, soundbar or car AUX socket | A 3.5mm jack to jack lead, such as our 3.5mm stereo cable, 1.2m to 10m, or shielded cable, 1.2m to 20m. An angled lead helps where the socket is tight against a wall or dashboard |
| Phone, laptop or TV headphone socket to a hi-fi or amplifier | A 3.5mm jack to phono lead, such as our 3.5mm to 2 RCA cable, 1.2m to 15m, or OFC 3.5mm to phono cable, up to 20m |
| CD player, turntable preamp or other source to an amplifier | A stereo phono lead, such as our twin RCA cable, 1.2m to 10m, or OFC phono cable at 15m and 20m |
| TV, console or TV box to a soundbar or AV receiver | HDMI ARC, or a Toslink optical cable, 1m to 10m; see below |
| Two people listening to one device | A headphone splitter |
| Headphones that will not reach | A 3.5mm extension cable, 0.5m to 10m. For a headset with a microphone, use a 4 pole extension, as a 3 pole lead passes the sound but not the microphone |
| Studio, mixer or keyboard connections | A 6.35mm stereo jack cable, 0.5m to 20m, a 6.35mm to 3.5mm cable, or an XLR cable for microphones |
| Phone to a car stereo with only a cassette player | A cassette adapter |
3.5mm cables3.5mm to phono cablesStereo phono cables3.5mm extension cables
Optical, digital coaxial and converters
- Optical (Toslink) sends digital sound as light, so it picks up no hum. It carries stereo and compressed 5.1 surround (Dolby Digital and DTS). Remove the small caps from the plugs before use and avoid sharp bends. A Toslink joiner joins two cables, and a right angle adapter helps behind a wall mounted TV.
- Digital coaxial carries the same digital sound as optical, on a single phono plug, using a digital coaxial cable, 1.5m to 10m.
- Different sockets at each end: an optical to coaxial converter or coaxial to optical converter.
- Older hi-fi with only phono inputs: an optical to phono converter turns the digital sound into ordinary stereo. Set the TV's digital audio output to PCM or stereo, as these converters cannot decode surround sound.
- HDMI ARC or eARC is the better choice when both the TV and soundbar have it; eARC also carries lossless surround. See our HDMI cable guide.
Optical cablesDigital coaxial cablesDigital audio converters
Speakers and subwoofers
- Subwoofer: a single phono lead from the SUB or LFE output on the AV receiver to the subwoofer, such as our subwoofer cable, 1m to 10m, or our single RCA cable up to 25m. If the subwoofer has two phono inputs, one lead into the input marked LFE, or the left input, is usually all it needs.
- Passive speakers connect to the amplifier with speaker cable, not phono leads. Keep the marked or coloured core to the red terminal at both ends so the speakers work together. Use thicker cable for longer runs, such as our 2 x 1.5mm² OFC cable.
- Flat speaker cable, such as our 2 x 1mm² flat cable, 10m to 50m, is just 2.5mm thick, to run under carpets and along skirting boards.
- 4mm banana plugs make tidy, secure connections on amplifiers and speakers with suitable terminals.
Adapters
- Studio headphones (6.35mm plug) on a phone or laptop: a 1/4 inch plug to 3.5mm socket adapter. The other way round, 3.5mm headphones on an amplifier or keyboard: a 3.5mm plug to 6.35mm socket adapter.
- 2.5mm sockets: a 2.5mm to 3.5mm adapter.
- Plugging a 3.5mm lead into phono sockets: a short 3.5mm socket to 2 phono adapter, which fits the phono inputs on a hi-fi or amplifier.
- Joining leads: a 3.5mm coupler or phono coupler, or a 10m stereo phono extension.
- Tight spaces: a 90 degree phono adapter stops the lead bending sharply behind an amplifier or TV.
Long runs and hum
- 3.5mm and phono connections are unbalanced, so they can pick up hum and interference over longer distances. Keep them as short as you can, and for longer runs choose shielded or OFC cables, such as our 20m 3.5mm cable and 20m twin phono cable.
- Run audio leads away from mains cables where you can, and cross them at right angles rather than side by side.
- Optical and digital coaxial connections are not affected by hum, so they are a good choice for longer runs to an AV receiver or soundbar.
- XLR connections between professional equipment are balanced, which cancels interference, so they suit long runs on stage and in studios.
More cable guides
See also our which cable for my TV? guide for every socket on a TV, and our HDMI cable guide.
Not sure which audio cable you need? Call us on 0207 100 4874 or contact us and we will help.