RCA Output: Which Socket Sends What
An amplifier or receiver may have four kinds of RCA output, and connecting to the wrong one is the most common cause of volume problems.
Quick Answer
| Socket | Signal | Feeds | Controlled by volume |
|---|---|---|---|
| Pre out or line out | Line level, fixed or variable | Power amplifiers, powered speakers | Usually yes on pre out |
| Subwoofer out | Line level, filtered | Powered subwoofers | Yes, follows the system |
| Record out | Line level, fixed | Recorders | No, fixed level |
| Zone out | Line level | Second room systems | Independent control |
| Speaker terminals | Speaker level | Passive speakers only | Yes |
Never connect speaker terminals to an RCA input. The level is far too high and can damage the input stage.
Matching Output to Input
Powered speakers
Use pre out or line out. Volume follows the amplifier.
Subwoofer
Use the subwoofer output, which applies the correct filtering.
Recorder
Use record out for a fixed level that does not change with listening volume.
Headphone amplifier
Use pre out if the amplifier controls volume, otherwise a line output with its own volume.
Practical Setup
- Identify the socket by its label, not by position.
- Use a screened RCA cable of sensible length.
- Start with the volume low and raise it.
- Check both channels after connecting.
- If the level is wrong, the socket choice is usually the cause.
Real-World Applications
- Adding a subwoofer to a two channel system.
- Feeding powered monitors from a receiver.
- Recording from a hi fi system.
- Multi room audio distribution.
Related Guides
For subwoofer wiring, read subwoofer RCA cables. For stereo pairs, see RCA to 3.5mm. For speaker level, start with RCA to speaker wire.
FAQ
Why is the volume so low from my RCA output?
You are probably on a fixed level socket such as record out, or the source volume is low.
Can I connect a passive speaker to an RCA output?
No. Passive speakers need a speaker level output from an amplifier.
What is the subwoofer output for?
A powered subwoofer. It applies low pass filtering automatically.
Does record out follow the volume?
No. It stays at a fixed level regardless of the listening volume.