RCA Cables: Signal Types & Selection Guide – Douglas Bruce

We hear it often: twisted RCAs are best, but this is not accurate. Some claim RCA cables do not matter; let’s examine why they do.

Amplifier Input Types

Amplifiers generally use two primary input types, each requiring a specific cable configuration:

● Single-Ended RCA: The center conductor carries the signal while the outer shield serves as the return/ground. Single-ended RCA setups use a coaxial-style cable.

● Differential Inputs: Both the center and the shield may be sensed as active signal conductors. Differential inputs require a twisted pair cable.

Impact of Cable Mismatching

Swapping or crisscrossing cable types will certainly raise the noise floor, worsen the signal-to-noise ratio (SNR), and degrade frequency response—causing high or low roll-off or even static.

How to Choose the Right RCA Wire for Your System

To get top performance and maximum sound quality from your new US Amps amplifier, you need to determine which input type your equipment uses.

Multimeter Testing Procedure

1. Set your multimeter to measure resistance (Ohms/Continuity).

2. Connect the battery ground lead to the RCA shield (outer ring) on the amplifier.

3. Test for conductivity.

Multimeter Reading	Input Classification	Recommended Cable Type
Ground or 1000 ohms or less	Single-Ended	Coaxial-style RCA
Lacks ground connection	Differential	Twisted Pair RCA

Lacks ground connection Differential Twisted Pair RCA

You should also test the head unit and any DSPs in the system to ensure matching RCAs across the entire audio path. Once complete, you will gain every bit of sound quality from your new US Amps products.