Hi-Lo Level Converters

Choosing the right hi-lo level converter for your install

A hi-lo level converter, often called an LOC, sits between your factory head unit and an aftermarket amplifier. It drops the speaker-level output down to a clean RCA-grade signal that the amp can accept. The right converter for your build depends on three things: how many channels you need to feed, whether your OEM head unit uses balanced or unbalanced outputs, and whether you need automatic remote turn-on triggering from the factory side.

Two-channel vs four-channel converters

Two-channel converters are ideal when you are adding a single mono amp for a subwoofer, or a stereo amp for front speakers only. Four-channel converters suit full-range builds where you want front and rear speaker amplification, or where you need a separate subwoofer feed alongside your main pair. Some four-channel units offer summed sub outputs, which let you blend the rear left and right into a single mono sub signal without losing low-frequency information.

Features to look for in 2026

Modern installs benefit from a few essential features. Adjustable gain matching prevents clipping and lets you align the converter to the amp input sensitivity. Auto remote turn-on uses DC bias or signal sensing to trigger the amp without needing a switched 12V wire from the head unit. Ground-loop isolation cleans up alternator whine. Higher-tier converters often include load resistors that fool BOSE, Harman Kardon, and Bang and Olufsen factory systems into running cleanly with no fault codes.

Brand quality at a glance

• Audison. Italian-engineered high-end converters with a very low noise floor and balanced inputs, ideal for tier-one OEM systems.
• Hertz. Strong all-round performance and excellent value, popular with installers building reliable daily-driver setups.
• Connects2. Budget-friendly two and four-channel options with dependable signal sensing and solid build quality.
• JL Audio. Industry-respected CleanSweep and FiX line for full active OEM integration, with auto-EQ correction.
• Kicker. Compact KISLOC and KQLC converters with adjustable gain and remote turn-on, well suited to bass-only builds.

Compatibility and fitting

• Fascia adapter. Not required for a converter install on its own, but worth fitting if you are also upgrading the head unit.
• ISO harness. Lets you tap factory speaker leads cleanly without cutting into the OEM loom, keeping the install reversible.
• Steering-wheel control adapter. Keeps your factory wheel controls working when adding amplification alongside a head-unit swap.
• Aerial adapter. Only needed when the converter install is paired with a head-unit upgrade that requires a DIN aerial input.

Wiring and installation tips

Always run your RCA cables down the opposite side of the vehicle from the power leads to avoid induced noise. Set the amp gain to minimum before powering on for the first time, then bring it up slowly while watching for clipping. If the converter has an auto turn-on feature, allow a few seconds for the signal sensing to engage. Earth the converter to a clean bare-metal point, not the amp chassis. Where the OEM head unit drives a balanced BTL load, ensure your converter is rated for BTL inputs.

Common questions answered

Do I need a converter if my factory head unit has built-in RCA pre-outs? No, you can run direct from the pre-outs in that case. Will a converter improve sound quality? Yes, when the head unit produces only speaker-level outputs, a good converter eliminates noise and gives you a clean reference signal. Can I use one converter for both subs and speakers? You can, provided you choose a four-channel unit with a summed sub output.

Delivery, returns, and UK support

All converters ship from our Wolverhampton workshop with same-day dispatch on UK orders placed before 3pm. We offer a 30-day return window on unused stock and full manufacturer warranty on every brand we carry. Need fitting advice? Our team has been installing car audio since 1995 and can talk you through gain settings, channel routing, and OEM compatibility for almost any vehicle.

Why buy from Bass Junkies

Since 1995, Bass Junkies has been a trusted UK car audio specialist. From our Wolverhampton workshop we ship quality hi-lo converters from Audison, Hertz, Connects2, JL Audio, and Kicker. Call us on 01902 863 005 for expert fitment guidance or to discuss your build.