HAO Bass Liner

The HAO Bass Liner is a bass preamp pedal with a 5-band EQ, built into a hand-built, stompbox-sized enclosure¹. HAO, a Japanese boutique pedal company, unveiled it in August 2012, co-designed with Phil Jones of Phil Jones Bass¹. It sits in the same family as a dedicated EQ pedal, but its input gain and level controls let it serve as a full preamp for a bass pedalboard, not just a tone shaper.

The idea behind the pedal is straightforward: give a bass player flexible tone shaping in an easy-to-use package. Premier Guitar described the result as "a 5-band EQ that provides flexible enhancements in an easy-to-use package"². HAO positioned it partly as a way to make a vintage instrument work like an active one without modifying it. As Premier Guitar's reviewer put it:

What it does

The Bass Liner is a preamp and equalizer in one box. Five individual EQ knobs control the frequency spectrum from 50 Hz to 12 kHz, so a player can boost or cut low fundamentals, low mids, high mids, and presence independently³. Each EQ knob offers 18 dB of boost or cut, with a middle detent to prevent coloration². At that center detent, the controls have a flat response and do not change the instrument's unique tone¹, which means the pedal can sit in a chain as a clean preamp and only shape tone when you ask it to.

Because it carries an Input Gain control and a Level control, it can also balance signals. HAO's introduction framed it as a tool to suit any bass, and Premier Guitar noted it can help balance the overall signal of multiple instruments at a gig, useful for a player switching between basses with different output levels¹².

The controls

Each of the five EQ knobs covers its own band with 18 dB of boost or cut available in either direction, and the middle detent marks the flat setting so you can find neutral by feel². The mute footswitch is the other performance control: it cuts the main signal while the secondary Direct Output jack keeps feeding a tuner, so tuning between songs happens silently¹.

Power and connections

The Bass Liner runs on a 9-volt battery or a tip-negative polarity DC adapter between 9 and 18 volts¹. Performer Mag measured power consumption at 45mA on a 9V battery and 52mA at 18V DC³. The voltage choice is not cosmetic: HAO states that the higher the voltage, the more punch and clarity¹, and Performer Mag's reviewer Chris Devine found in practice that "The 18v gives a lot more headroom and is a bit quieter"³.

For connections, the pedal has two outputs: one typical signal out and one direct out³. The direct out is the one intended for a tuner when using the mute switch¹³. Performer Mag listed an input impedance of greater than 20K ohm and an output impedance of greater than 30K ohm, with a frequency response of 10Hz to 120KHz and a signal-to-noise ratio of 82dB³.

Where it came from

HAO introduced the Bass Liner Preamp pedal on August 5, 2012, describing it as hand-built and co-designed with Phil Jones of Phil Jones Bass¹. It launched in the US at $349, distributed by Godlyke¹. Performer Mag's review later that year listed the price as $299³, so the two published figures disagree; both are given here with their dates.

What reviewers said

Published reviewers were positive about the pedal's core jobs. Premier Guitar's review summed up its strengths as "Accurate tone, excellent EQ, and a solid build"². Performer Mag's Chris Devine found it worked across instruments: "Regardless of the pickup type, it sounds great, and even with passive single coils, the sound is rich and full"³. He also confirmed the silent-tuning workflow in use: "Hooking up a tuner to the direct output, and using the mute switch enables silent tuning"³.

Videos

Click to load

Click to load

Click to load

Questions