My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Our take on the Helix Blue B TWO

by Buck Pomerantz

Clean lines and solid power

German engineering and craftsmanship combine to create a sleek amplifier that'll make your vehicle come alive with crystal-clear, powerful music. The Helix Blue B TWO 2-channel amplifier puts out 80 watts RMS each to your full-range speakers, or you can switch to bridged mode to power a subwoofer with up to 200 watts RMS.

Made for high quality sound

The Helix Blue B TWO amp starts with a noise-free input stage, then uses proprietary technology to achieve an incredible level of acoustic accuracy. The attention to detail extends down to the superior internal components, specially "surface-mounted" to double-sided, copper-plated circuit boards, all contributing to superb sound quality. A big, heavy wrap-around heatsink dissipates the heat for cool, reliable play.

B TWO features

You'll find the tools you need to shape your sound. The wide range of the high- and low-pass filters allows you to adjust for the best possible performance from different types of speakers. A bass boost will add even more bang, if you want it to.

Amp for a Helix factory upgrade system

The B TWO can also serve as an amp in a Helix Plug and Play factory upgrade system. You can use an EPC5 Easy Plug Cable and a Helix vehicle-specific adapter harness to plug your B TWO directly into your vehicle's stereo to get its input signal, with no wire-cutting or splicing necessary.

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Highlights:

2-channel car amplifier
80 watts RMS x 2 at 4 ohms (120 watts x 2 at 2 ohms)
200 watts RMS x 1 bridged output at 4 ohms (4-ohm stable in bridged mode)
Class A/B design
variable low-pass filter (15-4000 Hz)
variable high-pass filter (40-4000 Hz)
bass boost (0-18 dB at 45 Hz )
speaker-level inputs via 8-pin harness
preamp inputs and outputs
8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
fuse rating: 30A x 1
11-3/16"W x 2"H x 10-1/4"D
warranty: 2 years
Our 60-day money-back guarantee

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Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and specs chart | What’s in the box? | In-depth notes

Features and Specs

Performance
RMS Power Output (Watts x Channels) Loading...	80 x 2
Peak Power Output (Watts x Channels) Loading...	240 x 2
Power at 2 Ohms (Watts x Channels) Loading...	120 x 2
Bridged Power (Watts x Channels) Loading...	200 x 1
Minimum Impedance Bridged Loading...	4
Minimum Impedance Unbridged Loading...	2
Best Frequency Response Loading...	10-30k Hz
THD at Rated RMS Power Loading...	0.03%
Signal to Noise Ratio Loading...	95 dB
Input Voltage Loading...	---
Features
Amplifier Class Loading...	AB
Low-Pass Crossover Frequency Loading...	40-4000 Hz
Low-Pass Slope (dB/octave) Loading...	N/A
High-Pass Crossover Frequency Loading...	15-4000 Hz
High-Pass Slope (dB/octave) Loading...	N/A
Bass Boost Loading...	0-18 dB
Bass Boost Frequency Loading...	45 Hz
Fan Cooled Loading...	No
Fuse Rating Loading...	30
Speaker Level Inputs Loading...	Harness
Preamp Outputs Loading...	1 pair
Width (inches) Loading...	11-3/16
Height (inches) Loading...	2
Depth (inches) Loading...	10-1/4
Parts Warranty Loading...	2 Years
Labor Warranty Loading...	2 Years

Product Research

What's in the box?

Download owner's manual

Two-channel amplifier
One 30 amp ATO fuse (installed)
Four 3/4" Self-tapping screws
8" Speaker-level input harness (Molex plug on one end)
4mm Allen wrench
2mm Allen wrench
Instruction manual (German/ English)

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team — they open the box, verify contents, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Features
Controls
Connections

Features

2-Ohm Stable: In stereo mode the amplifier is stable down to 2-ohms. The 2-ohm output is 120 Watts RMS x 2 channels.

Bridgeable: The B TWO can be bridged to one channel, outputting 200 Watts x 1-channel into 4 ohms.

Protection Circuitry: The B TWO offers four protection circuits: short circuit (or too low an impedance on the outputs), thermal overload, over voltage, and under voltage.

Controls

Crossover: The built-in crossover has a three position switch to select the crossover operation as high-pass, full-range, or low-pass. The high-pass crossover point is continuously variable from 15 Hz to 4 kHz. The low-pass crossover point is continuously variable from 40 Hz to 4 kHz.

Note: When the crossover switch is in the low-pass position, the high-pass frequency dial is also active. Depending on the high-pass frequency setting, this creates either a subsonic filter (useful for any subwoofer and often necessary for ported enclosures) or a band-pass crossover (with a lower limit from 15 Hz to 4 kHz, and an upper limit from 40 Hz to 4 kHz).

Gain: The rotary gain control is continuously variable from 0.2 volts to 6.0 volts to match the source signal.

Bass Boost: The bass boost circuit is centered at 45 Hz and continuously variable from 0 dB to +18 dB.

Connections

Power: The power and ground inputs are set-screw terminals; they will accept bare wire up to 4-gauge (HELIX recommends 8-gauge minimum) and are tightened/loosened with the supplied 4mm Allen wrench.

Remote: The remote turn-on input is a set screw terminal; it will accept bare wire up to 10-gauge and is tightened/loosened with the supplied 2mm Allen wrench.

Speaker Outputs: The speakers connect to two pair of set-screw terminals; they accept bare wire up to 10-gauge and are tightened/loosened with the supplied 2mm Allen wrench.

Line Input: Stereo RCA jacks connect to the output signal from the head unit.

Speaker Level Input: Use the included harness when speaker level inputs are needed, or use the HELIX Easy Plug Cable and vehicle specific adapter harness (both sold separately, see explanation above).

Note: The included speaker level input harness doesn't use the standard aftermarket color codes, and there's no color key in the manual (although the pin positions are labeled on the side of the amp). The colors used are:

Gray: channel 1 negative

Red: channel 1 positive

White: channel 2 negative

Blue: channel 2 positive

Line Output: Stereo RCA output jacks make adding another amplifier easy. The settings on the built-in crossover have no effect on the line outputs.

Fuse: The amp is protected by a single 30-amp ATO-type fuse.