Skip Navigation

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 FOUR 4-channel amplifier puts out 60 watts RMS each to your full-range speakers, both front and rear. Or, you can use the B FOUR in 2-channel mode to power a couple of subwoofers with up to 180 watts RMS each.

Made for high quality sound

The Helix Blue B FOUR 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 FOUR 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 FOUR 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 FOUR directly into your vehicle's stereo to get its input signal, with no wire-cutting or splicing necessary.

Product Highlights:

  • 4-channel car amplifier
  • 60 watts RMS x 4 at 4 ohms (90 watts x 4 at 2 ohms)
  • 180 watts RMS x 2 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: 25A x 2
  • 14-1/4"W x 2"H x 10-1/4"D
  • warranty: 2 years
  • Our 60-day money-back guarantee

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.

Helix Blue B FOUR Reviews

Average Customer Review:

3 Reviews

Love it.

Written by: Bullitt from Houston, TX on April 6, 2014

Crutchfield Customer Review (What's this?)

Amp seems to be a great valve. Excellent performance for a medium priced amp. Output seem to be better than the rated wattage. VERY clean. You are also able to do a band-pass crossover - High Pass crossover combination which allows me to bi-amp my component speakers without a crossover. No other amp in this price range can do this.

Pros: Great sound, Great flexibility due to better than average feature set. Better sound than my JL Audio Slash series amp I replaced.

Cons: It wasn't free.

Solid amp all the way through

Written by: Nate from Leesport, PA on June 14, 2013

Got this amplifier for a good price somewhere, but anyway this amp is an extremely solid aluminum frame with heatsink fins that go out 1/4" to 3/8" and offer better cooling than other amps of equal power handling I am currently running 2.7 ohm polk mobile monitor 5x7's to this on every channel and it barely gets warm, so I'd assume this would stay even mildly warm even on a hot summer day on a 2 ohm load The sound quality is phenomenal but even with hearing it and tuning it by hand sounds good if you can, BUY THIS AMP, it's one of the best of the best for this good price range other than the helix esprit tube amplifier, but that runs double

useful features: the active crossovers are amazing and allow for an assortment of functionality to this amp whether you plan on running tweeters, mid range or subs on this amp it'll do it to its best for tweeters it can cut off up to 4khz of signal to give the passive crossovers on back of speaker less work for dedicated mid drivers, you can turn on the low pass filter and and cut off the highs up to your desired frequency and the high pass will remain on to cut off the extreme lows as a band-pass filter and allow your midrange to only the intended range for subs, it can do the same with the low and high pass and the high pass will protect your subs from overexerting when in a ported box as you could put it down to 15-25 hz and cut off the low lows and each channel has a 0-18 db 45 hz bass-boost for each channel

Pros: Through hole terminals go at an angle to grip the wire better than average amps, solid cooling

Cons: A bit hard to get screws through mounting holes because of aluminum fins, but cutting the fins would ruin the aesthetics of the amp

Helix blue B4--awesome amp

Written by: JJ from New Jersey on November 15, 2012

Crutchfield Customer Review (What's this?)

Great amp! It really is very quiet -- I get no alternator noise through this amp at all. I love the fact that this amp is German made and engineered.



Hands-on research

What's in the box?

Download owner's manual

  • Four-channel amplifier
  • Two 25 amp ATO fuses (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)

Product Research



2-Ohm Stable: In stereo mode (powering four speakers) the amplifier is stable down to 2-ohms. The 2-ohm output is 90 Watts RMS x 4 channels.

Bridgeable: The B FOUR can be bridged to two channels, outputting 180 Watts x 2-channels into 4 ohms. You can also wire the B FOUR in three channel mode, bridging half the amp and running the other half in stereo (60 Watts RMS x 2 channels plus 180 Watts x 1-channel).

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


4-Channel: The amplifier is divided into two sections, channels 1/2 and channels 3/4. Each pair of channels has independent gain, bass boost, and crossover controls.

Crossover: The built-in crossovers have three position switches to select the crossover operation as high-pass, full-range, or low-pass. The high-pass crossover points are continuously variable from 15 Hz to 4 kHz. The low-pass crossover points are continuously variable from 40 Hz to 4 kHz.

Note: When a 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 controls are continuously variable from 0.2 volts to 6.0 volts to match the source signal.

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


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 four 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: Two pair of 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:
  • Black: channel 1 negative
  • Yellow: channel 1 positive
  • Gray: channel 2 negative
  • Red: channel 2 positive
  • White: channel 3 negative
  • Blue: channel 3 positive
  • Green: channel 4 negative
  • Orange: channel 4 positive

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

Fuse: The amp is protected by two 25-amp ATO-type fuses.

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 verify what’s in the box, 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.

Customer Q&A

1 question already asked

The amp is made in Germany [ HAMID  Nov 16, 2014 ]