Arc Audio Amplifiers and Combos

Posted by Robert Gomez on

APR 5, 2020

Arc Audio Amplifiers

You want them - we've got them.

When the whole world is out of amplifiers, American Hard Bag has you covered with two exciting new offerings.

The KS 125.6 BX2 and the Moto 720 from Arc Audio. Let's discover the differences and which is right for your Harley application.

So you want to upgrade your Harley bagger sound system, but the worldwide backorder of amps and speakers is getting in the way? Don’t worry - we have new amplifier offerings! We’ve teamed up with Arc Audio to offer two amazing, compact, and powerful amplifiers. Not only that, but we made it easy for you to upgrade your entire system by putting together 10 different combos. There’s something for every need and every bike. So let’s get into the features and benefits of the Arc Moto 720 and the Arc KS 125.2 BX2 so you can determine which is right for your application.

ARC KS125.2 BX2

If you’re a lover of deep, ground-thumping bass, this amp is for you. This compact, yet powerful little amp is perfect for those tight spaces and yields seriously deep bass. BX2 has a bass frequency extension technology that provides increased perceived bass frequency response below the low frequency cut off in an audio system. BX2 uses the principle of the missing fundamental, which creates the sensation of low frequencies by generating a carefully calculated series of harmonics designed to simulate the auditory experience in the human ear caused by the missing fundamental pitch. These harmonics extend the perceived frequency response up to 1.5 octaves below the speaker cutoff frequency (f3) without perceived distortion, increased peak power consumption, or peak speaker excursion. This means you can turn that bass up, still hear all the highs and all without causing the speakers to perform outside their physical design limitations.


The KS125.2 decreases power consumption during low-frequency reproduction up to 75% and uses a high-velocity forced induction fan for additional cooling. The ultra compact design allows for installation in most Harley fairings and allows you to retain all of the factory handle bar controls and features.

10 New Combos.
Zero Excuses.


The Arc Moto is slightly larger in size than the KS, but works well in 1998 and newer Road and Street Glides. It’s more powerful and offers more features, so let’s take a look. It delivers an impressive 720 Watts of power across its four output channels and up to 360 Watts when bridged to a single four-ohm speaker.


The new speaker terminal blocks integrated into the amplifier chassis deliver solid and reliable power delivery in even the harshest of conditions. The signal connectors are plug-and-play to the provided RCA signal input dongle that comes with the amplifier. Input level range switches have been added to the front panel to make it easy to switch between high- and low-level inputs. The system is easy to fine-tune once in place in a Harley fairing. Simply remove the machined aluminum top-panel of the amplifier to adjust the sensitivity and crossover. This same panel also prevents water from entering the switches on the top of the amplifier.


Some of the impressive features include:

  • Auto Sense Turn-On Technology
  • Single Side Plug And Play Connection Design
  • Watertight Direct Connect Speaker Terminals
  • Differential Inputs Allow for RCA and Speaker Level Inputs
  • Terminal Blocks Accept 8-AWG Cables for Reliable Performance
  • High Signal To Noise Ratio Without Compromising Power Output
  • Fully Balanced Input Stage Significantly Increases Flexibility
  • Ultra-Low ESR, High Capacity Power Supply Storage capacitors
  • Bridged Mode Auto Detect Turn-On Works With Chip Based OEM Head units
  • Precision Filtering Reduces Interference in Radio Reception

Basically, you’re getting a more powerful, well-rounded sound experience plus environmental protection.

The Specs

Sure, that all sounds good, but the numbers don’t lie. So let’s take a quick look at some of the key differences in specifications.

KS 125.2 Moto 720


1-Channel @ 4 Ohms (Bridged): 250w

2-Channel @ 4 Ohms (Bridged): 360 Watts


5Hz - 20kHz

10Hz - 20kHz

Crossover Range

50Hz - 550Hz

50Hz - 550Hz

Input Sensitivity

170mV - 3.5V

200mV - 3.5V


8.25"(L) x 4.8"(W) x 1.7"(H)

Dimensions 8.125"(L) x 5.43"(W) x 1.8"(H)




Plug and Play?



At the end of the day, it really comes down to sound preference and budget. The KS 125.2 offers deep bass without risk of blowouts and the Moto 720 offers a more powerful, well-rounded sound experience. At $679, the Moto is about $300 more than the KS ($379), but really does offer greater control and flexibility.

When paired with some Diamond or Hertz speakers, you’ve got one hell of a sound system for your Harley bagger. Ready to gift yourself an amazing new sound system? Shop our collection below or give one of of audio experts a call to discuss your specific needs - 888-311-0016. Your Harley deserves the best and we’re here to help.

Shop the Collection of
New Arc Audio Combos

Paired with Diamond, Hertz, or BLAM speakers, there's a combo for every bike and every need.

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