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D4.125 4ch amplifier

The D4.125 – Amazing Power to Size Ratio

September 6, 2022

DD AUDIO is excited to introduce the world to the new D4.125 amplifier 4ch Amplifier. This amplifier improves upon the wildly popular D4.100a. The improvements can easily be summed up in two words: More! Power! 

In many of today’s installs, wattage per square inch is a deciding factor on what amplifier gets the job. For the D4.125, DD’s engineers were able to take the existing D4.100a’s compact chassis, which is only  7” x 4” x 1.7”, and increase the total output by 20%. The D4.125 can cleanly produce 200 watts per channel for a staggering 800 watts of total power.

Beyond its amazing power to size ratio this amp is packed with features not normally seen on amplifiers in this size and price category.

These features include:

  • Bandpass Crossovers
  • Clipping Indicators
  • Input Mode
  • Auto Turn On
  • Set Screw Power Connections
  • Set Screw Speaker Connections
  • Differential RCA Inputs
  • Discrete Outputs 

The D4.125 also has conformal coated internal components and sealed back switches making it perfect for motorcycle, boat, and powersport applications.

As if this amp didn’t have enough going for it, DD also has a line of made for Harley Davidson brackets that allow the D4.125 to cleanly and securely mount into 2014 and up Harley Road Glides and Street Glides.  


  • 4×125 watts @ 4 Ohm
  • 4×200 watts @ 2 Ohm
  • 2×400 watts @ 4 Ohm


  • 7” x 4” x 1.7”
  • 180mm x 104mm x 43mm


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