Behringer Ultratone K900FX 90W 3-channel Mixing Keyboard Amp


88 out of 100. Incorporating 325+ ratings and reviews.

Street Price: 

Behringer Ultratone K900FX 90W 3-channel Mixing Keyboard Amp

The Ultratone K900FX is another example of Behringer providing an amp with a higher power rating than their competition deliver at the same price level.

This one is a 3-channel amp delivering 90 Watts of power via a 12" woofer and a 1" tweeter.

It also comes with onboard effects and Behringer's FBQ Feedback Protection System which is helpful if you use the amp as a compact PA system or to amplify acoustic guitar.

Key Features:

  • Output Power: 90 Watts.
  • Number of Channels: 3.
  • Inputs: 3 x 1/4", 1 x XLR, 1 x RCA (Stereo).
  • Outputs: 2 x 1/4".
  • Speakers: 1 x 12" Woofer + 1 x 1" tweeter.
  • Tone Control: 5-band EQ.
  • Frequency Response: Not specified.
  • Size: 17.375" x 16.875" x 11.75".
  • Weight: 41.45 lbs.
  • Manufacturer Warranty: 3 years.


A common comment in positive reviews is that this amp sounds clean and crisp, and has good enough volume to satisfy many reviewers. With its three channel design and multiple input/output options, many users consider this to be a great value amplifier.


A small number of people complained that it wasn't loud enough for them but they were part of a small minority of customer reviews. Note the the XLR mic input doesn't have phantom power so you can't use most condenser mics with it, but that's not too much of an issue because most singers use dynamic mics on stage.


If you need to sing through your amp, as well as putting your instruments through it, then this is a good budget personal PA and Keyboard Amp combination.

Although this was previously on our recommended list, there are now more highly rated options available which you can see in our guide to The Best Keyboard Amps.