Hands-On Review:The Genz Benz Streamliner 900 Bass Head

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A lightweight yet mighty tube bass amp

By Tom Foster
Harmony Central Contributor

The Genz Benz Streamliner 900 Bass Amplifier Head

Like many bass players I struggle with the age-old question: Should I use solid state or tube amps? While I like the convenience and lighter weight of solid state amps, I find I still need that warmth you seem to get only with tube amplifiers. Yet the downfall is that many of the top bass tube amplifiers seem to be made of dwarf star material—they are all impossibly heavy for such small objects.


The good news is that Genz Benz—the same company that brought you the very cool and small Shuttle bass amps—has finally solved this "weighty" problem with the Genz Benz Streamliner 900. The Streamliner 900 is a 900-watt marvel, weighing in at less than seven pounds, yet providing a warm, tube-based preamp. I got a chance to look at one of the very first models right off the assembly line, and I have to say I'm impressed—the Streamliner 900 is an ideal amp for the gigging bass guitarist.

Lovely to behold

When you take the Streamliner 900 out of the box, the first thing that hits you is how small it is. Weighing in at 6.5 pounds, the Streamliner is about the size of the two-volume set of the Complete Beatles sheet music—light enough to toss in a gig bag. The sleek, anodized aluminum panels give the Streamliner a sophisticated look, like you'd find with a high-end microphone preamp.


Yet where the Genz Benz Shuttle amps fairly bristled with knobs, the Streamliner 900 has a much more elegant design. According to Genz Benz, the Streamliner was designed for the gigging bass player, where you simply set the controls and leave it for the rest of the night. Along with the traditional volume and tone controls (treble and bass), you'll also find a mute button, gain switch, gain control, and midrange gain and mid-frequency selection controls.


In the back of the Streamliner 900 you'll find an amazing and incredibly useful input and output section. In addition to two Speakon outputs, you'll find an effects loop, headphone output, aux input for MP3 players, a tuner output, and a studio-quality direct output XLR jack to send the signal straight to a PA or powered speaker.

Dialing in the mids

The midrange EQ controls on the Streamliner are a great feature—especially for bass players who often forget that the bass is actually a midrange instrument. This is why some players kill the midrange and boost the bass tone onstage, effectively turning their bass sound into mush.


The Streamliner 900's midrange control is much more effective, giving you a way to dial-in a tone that is perfect for your style of music. Besides a midrange gain control, the Streamliner 900 gives you three midrange frequencies (220Hz, 600Hz, and 2.5kHz) to give your sound punch without getting lost in the mix. For example, boosting the 2.5kHz midrange position is ideal for getting that John Entwistle tone. Playing funk? Switch the midrange select to 600; dial up the gain; and transform your sound into a tight, punchy funk machine.

Tasty tubes

Adding to all this bass-tone splendor is the Streamliner 900's tube preamp section. Featuring three 12AX7 tubes, the Streamliner 900 contains a pure Class A six-stage preamp. When turned on, the tubes glow behind the transparent blue Genz Benz logo, letting you know that they are up and running. The warmth that the tubes provide to your bass signal is amazing, even when dialing up the gain for a real tube overdrive sound.


Genz Benz has been making tube-based amplifiers for years, and their expertise in creating a durable, roadworthy tube amp really shows. For example, instead of the usual two power switches (On and Standby) that you'd find on most tube amplifiers, the Streamliner 900 has a startup mode that buffers the power to protect the onboard tubes. Hit the On switch, and the Steamliner 900 goes into a warmup mode, coming online a few seconds later—once the tube preamp has properly powered up.

Streamliner in performance

When it comes to performance, the Streamliner is amazing. Genz Benz provided both a Streamliner 900 and an Uber 410 bass cabinet, which I took to a gig  with a friendly but often loud classic rock band. The results were nothing short of amazing—the band couldn't believe that my huge sound came out of this tiny box.


When playing, the Streamliner 900 effortlessly pushed out my Fender Precision Bass into the mix, with both clarity and a warm tube fatness to the sound. The manufacturer uses what they call a 3-Dimensional Power Management technology that carefully limits signal overages while maintaining great dynamics. Like a great tube amp should, the Streamliner 900 responded to my playing, cranking on the grind parts and becoming quiet as a whisper on softer tunes.

A great buy

For the serious gigging bass guitarist, the Streamliner 900 is a dream come true: massive power in a lightweight head that provides total clarity and pure Class A tube warmth. It is with serious regret that I have to give back the Streamliner 900 to Genz Benz—it is simply one of the best bass amp heads that I've seen in a very long time!

Features & Specs

  • Pure Class A 6-stage tube preamp
  • Modified passive Baxandall EQ for highs and lows
  • Active tube-driven mid EQ
  • Selectable 3-position mid frequencies (220Hz, 600Hz, and 2.5kHz)
  • Input mute
  • Hi-gain switch
  • Master volume
  • Full direct output interface
  • Effects loop
  • Headphone jack
  • Aux input
  • Dual Speakon outputs
  • SMPS and Class-D power amp design