By definition, “streamlining” refers to the process of making something simpler or more efficient. And this certainly appears to be the direction behind the new Streamliner amps, a series of class-D bass amps from Jeff Genzler and his team at Genz Benz. While other amplifiers in the Genz Benz line offer tone-tweaking options like FET and tube preamps, active parametric equalization, and global signal-shaping circuitry, the Streamliner holds true to its name with a simple, user-friendly control configuration and an all-tube, class-A preamp section.
The Streamliner 900 has a very different look than its class-D cousins in the Genz Benz Shuttle series. The chassis is aesthetically pleasing, with extruded aluminum sides that convey a sense of durability. The knobs feel substantial, and their smooth rotation contrasts with the finer movements of Shuttle pots.
What makes the Streamliner so unique lurks within its clean, well-designed interior. Removing the top plate reveals a six-stage, all-tube preamp with three 12AX7 tubes—one for Gain, one for the Bass and Treble controls, and one for the active Mid EQ. Genz Benz also integrated its proprietary Heat Abatement Technology, which effectively— and just as importantly, silently—cools the unit during operation. Another unique feature is the Streamliner’s 3 Dimensional Power Management (3DPM) technology—a limiter that compresses lower frequencies while leaving upper mids and highs untouched. This creates a feel similar to tube compression while protecting the class-D power amp.
The Streamliner’s front panel is simple and straightforward. The 1 MΩ input matches well with high-impedance pickups— whether they’re in a passive electric bass or a pickup-equipped upright. Next to the input and conveniently placed Mute switch, the preamp section has a Gain switch for overdriven tones. Used in conjunction with the Gain and Volume knobs, it enables you to achieve a variety of tones—from clean tube warmth to a nasty snarl.
A first for Genz Benz is the influence of the Bandaxall topology on the Bass and Treble shelving filters. This creates smooth enhancements to the lows and highs without dramatically affecting other frequencies. And continuing with the streamlining philosophy, Genz Benz simplified the midrange EQ by allowing the user to cut or boost within three frequency centers—220 Hz, 600 Hz, and 2.5 kHz. These commonly used frequency points allow you to add some very precisely tuned punch and presence to your tone.
Rounding out the front panel is a Master knob, and an array of LED indicators confirming power delivery (blue), signal peaking (amber), and Protect mode (red). When you turn on the Streamliner, the red LED also indicates that Warm-Up mode is active and allowing the tube preamp to bias and stabilize properly before operation.
The rear panel has common features like dual Neutrik speakON connectors, an effects loop, and a DI. Genz Benz also included an auxiliary input for a CD or MP3 player, a Tuner Out, a Headphones jack that you can use without a speaker load, and a voltage selector for the world traveler.
Wielding the Hammer
My initial impressions of the Streamliner 900 were based on a comparison with its counterpart, the Genz Benz Shuttle 9.0. Setting both amplifiers flat and pairing them individually with a 4x10 cabinet, it was immediately clear these two amps were very different animals. The Streamliner 900 provided a thick tone and solid attack, and with each pull of the strings I could feel the weight of each note. The Shuttle had a more modern sound with clarity and response, but it couldn’t quite match the warmth and heft of the Streamliner. As a sonic weapon, the Shuttle is more like a sword, while the Streamliner is definitely a war hammer.
I used four basses to assess the versatility of the Streamliner 900—a 1964 Fender Jazz bass, a 5-string Music Man StingRay, a Bill Nash P-style with flatwound strings, and a carved German upright with a Fishman BP-100 pickup. I paired the Streamliner with a variety of 4x10, 1x12, and 1x15 cabinet configurations. After setting the Gain and Volume knobs to minimize peaking, I played the basses with the EQ set flat. Then I tested how various adjustments to certain frequencies enhanced the basic sound.
The J bass retained its clear, articulate tone, and soloing on the bridge pickup sounded round and burpy. Boosting the mids at 220 Hz gave the ’64 J’s aging pickups some extra punch. The 3DPM feature was a big benefit when slapping and popping on the StingRay, because it kept the bottom tight and maintained the bright transients of that modern classic bass. The Streamliner also handled the 5-string Music Man’s B string with good definition. I was also impressed with how well the Nash P bass matched with the Streamliner— pairing the amp with a 1x15 cabinet evoked enough old-school tone to bring out my best possible James Jamerson impressions. I was also able to capture the classic P-bass growl by backing off the Bass control and boosting the mids at 600 Hz.
With all the electric basses, I engaged the Gain switch and experimented with varying amounts of overdrive. The switch is useful in adding an edge or a bit of hair to the tone, but the lack of power tubes seemed to keep the Streamliner from completely hitting the mark on classic overdrive sounds.
While I was pleased with how the Streamliner handled electric basses, I was most impressed when I plugged in my upright. Set flat, the amp brought out the wood of the instrument, as well as a tight, low-end punch on every note. And it was simple to temper the highs of the Fishman pickup by cutting the well-voiced Treble EQ. On a recent jazz quintet gig with the Streamliner, some listeners were surprised to learn my bass was amplified— the tone was that pleasing and natural. I have tried numerous amps in search of these qualities, and the Streamliner 900 has quickly joined the group of rigs that fit the bill for me when gigging with an upright bass.
Besides pumping out great tones, the Streamliner delivered an impressive amount of power for its 6 1/2-pound package. Rated at 900 watts at 4 Ω (500 watts at 8 Ω), the Streamliner held its own against volume-happy guitarists and bombastic drummers. It also blended in well with jazz combos and big bands. If you don’t need that much power, check out the Streamliner 600, which uses the same preamp but is rated at 600 watts at 4 Ω (375 watts at 8 Ω).
The Streamliner 900 is a solid option for great tube tone in a small package. Its simplicity and nod to classic bass designs make it a welcome addition to the Genz Benz family. Their engineers have designed a musical EQ that makes it easy to solve tone issues in live performances. While it’s not the lightest or smallest amongst the many class-D amps on the market, the Streamliner makes up for it with its durable chassis and well-built components. So if you’re seeking a versatile, powerful, extremely portable bass head, the Streamliner 900 is well worth checking out.
you seek portability and tube tone that works well with acoustic and electric basses.
you prefer modern tones or only an all-tube amp will do.
Street $999 - Genz Benz - genzbenz.com