If it weren’t for musicians, audiophiles, and the occasional defense contractor, vacuum tubes would have disappeared long ago. In nearly every category save sound, transistors and other solid-state devices make better sense. They’re smaller, more durable, require less power, stay relatively cool, and are available in innumerable forms well designed for nearly any electronic application. Yet, it’s difficult to make a transistor sound like a tube, especially when it’s overdriven into clipping. Back in 1989, though, a New York guitar player-cum-engineer named Andrew Barta got as close as almost anyone. The original Tech 21 SansAmp made such clever use of field-effect transistors (FETs) and frequency shaping that it quickly became a standard piece of gear for guitar players looking to get a tube-y sound without schlepping a tube amp. Later, the SansAmp Bass Driver DI did for us what the original SansAmp did for guitarists, offering the grind, grit, and growl of iconic tube heads in a stompbox. Tech 21’s product line has expanded greatly since the early days, yet it’s never lost touch with the patented technology that endeared the company to thousands of musicians. Tech 21 recently added the VT Bass 500 To its full line-up of effects and amps. While it may look like yet another medium-powered Class D/SMPS lightweight head, its singular heritage separates it from the crowd.
The VT Bass 500’s design is straightforward. The front panel is where all the action takes place, save the power switch and speaker outputs. The amp makes good use of the space available, with each knob and switch clearly labeled. The single q" input does double duty for passive and active basses thanks to its accompanying pad switch. Kudos to Tech 21 for the high-sensitivity setting’s 4.7MΩ input impedance to avoid loading passive basses. The lower sensitivity setting decreases the impedance for better compatibility with preamps and long cable runs. The Tech 21 has an average amount of I/O. Beyond the de rigeur speaker and di out, there’s an effect loop and headphone jack. Unlike many heads, it does not offer a line-level tuner output (which can double as an unbalanced line out) or an auxiliary input for stereo playback. I was also disappointed not to see a mute switch, although Tech 21 says most of its customers use a stage tuner with a built-in mute function.
Beyond the Tech 21’s SansAmp circuit (I’ll get to that shortly), the VT Bass 500’s tone shaping is straightforward and effective. Three bands of well-voiced EQ span the frequency range, with the midrange enjoying a center-frequency shift thanks to the shift button. It quickly altered the amp’s personality, especially when I boosted the mids and played fingerstyle. By far the VT Bass 500’s most compelling feature is its onboard SansAmp. It’s the same circuit as in Tech 21’s Character Series VT Bass DI pedal, and it’s cleverly integrated into the amp. Just like with a tube amp, the drive control governs the amount of distortion in the preamp as well as gain, with settings above about 12 o’clock growing a nice furry pelt. The character knob is a potent frequency shaper, going from foreboding and dark when it’s counter-clockwise to fizzy and focused as it’s turned up.
I tested the VT Bass 500 with the Tech 21 B112-VT 1x12 cabinet (see sidebar) as well as a Barefaced Audio Big Baby II, an Epifani 4x10, and in my studio running Logic through a Metric Halo ULN-8. First, I wanted to check out the amp’s clean sound, since that’s where I spend 90 percent of my playing life. Interestingly, Tech 21 recommends turning the level control all the way up and then using drive for volume when a clean tone is desired. In practice this does not seem like a good system to me, as there’s no way to get silence in this setting. In fact, for me, my biggest initial hurdle with the VT Bass 500 was negotiating the relationship between the drive, blend, character, and level controls to arrive quickly at sounds ranging from crisply clean to dirty. I found it easier eventually to think of the VT Bass 500 more like a tube head, in that its primary gain-governing and frequency-sculpting controls (except the EQ) are highly interactive. The head is capable of a good clean sound, and its power amp seems well up to the task for most gigs, but it’s really a head that’s better suited to those who know they’ll want to avail themselves of the SansAmp circuitry.
And what a circuit it is. The VT Bass 500 has some of the best onboard distortion I’ve heard in an amplifier. Coupled with the character control, its flexibility reveals itself, ably aping subtly growling B-15-style tone and brutal Lemmy-approved buzzsaw grind. The overdrive has a rich and smooth character with a beautiful tube-like texture that brims with harmonics and vibe. Its dynamic sensitivity is also tube-y; digging in and pulling back can greatly impact the resulting sound. I loved being able to fold in the distortion carefully via the blend control, too. It’s so hip that I’d love some kind of external control of the parameter, as it’d be fun to toy with the distortion without having to turn a front-panel knob.
The VT Bass 500 is perhaps the best lightweight head out there for folks who like their tone to have a bit (or a lot) of edge. While I’d probably steer players elsewhere if they want a super-clean and transparent sound, the Tech 21 does a reasonable job of that, too. It’s a potent tool for getting the sound of tube amps that weigh more than ten times as much, and its affordability makes it a fantastic value, given its overdrive utility.
Tech 21 sent along its new B112-VT 1x12 ($500 street) cabinet with the VT Bass 500. The 8Ω cab is rated for 300 watts and also sports a tweeter with accompanying defeat switch. It’s well suited as a standalone for the VT Bass 500, especially with its vibe-y trad look and aggressive midrange. It’s a good size and decent weight, too. Considering the cab was designed in part to pair with the VT Bass 500, it’s not surprising that I was able to coax fantastic tone from the two. Other cabs might offer higher power handling or a few more bells and whistles, but it’s voiced just right for the head.
Tech 21 VT Bass 500
Pros Incredibly flexible and fabulous-sounding overdrive; loud and authoritative for its size and price
Cons Lacking a tuner output and mute switch
Bottom Line For the cost of some high-end distortion stompboxes, the VT Bass 500 is an amp that probably offers better distortion. It can go from warm and furry to brutal and aggressive, and it’s attractively priced.
Power rating 500 watts @ 4Ω minimum load
Power amp topology Class D
Power supply Switchmode Input impedance 4.7MΩ; 10kΩ w/pad engaged
Outputs Two Speakon, xlr balanced line out (w/ground lift), q" send out, q" headphone out
Tone controls bass, ±18dB @ 55Hz; mid, ±18dB @ 500Hz w/shift engaged, 1kHz w/shift disengaged; treble, ±18dB @ 3kHz
Weight 6.5 lbs
Made in Korea