the online magazine for bass players

Search Menu

Tech 21 Unveils Private Stock Formula 21 All-Tube Bass Preamp

Tech 21 Private Stock Formula 21 All-Tube Bass Preamp

Tech 21 has unveiled the Private Stock Formula 21, an exclusive vacuum tube bass preamp. The limited edition preamp is hand-built at the company’s U.S. factory and is housed in a solid mahogany cabinet with a cherry finish.

Custom designed by Tech 21 president Andrew Barta, the Formula 21 came as a vision of an all-tube version of the SansAmp Bass Driver. Its all-tube circuitry features four hand-selected 12AX7 tubes. While its 3-Band EQ follows the SansAmp’s concept, its tube design makes it passive and capable of boosting approximately 6dB.

The Character switch controls a proprietary filter that warms up the bass. Presence is the preamp’s only active tone control and can boost the 2.5kHz range up approximately 6dB. The Bright switch gives a broader range of treble and works in conjunction with the Drive knob: increasing the drive makes the bright less active while a lower drive setting makes the bright more pronounced.

Connectivity includes a 1 megOhm input, 1/4-inch output, and a switchable XLR output. The Tech 21 Formula 21 is limited to less than a dozen units, and will be only available directly for $1949. For more info, visit the Tech 21 website.

Tech 21 Private Stock Formula 21 Tube Bass Preamp Specs:

  • All tube circuitry with 12AX7 low noise, hand selected tubes.
  • Solid mahogany cabinet enclosure with a cherry finish.
  • 3-band EQ, Presence, Drive Controls
  • Character Switch
  • Bright Switch
  • 1 megOhm Input
  • 1/4-inch output
  • XLR Output with switchable line/instrument level
  • Ground lift
  • Approx.weight: 12 lbs