Tech 21 Private Stock Formula 21 Vacuum Tube Bass Pre-Amp

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This is a super-exclusive opportunity to own a hand-built, all-tube bass pre-amp created by Andrew Barta, founder of Tech 21. A very limited number of these will be available directly from the factory through Tech 21’s Private Stock Division.

The inspiration for this project came about because Andrew was curious how the SansAmp Bass Driver would sound if he made it with tubes. It was an interesting, and challenging, project because certain tasks had to be accomplished in completely different ways.

Striving to capture the functionality and basic nature of the SansAmp Bass Driver, Andrew ended up with a product that is unique on its own with old-school analog, vintage sound.

For bass, in particular, most of the tone traditionally comes from the pre-amp stage of a bass amp.Therefore, you have a lightweight tube-driven pre-amp and the flexibility to choose the power amp and wattage that best suits your needs.

Here’s a rundown of the controls and features:•All tube circuitry with 12AX7 low noise, hand selected tubes.•Solid mahogany cabinet enclosure with a cherry finish.•3-band EQ. Follows the concept of the SansAmp Bass Driver, but being tube-based, they are passive controls --cutting up to approx.6dB.•Presence.This is the only active tone control, in the 2.5kHz range, and is capable of boosting approx.6dB.•Drive. Determines the amount of drive.Gives you a saturated pre-amp tube sound with warm distortion in higher settings.•Character switch. Proprietary formula filter that warms up the bass, giving more bottom and more top end. Disengaged, you get a more neutral, “Jaco-style” sound.•Bright switch. Gives you a broader range of treble and works in conjunction with the Drive control. As you increase Drive, bright becomes less active.With a lower Drive setting, the bright is more pronounced.•1 megOhm Input. For active basses, you can compensate the sensitivity by decreasing the Drive setting to eliminate any unwanted distortion.•1/4-inch output.•XLR Output. Switchable line/instrument level to run direct to mixing console.•Ground lift.•Approx.weight: 18.5 lbs.•Cabinet measures: 19.0”w x 9.75”h x 8.3125”d•Made in U.S.A.

5-year Limited Warranty, 60-Day Limited Warranty on tubes, direct from manufacturer. Product must be registered with Tech 21.
Manufacturer warrants unit to be free from defects in materials and workmanship for a period of five (5) years [60 days for tubes] from the date of purchase to the original purchaser and is not transferable. This warranty does not include damage resulting from accident, misuse, abuse, alteration, or incorrect current or voltage. If unit becomes defective within warranty period, Tech 21 will elect to repair or replace it free of charge. After warranty period expires, manufacturer will repair defective unit for a fee.

We recommend re-tubing every 1-2 years.

We recommend purchasing tubes from Tech 21 as they are hand selected.

Tech 21 will re-tube at no charge for labor, just the cost of the parts (plus any applicable tax and shipping).

Product Specs

Brand New (New)
Tech 21
Private Stock Formula 21 Vacuum Tube Bass Pre-Amp
Bass Heads


About The Seller

Tech 21 NYC
Joined Mar 2016
Clifton, NJ, United States


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This product can be returned within 14 days of receipt.

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Items must be returned in original, as-shipped condition with all original packaging and no signs of use. Buyer assumes responsibility for all return shipping costs unless the item was not received as described.


Buyer receives a full refund in their original payment method less any shipping costs and a 10% restocking fee.

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Tech 21 NYC

Clifton, NJ, United States
Joined: Mar 2016

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