Rolls FX953 Bad Bass Preamp Pedal

$ 149.00

Designed to provide electric guitarists and bassists with a safe and versatile method of exploring the full spectrum of bias shift effects, the FX953 Bad Bass Pedal from Rolls lets you easily under- or over-bias your instrument signals for wild new avenues of sonic potential. With the simple bias control knob, along with independent input and output level controls, you can easily achieve striking changes in sound quality without risk of damage to your circuits from voltage spikes.

The internal Class-A preamp provides up to 43 dBV of gain, helping to maintain usable results even when bias shifts cause massive changes in output levels and distortion/breakup points. Activation is easy with a simple metal footswitch, and you can deactivate the effect without any fear of tone suck or signal loss thanks to the true bypass circuit. For bass guitars, you can replicate the distinctive tonal qualities of different bass cabinets with the 3-way low-pass filter that lets you select 500 Hz, 1 kHz, or 3 kHz. This American-made pedal can either run on the included 15 VDC power supply or a 9V battery (not included).

A New Way to Rebias Your Signals
Born from Rolls' extensive experience in biasing amplifiers and preamps, the FX953 allows you to intentionally over- or under-bias a circuit, delivering striking changes in sound quality. Initially tailored for bass guitar applications, this pedal is compatible with any guitar, making it an invaluable tool for shaping your unique sound. The custom-designed Class-A preamplifier meticulously emulates the characteristics of tube amplification under both over- and under-bias conditions.

Unexpected Outcomes
At its core, this pedal′s primary function is to intentionally manipulate circuit bias, resulting in a desired effect. This manipulation often leads to significant and potentially dramatic changes in sound level and distortion, typically enhancing the overall sound.
However, the bias manipulation can be extreme, causing the signal to shift to one extreme and nearly disappear. This intentional design allows users to explore the full spectrum of bias shift effects. Please be aware that using this pedal can yield a wide range of outcomes, some highly favorable and others that may be considered bad. Hence the name: Bad Bass Preamp.

Box Contains

    Rolls FX953 Bad Bass Preamp Pedal
  • 1 x 15 VDC Power Supply

Returns Policy

You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Easy 30 Day Return Policy

If you are dissatisfied with your purchase for any reason, you may return it to Kellards within 30 days of the purchase date, subject to the conditions and exclusions below.

You may initiate a return or exchange by requesting an RMA at

Securely affix your return label to the outside of the shipping package. Return shipping fees are the responsibility of the customer. We recommend you ship via insured ground service with a tracking number. We cannot be responsible for lost packages.

Return Address

Kellards Return
3237 Greenpoint Ave.
Long Island City NY 11101

Eligibility Conditions

Please read conditions below. If all conditions are not met, Kellards reserves the right to refuse the return or to charge a minimum 15% restocking fee. All returned items must be in new condition, in their original unaltered box (including an intact UPC code) and must include all packing material, blank warranty cards, manuals and accessories. Kellards can only refund the original purchase price. Shipping and handling fees are nonrefundable.

Nonreturnable Items

  • Electronic software downloads
  • Opened consumable items (e.g., film, tapes, paper, bulbs, CD, DVDs, ink cartridges, etc.)
  • Underwater equipment that has been submerged

Defective or Damaged Items

Defective items may be repaired, exchanged or refunded at our discretion for the same model or manufacturer's equivalent model.


Please allow 3-5 business days for mail-in exchanges to be processed.

Refunds & Credits

Once we receive and inspect your item(s), we will credit your account. Please allow 5-7 days for a credit to appear on your account. In most cases, we will issue your refund in the same way you made the original purchase.


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