The Useful Arts BF-700 bass power amplifier is a complete system matching an audiophile-quality Class A tube preamp with a powerful 700-watt Class D power amplifier.
Useful Arts established a new standard for capturing the real sound of the electric bass with the release of its original BF-1 tube instrument preamp/DI and the BF-S studio version. Best known for their exceptional, rich sound quality, the careful design and gig-worthy construction of these products also contributed to their enthusiastic reception amongst top bassists and audio engineers.
Fans of the BF-1 and BF-S cried out for a product with the sound of the BF series plus clean, powerful amplification that could go on a gig or let them record through a speaker cabinet, as well as direct. The BF-700 builds on the legacy of our original products adding more sound-shaping options and plenty of utility functions to make the BF-700 easily fit into any situation.
Starting with the BF Series features
- Ultra-high impedance input to maintain the true sound of the instrument.
- Exclusive impedance conversion method delivers clarity and depth.
- Linear preamp power supply that offers near-noiseless high-voltage tube operation and greater headroom.
- Noise floor better than -70 dBu.Tube-based, two-band EQ. Ear-tuned curves for greatest musicality.
- Standard DI features like a Thru jack, balanced outputs on both XLR and TRS jacks, and a ground-lift switch.
- Robust construction for long product life.
- Rich, full, true sound.
Added features that define the new generation of Useful Arts products
- Finely tuned Color control that adds pure, pentode-generated, second-order harmonics. Fatten your bass sound to taste.
- Effects loop to accommodate your favorite stomp boxes or rack processors.
- Relays in the audio path to avoid signal corruption that can be introduced by passing audio through mechanical front-panel switches.
- Brick-wall high-pass filter at 50 Hz.
- 700 W Class D power amplifier. Plenty loud, delivers clear and pure sound…yet not insanely heavy.
The BF-700 is built for real-world professional use. That means solid construction that stands up to life on the road. It means enough power to connect a speaker cabinet and play a theater gig, plus direct outputs and a Thru jack for feeding sound systems and live or studio recordings. It means a Color control that gives you anything from absolute clarity to a warmer, rounder sound or something sharp and funky. It means you've got a new favorite gigging amp.
Useful Arts BF-700 Class A Preamp/DI and Class D Power Amplifier
700-watt Class D power amplifier
- The amp section delivers 700 watts of clean power for strong, clear sound reproduction.
Tube preamp circuitry
- The preamp stage is all-tube and provides vibrant sound with rich harmonics.
Effect loop: The BF 700 includes an effect loop for inserting serial effects into the signal chain.
EF 86 "color" circuit
- A dedicated color circuit using an EF 86 tube allows for enhanced tonal shaping and character.
Relay-based signal switching
- Mechanical buttons have been replaced with relay-based signal switching for reliable, quiet operation.
2RU rackmount chassis
- The entire unit is housed in a durable 2-rack unit (2RU) enclosure for easy integration into a professional setup.
Input/outputs
- Like the preamp on which it's based, it features a 1/4" instrument input and a balanced XLR output for direct connection to a PA or recording console.
High-quality power supply
- A linear power supply to deliver high clarity, headroom, and a low noise floor.

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