Demeter HBP1-800D Powered W/O Jensen

A Versatile Solution for Bass Amplification

The HBP-1-800D H Series Tube Bass Pre/Power amplifier by James Demeter integrates an 800 Watt Class D amplifier, driven by Jensen Transformers, into the HBP-1 Preamplifier circuit. This unit uses the same all tube front end found in his classic VTBP-201 Bass pre-amplifier and combines it with the revolutionary H Series circuitry found in his professional audio H Series line. Utilizing the best of both the tube and solid state world, the HBP-1-800D features high voltage (250V) tube front end (providing all of the preamplifier gain and passive tone controls), a two band solid state fully parametric equalizer that is tuned for bass, a fully adjustable active effects loop with controls up front, a tuner output, a full balanced output with switchable mic or line level, both a balanced TRS line level output and an unbalanced line level output for amplifier connections and a mute switch.

Our pre/power amp circuit is unlike any other. Using Jensen transformers, we have achieved complete isolation between our pre & power amp section. This allows for noiseless operation, whether you use the preamp on it’s own, or in tandem with the power amp output. Our transformer based design also has the unique advantage of ‘warming’ up the power amp output.

The power amp section also features a Speakon and 1/4” speaker output. As with all Demeter equipment, it is meticulously hand-wired using the finest components and assembled in the U.S.A.

Preamp Specifications

• Input impedance: > 1megohm

• Minimum load impedance: 600ohms

• Ouput Impedence (studio output): 50ohms, balanced
  • HBP1J: 150ohms (balanced)

• Maximum output: + 24dBV @ 600ohms

• Gain: Adjustable to + 10dB Mid 440Hz to 4KHz

• EQ gain : + or – 15dB

• Signal to noise ratio: – 80dB

• THD : .5%

• Frequency response : 10Hz to 40kHz

• Tube: 1-12AX7a selected

• Parametric EQ: Q or width continuously variable Low 40Hz to 440Hz Mid 440Hz to 4.4KHz

• Inputs: 1/4″ (passive and active)

• Outputs (preamp): 3-pin balanced mic/line, TT, XLR & ¼”

  • HBP1J (preamp): 3-pin balanced mic, with switchable post/pre eq

• Chassis: Single space rack

• Operating voltage: 115V/230V AC switchable

• Power supply: 250V fully regulated

• Filament: 12.6V fully regulated

Power Amp Specifications

• Outputs (power amp): 1/4” Speaker & Speakon

• Output impedance (power amp): 4 ohm, 8 ohm, 16 ohm

• Output Power (power amp): 800 watt RMS @ 4 ohms, 500 watt RMS @ 8 ohms