PreAmplifier / EQ
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BassXX Preamp for Bass and Guitar

Low-Noise Studio Quality :: Sophisticated Sound
Battery Power Supervision Onboard :: Rugged and Shielded

The BassXX Preamp (pronounced "Bass-ics") is a filter-based pre-amp which provides very flexible parametric EQ control with sweepable mids. Its outstanding sound performance is achieved through careful circuit design with attention to detail and selection of finest components available.
It has an extremely low noise floor and a tube-like dynamic response. The warm and smooth sound has no discernable hiss even at extreme high frequency boosting.
Because the input impedance is higher than most other bass and guitar preamps, passive pickups will retain their natural frequency response and tonal character, as well as piezo ceramic transducers will do.
Pulling 'up' on the treble control achieves true bypass of the EQ and allows for passive operation.
The passive sound is virtually identical to the active sound in tone and level if the EQ is set flat. In passive mode, only the volume controls works, but passive tone control can be added on custom instruments.

The onboard circuit in combination with the battery power supervisory is a patent pending product. When the blue LED starts to flash the battery is getting low and needs to be changed within roughly 10 hours.

All BassXX EQ's/Pre-amps are completely shielded, this means no additional shielding of your instrument control cavity is required.


  • High definition amplifier design results in precise and smooth sound reproduction without signal losses.
  • 0,1% precision metal film resistors in the signal path with a resultant noise factor of up to 10 times lower than standard thick film resistors.
  • Low tolerance film capacitors featuring lowest distortion and superior linearity.
  • Highest quality available trimmer pots.
  • Completely shielded and encapsulated - no shielding inside the instrument is required.

After manufacture each unit undergoes a throughout test and inspection. This ensures each unit passes strictly quality standards. Serial number is carried out for traceability purposes.
Installation of the preamp will require some basic soldering skills. Instead of not being difficult, professional installation is recommended.
NOTE: Excessive heat and incorrect soldering equipment usage or selection may damage the electronics.

Available BassXX Preamp versions:

  • 3BP : 3-Band Preamp with parametric mid control
  • 3B : 3-Band Preamp with fixed mid frequency at 600Hz
    (other freq. upon request)
  • 2B : 2-Band Preamp

Technical Data:

  • Input Impedance : 2,2 MOhm
  • Output Impedance : 47 kOhm
  • Frequency Range : 7 Hz to 22kHz, ±1,5 dB
  • Bass Control : 30 Hz, ±15 dB
  • Mid Control, Parametric : 240 Hz to 1,1 kHz, ±12 dB
  • Treble Control : 6,3 kHz, ±12dB
  • Supply Voltage : 9V battery or accumulator
  • Current Consumption : 1300 µA
  • Weight : 50g
  • Dimensions : L 32 x B 25 x H 24 mm
  • True Bypass
  • Battery Power Supervision via LED
  • Reverse Polarity Protection
  • Fixation through concentric
    potentiometer (bass / treble) with active/passive push-pull switch
  • Parametric Mid Control: Two single potentiometer (frequency/ level) - Optional: One concentric potentiometer
  • Completely shielded and encapsulated - no shielding required inside the instrument