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K4040 K4040 K4040 K4040 K4040

Level 5: Professional

For most of us a high power tube amplifier is unaffordable. This kit changes that, so that now everybody can enjoy that sublime "tube sound". The sound of tubes has never been surpassed, nor by transistors, nor by FETs. In the course of developing this amplifier, special attention was given to the housing so that the expensive tubes are on display in a way that is very pleasing to the eye. The weakest point of an tube amplifier are the output transformers ; that's the reason why we use ultra-linear and over-rated output transformers (toroidal) to guarantee a rich bass response. To extend the life of the precious valves, the amplifier is provided with an switch on delay, so that the high voltage is switched on when the tubes are warmed up.


  • pure valve sound with high quality EL34 tubes
  • high quality black and chrome housing
  • chrome valve socket covers
  • easy bias adjustment with LED indication
  • removable bottom for easy access and service
  • high quality capacitors and components
  • gold plated input and speaker terminals
  • standby function
  • "Soft start" circuit for power transformer


  • output power: 2 x 90Wrms music power for loads of 4 or 8 ohm
  • power bandwidth: 15Hz - 40kHz (-3dB ref. 50W)
  • frequency range: 8Hz - 80kHz (-3dB ref. 1W)
  • harmonic distortion: 0.08% (1kHz / 1W) / 0.7% (1kHz / 90W)
  • signal-to-noise ratio: > 105dB (A-weighted ref. 90W)
  • channel separation: >75dB (ref. 90W)
  • input impedance: 34Kohm
  • input sensitivity: 1Vrms at 95W
  • damping factor: >10 (100Hz)
  • weight: 23.46Kg
  • dimensions: 16.7 x 5.1 x 13.8"

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Due to constant product improvements the actual product appearance might differ from the shown images. Product images are for illustrative purposes only.

REACH communicating information according to article 33

USA - English (US)