Mini-Onken F120A   Shelf speaker as in Hobby Hifi 3/2017

Technical data
  • impedance: 12 Ohm
  • sensivity (2,83V/1m): 85 dB
  • size (HxWxD): 485 x 254 x 312 mm
  • frequency range (-8dB): 36 - 23000 Hz
  • crossover frequency(s): Hz
  • speaker type: bass reflex

Mini-Onken F120A is a speaker that employs a Fostex F120A fullrange driver.

Mini-Onken F120A has been developed by Bernd Timmermanns and David Dlugos.

The speaker is built in onken bassreflex technology.

The crossover consists of two RCL circuit in series and a RCL circuit in parallel to the fullrange driver. These are smoothing the frequency response and compensating the baffle step.

Between 50 Hz and 20 kHz, the frequency response of this loudspeaker is nearly linear on axis. The decay spectrum is without big faults. At medium volume, i.e. 90 dB at 1 m, the nonlinear distortions are mostly below 1% above 150 Hz.

Our kit consists of

  • Fostex F 120A full range driver
  • 0,5x PE sealing tape, 5x2 mm, 7.5 m
  • 0,5x Damping Sonofil 100 x 35 cm for 20 litres
  • Audaphon Damping 10, 970 x 470 mm, adhesive
  • Binding Post PK31, gold plated (one pair, red and black)
  • 1m Speaker cable 2x2.5 mm2, transparent
  • 0,5x Pan screws 4x20 black, 8 pieces
  • Plan for DIY kit

the crossover components (right),
to be mounted on a small wooden board.

  • Audaphon MKP CAP Superior 2.2 μF / 400 Vdc
  • Audaphon MKP CAP Superior 4.7 μF / 400 Vdc
  • Audaphon MKP CAP Superior 10 μF / 400 Vdc
  • Mundorf baked varnish air core coil BL71, 0.68 mH/0.71 Ohm
  • Mundorf baked varnish air core coil BL140, 0.10 mH/0.07 Ohm
  • Mundorf baked varnish air core coil BL140, 1.5 mH/0.38 Ohm
  • Metal-oxide resistor, 10W 8.2 Ohm (grey-red-gold)
  • Metal-oxide resistor, 10W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 10W 22 Ohm (red-red-black)

Kit without cabinet, price per speaker   - not available

Kit with high-end crossover

The high-end kit contains Clarity-Cap CMR 630 V and CSA 250 V capacitors. The coils are CFC copper foil coils and baked varnish coils for diminishing the microphonics effect. Current flowing through the coil creates a magnetic field which on itself sets the reel of wire in motion. That motion induces a voltage in the coil which adds itself to the original signal.

Kit with high-end-crossover without cabinet, price per speaker   - not available

Impedance correction

If you want to use a valve amplifier with this speaker an impedance correction should be employed. In this case the component quality is less important. Therefore, we offer only one kit. Upon request, higher quality components are available.


Price per impedance correction for one speaker, to be mounted on a small wooden board.     EUR 28,50 excl. VAT: € 23.95 / $ 26.11

universal PCBs

If you prefer to mount the crossover components on a 240 x 165 mm universal PCB instead on wood:
Universal PCB RA240, order no.. str-RA240, price per unit:   EUR 8,60 excl. VAT: € 7.23 / $ 7.88
We recommend one board per kit (two boards for a speaker pair)


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