Amplifier Heads for Bass

The Ashdown UK-OBM-500 amp head packs colossal power into an enclosure that almost fits in your hand. This 500-watt monster redefines mobility for serious bassists without sacrificing the thickness of British grain. Click to find out how this featherweight, weighing in at just 1.8kg, will dominate your next world stage.

ARTICLE N° 117822
The Ashdown UK OBM 500 turns bass amplification on its head with a power-to-weight ratio that defies physics. You hold in your hands 500 Watts of dynamic reserve, capable of filling any club or large stage without breaking your back. It's the perfect solution for rail or air nomads who demand massive acoustic impact at every stop.

Your sonic identity is sculpted with rare meticulousness thanks to the integrated 5-band equalizer. Each potentiometer targets a vital frequency zone, from the foundation at 100 Hz to the crystalline attack at 7 kHz. The Pre-shape switch activates an immediate sound profile, a signature inherited from the brand's great classics that magnifies your instrument in a second.

The on-board electronics manage voltages from 115 to 230 V completely autonomously. This internal intelligence means you can plug in your equipment anywhere in the world without the need for complex adapters or fear of power surges. For studio work or home recording, the balanced DI output delivers a signal of exemplary purity, with virtually no background noise.

The serial effects loop makes it easy to integrate your preamp or modulation pedals for a clean signal chain. The head has two jack outputs for connecting your loudspeakers with a minimum of 4 Ohms. Ashdown has come up with a robust tool, covered by a 5-year warranty, which proves that sonic authority no longer depends on the size of the chassis.
DI output
 Yes
External effects loop
 Yes
RMS power (W)
 500
Speaker output
 Yes
Frequency setting
 5 bandes
Weight
 1,8 kg
Frequency response, low limit
 22 Hz
Frequency response, upper limit
 25 kHz
Country of production
 United Kingdom
Connectors
 Jack male Mono
  • Ashdown UK-OBM-500
  • 500 W compact bass amp head
  • 500 W output power
  • Power supply 115-230 V
  • Impedance min. 4 Ω
  • Connections & I/O :
  • Speaker outputs 2 × Jack
  • High instrument input 3.9 MΩ
  • High input 150 mV-20 V p-p
  • Low instrument input 1 MΩ
  • Low input 150 mV-10 V p-p
  • Line input 10 kΩ
  • Line input 300 mV-40 V p-p
  • DI output 600 Ω balanced
  • DI level -20 dBu nominal
  • Send FX 22 kΩ
  • Send level 0 dBu nominal
  • Return FX 22 kΩ
  • Return level 0 dBu nominal
  • Performance :
  • Frequency response 22 Hz-25 kHz
  • Signal-to-noise ratio > 80 dB
  • 5-band EQ
  • Bass ±15 dB @100 Hz
  • Lo Mid ±15 dB @220 Hz
  • Middle ±15 dB @660 Hz
  • Hi Mid ±15 dB @1,6 kHz
  • Treble ±15 dB @7 kHz
  • Distortion < 0.5% THD
  • Ultra-compact format
  • Global auto-voltage
  • Clear and powerful tone
  • Integrated pre-shape
  • 5-year warranty
  • Dimensions: 220 × 89 × 209 mm
  • Weight: 1.8 kg
Ashdown - UK OBM 500
Ashdown - UK OBM 500
415,83 € excl VAT
Resupply
Arrival expected on Jun 30, 2026
Guarantee 5  years
Fred
Fred
Eric
Eric
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