You've added an item to the cart! ×



For years, bassists have been combining guitar and bass amps to remarkable effect, adding harmonics and layers of overdrive from a guitar amp to their core bass tone in pursuit of the ultimate live sound. This “bi-amp” trend got us thinking: why drag two amps to the show when you could take just one? The result is the OB1 series of Class A/B rack mountable bass heads, which take care of this and much more besides.

The key to the OB1’s unique sound is our footswitchable blend circuit, which adds a veneer of controllable gain and increased harmonic content to the upper registers of the input signal. The lower frequencies and clean signal are left alone, staying just as warm and clear as they would in a “bi-amped” setup. Depending on where the Gain and Blend controls are set, the possibilities are limitless. Toggle the Blend control to achieve anything from a transparent clean boost to all-out filthy grind and everywhere in between.

OB1-300 is the 300-Watt version, sharing the same features and 2U rack dimensions as the more powerful OB1-500.

Key Features

“Bi-amp”-Inspired Design

The OB1 splits the input instrument signal into two separate paths. One amplifies the clean signal, with all the clarity you would expect from Orange. The other adds stages of gain to the upper harmonics only, controllable via the amp’s Gain knob. These two elements are combined using the amplifier’s Blend control which adjusts the balance between clean and dirty. The Blend control can then be remotely engaged or defeated using the optional footswitch.

The gain and blend range allows for almost any tone, from a subtle level boost that cuts through the mix to added girth and presence at moderate settings that fattens up chorus passages, and fully saturated savagery at the extremes. However you dial it in, the OB1 always maintains critical low-end definition, right the way up to the most offensive settings.

Active EQ

The OB1’s highly responsive active three-band EQ has been meticulously voiced for maximum effect and minimal fuss. The EQ section is located after the gain and blend in the circuit, allowing full tonal control over the entire range of sounds. The Bass and Middle controls feature ±15 dB of boost or cut, while there is a range of ±20 dB on the Treble control.

All-Analogue Signal Path

The OB1 series puts Class A/B power back on the map. All circuitry is completely analogue, ensuring these amps sound expressive and musical, even at ridiculous gain levels.

Rack-Mount Friendly

The OB1 Series are our first rack-mountable amps, suitable for 19-inch cases. Enclosed in a rugged steel chassis, the fascia is finished in Orange’s classic “pics-only” styling.

Although very much a rock amp, anyone with old-school guitar-band leanings would be happy to have one of these sitting atop their stack.

FeaturesRack-mountable (2U) “bi-amp”-inspired bass head with footswitchable Gain and Blend controls, active 3-band EQ, balanced DI & line level outputs
Front Panel (Right to Left):Instrument Input with Active/Passive Switch, Gain, Blend, Bass, Middle, Treble, Volume, Footswitch Input, Mains Switch
Rear Panel (Right to Left):Speaker Outputs (Speakon), 1/4″ Line Output, Balanced Output with Ground Lift Switch
Speaker Output Options:Minimum 4 Ohm: 1 x 8 Ohm, 2 x 8 Ohm, 1 x 4 Ohm
Output Power:300 Watts, Class A/B
Finish Options:White powder-coated steel chassis (2U 19-inch rack-mountable)
Unboxed Dimensions (W x H x D):48.2 × 26.5 x 10cm (18.97 x 10.43 x 3.93″)
Unboxed Weight:10.1kg (22.26lb)