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Gallien-Krueger MB-500 Ultra-Light 500 Watt Bass Amplifier Head


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  • Solid state preamp with digital power amp design
  • Four band active EQ section allows you to shape and mould your tone
  • Headphone/line out/chain output allows you to connect a direct (unbalanced) line out to unbalanced inputs on recording devices
  • Tuner pedal output with tuner mute switch for silent tuning
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  • Send and return jacks for connecting an outboard FX chain
  • Contour control decreases mid-range frequencies whilst boosting low and high frequencies
  • -10dB pad switch for use with basses equipped with active pickups
  • Lightweight design with a rugged chassis to offer maximum protection
  • Includes footswitch, power supply and owner's manual
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Delivery & Returns

Delivery to UK mainland addresses* is FREE on orders over £75 and up to 30kg. (As a guide, a standard electric guitar weighs approx. 3-5kg).

Delivery on orders below £75 are charged at £4.45!

Delivery to Northern Ireland, the Scottish Highlands & Islands, Isle of Man, Isle of Wight, Channel Islands and the Republic of Ireland. is weight dependant and will be indicated at the checkout

Delivery above 30kg to ANY location will vary according to weight and will be indicated at the checkout

LocationPriceStandard Delivery
UK mainland*FREE on orders over £75 £4.45 on orders under £751-3 working days
Northern Ireland, Scottish Highlands & Islands Isle of Man Isle of Wight Channel Islands Republic of Ireland£12.95 – any order value up to 30kg Over 30kg - please call1-3 working days
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The Gallien-Krueger MB-500 Ultra-Light 500 Watt Bass Amplifier Head is a lightweight yet incredibly powerful amp head that delivers a huge output. With a range of controls and features that are designed to cater to every bassist's needs, you'll wonder how you ever got along without one of these beauties in your rig.

Small but perfectly formed

The MB Series of amplifiers use a combination of solid state preamp with a digital power amp, which work together exceptionally to deliver masses of power. You have 500-Watts of power at your disposal with a 4 Ohm output, and 350-Watts with an 8 Ohm output. Super-efficient circuitry design guarantees peerless signal integrity, whilst the response cooling design ensures that your electronics are protected from the risk of overheating. The chassis is built like a tank, which is surprising when the MB-500 weighs in at just 1.7kg. It is even small enough to slot into your gig bag.

Pad switch and Mute

Next to the standard jack input you'll find the -10dB On/Off switch, which allows you to pad the input when using active pickup equipped basses. Alternatively, if you're using a passive pickup equipped bass, simply turn the switch off again. The pad button flashes red when the input is overdriven. The Mute switch allows you to silently tune or unplug your bass, preventing a signal from being sent when it is activated. The bright red indicator informs you when the Mute button is active.

Gain and Contour Controls

The Gain control allows you to attenuate the preamp gain following the input stage, which can be used alongside the input pad control to optimise the amplifier's headroom. The Contour switch works in conjunction with the active equalization, by decreasing the mid-range frequencies while boosting low and high frequencies to deliver a "scooped-out" effect.

Highly versatile EQ

The MB-500 features a four-band EQ which is finely tuned to attenuate specific frequency ranges across Bass, Low-Mid, Hi-Mid and Treble. The Bass control allows you to boost or cut around 60Hz by +10dB, delivering a fatter and looser response or a tighter low-end sound. The Low-Mid control boosts and cuts around the 250Hz +6dB/-10dB, which allows you to soften the lower-mid range or create more saturation. The Hi-Mid control boosts and cuts at the 1kHz range, which allows you to hone in on your lower string harmonics to deliver greater punchiness to your tone. The Treble control boosts and cuts at 7kHz, which allows you to soften the upper frequencies and remove high-end pop or definition, particularly useful for when you want to temper your slapping technique's response.

Boost, Master-B, Master and Limiter Controls

The MB-500 has been endowed with a Boost control, with an accompanying Master-B volume control - which is only activated when Boost is activated. The Boost function delivers gain to the circuit post EQ, allowing you to inject some muscle into your tone. By adjusting the amount of boost you can create a little sizzle or plenty of growl. The Master-B control can then be used to dictate how much of an impact this makes when activated, which can be done on the amp head itself, or via a footswitch. The Master control dictates the over amp volume level when Boost is inactive. On top of the amp you will find the Limiter button, which can be used during high volume applications to prevent the poweramp from distorting.


Along the rear panel there are a range of connections including: a Direct Output (XLR) that allows a balanced output to be sent directly to a P.A. system with a standard microphone cable; a Headphone/Line Out/Chain Out jack with a switch that allows you to send a direct (unbalanced) line output to an unbalanced input. The Chain output enables connection to a Gallien-Krueger MBP powered extension cabinet. The Headphone output allows you to silently monitor your playing for quiet practise. The Speaker output allows you to output directly to a speaker cabinet.

The MB-500 is equipped with Send and Return jacks; Send can be used to output a signal from the preamp to be fed into an FX chain post EQ, whilst the Return jack sends the signal before the Boost section. The Tuner output sends a feed from the signal stage to a tuner pedal for silent tuning during performances.

Whatever style of music you perform, from rock to reggae, funk to jazz, the Gallien-Krueger MB-500 Ultra-Light 500 Watt Bass Amplifier Head adapts to any genre with ease. Each model includes a footswitch for activating/deactivating the Boost circuitry with ease, as well as a power supply and comprehensive owner's manual.

ModelMB-200 Ultra Light 200 Watt Bass Amplifier Head
Dimensions (H x W x D) 44.45 x 279.4 x 228.67 mm
Output Power 350W @ 8 Ohms
500W @ 4 Ohms
Input Section Maximum Input Level: 0.6V Rms
With -10dB pad: 1.6V Rms
Input Impedance: 1M Ohms
Send Output Impedance: 220 Ohms
Return Input Impedance: 50K Ohms
Tuner Output Impedance: 10K Ohms Direct Output Impedance: 500 Ohms
Equalizer Bass: +/-10dB @ 60Hz
Lo-Mid: +6dB/-10dB @ 250Hz
Hi-Mid: +6dB/-10dB @ 1KHz
Treble: +/-14dB @ 7KHz
Voicing FiltersContour: +2dB @ 50Hz / -10dB @ 500Hz / +3dB @ 7 KHz
Noise-90 dB reference to 500W/350W, “A” Weighted
Amplifier Protection Full short circuit, thermal and RF protection.
Stable into reactive and mismatch loads.
Five second muted warm-up.
CoolingVariable speed fan.
Power Requirements240W (Full Power)
Included Accessories Footswitch
Power Supply
Owner's Manual
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