Gallien-Krueger MB Fusion 500 main image

Gallien-Krueger MB Fusion 500

$599.00 Price Tier: Standard

4.5 (2)

Find out who is using Gallien-Krueger MB Fusion 500

0 wishlisted

5 saved

Page last updated Jun 14, 2026

Pricing and availability

We compare 600+ stores and found this item at 1 store. Prices updated June 14, 2026.

Store

Reviews

Price

5.0 (2)

$599.00 1 available Used

View Deal

Average Price: $599

Standard/Professional

$200

$801+

Price Tier

In the Bass Amplifier Heads category, Gallien-Krueger MB Fusion 500 is priced in the Standard/Professional range. This is quality gear at a fair price point, suitable for beginners, hobbyists, and pros alike.

Budget

Standard

High-end

^* Product prices and availability are updated by Equipboard every 24hrs and are subject to change. Equipboard may receive compensation for purchases made at participating retailers linked on this site. This compensation does not affect what products or prices are displayed, or the order of prices listed. For more information, please refer to our affiliate disclosure.

Description

Edit description

Unleash your bass's full potential with the Gallien-Krueger MB Fusion 500, a powerhouse in a compact form. This bass amplifier head integrates the iconic 3x12AX7 tube preamp, offering the warmth and depth that tube enthusiasts crave. Marrying vintage tube tones with the modern reliability of a solid-state power section, this amp pumps out a robust 500 watts at 4 ohms or 350 watts at 8 ohms, making it perfect for both intimate gigs and larger venues.

The MB Fusion 500 is not just about raw power; it's about precision and versatility. Its 4-band active EQ allows for meticulous sound shaping, while the variable contour and mid-frequency select options give you the freedom to carve out your unique sound. Whether you're into rock, funk, or jazz, this amp head adapts effortlessly to any musical style.

Weighing in at under 4 lbs, the MB Fusion 500 is as portable as it is potent, easily slipping into your gig bag for ultimate convenience. Professional features such as an effects loop, XLR direct out with a ground lift switch, and speakON connectors ensure that this amplifier head is ready for any stage or studio setup, making it a must-have for any serious bassist.

Key Features:

500W at 4 ohms, 350W at 8 ohms
All-tube 3x12AX7 preamp
4-band active EQ with variable contour and mid-frequency select
Effects loop for post-EQ pedal integration
XLR direct out with ground lift switch
Ultra-lightweight and portable design

Product specs

Brand	Gallien-Krueger
Model	MB Fusion 500W Tube Preamp Ultra-Light Bass Head
Finish	Black
Year	2010s
Categories	Bass Heads
Color Family	Black
Electronics	Hybrid
Impedance	4 ohms
Number of Channels	1 Channel
Number of Inputs	1 Input
Output Power (Watts)	500
Power Tube Type	None

FAQs

What makes the Gallien-Krueger MB Fusion 500 suitable for live performances?: The Gallien-Krueger MB Fusion 500 offers 500 watts of power, making it ideal for live performances. Its lightweight design and all-tube preamp with a 4-band active EQ provide versatile tone shaping, while the footswitchable boost and contour control enhance performance dynamics.
How does the hybrid design of the MB Fusion 500 affect its sound?: The hybrid design combines a tube preamp with a digital power amp, delivering the warmth and richness of tubes with the efficiency and power of digital amplification. This results in a versatile sound suitable for various playing styles and genres.
Can I use the Gallien-Krueger MB Fusion 500 with both active and passive basses?: Yes, the MB Fusion 500 features an active/passive switch with a -14dB pad, allowing it to accommodate both active and passive bass pickups effectively.
What connectivity options does the MB Fusion 500 provide for different setups?: The MB Fusion 500 includes line out, headphone out, tuner out, and XLR out with pre/post EQ options. It also features two Speakon outputs for connecting to speaker cabinets and an effects loop for integrating external effects.
Is the Gallien-Krueger MB Fusion 500 easy to transport to gigs?: Yes, the MB Fusion 500 is designed to be ultra-lightweight, making it easy to transport to gigs while still delivering powerful performance with its 500W output.

Videos

Add video

Gallien-Krueger

Gallien-Krueger MB Fusion 500 Demo by Norm Stockton

Gallien-Krueger

Gallien Krueger Mb Fusion 500 + 112 Neo Test #5

Francesco Alga Zucchi

MB Fusion 500 + SVT 410 HLF Test #6

Francesco Alga Zucchi

Gallien-Krueger - GK - MB Fusion 500 Demo

Music Go Round Albuquerque

Reviews

Add review

Owner Insights

We analyzed real musician discussions from forums and Reddit to find what players love, question, and tweak about Gallien-Krueger MB Fusion 500.

Features and functionality

0 0

The MB Fusion 500 can run one 4 Ohm cab, one 8 Ohm cab, or two 8 Ohm cabs, with the output power being 350W for 8 Ohm and 500W for 4 Ohm.
Source
0 0

The tubes in the MB Fusion 500 are central to its sound, with V1 as input gain and V2/V3 as gain stages around tone controls.
Source
0 0

The MB Fusion's dual-channel capability is valued, providing flexibility for different tonal settings.
Source

User experience

0 0

Some users report a hiss from the boost circuit, although others find it quiet even at 50% boost.
Source
0 0

It's noted that the MB-500 is lightweight enough to fit in a gig bag pocket, making it highly portable for gigs.
Source
0 0

Owners mention the MB Fusion's tone is preferred over Ampeg's entry-level all-tube amps, highlighting its perceived superior sound quality.
Source

Comparisons

0 0

The Gallien-Krueger MB-500 offers more present upper mids and a scooped high-end tone compared to the warmer Markbass Little Mark III.
Source
0 0

The MB Fusion is often compared favorably to the RB700 for its portability and modern features, though both models are praised for meeting diverse needs.
Source

Build quality

0 0

A used MB-500 with a dent near the speakon output was reported, which may contribute to noise issues.
Source

Setup and maintenance

0 0

The MB Fusion 500 uses three 12AX7 tubes, easily available at music stores or online, and they can significantly affect the amp's tonal character.
Source
0 0

Users suggest carrying a replacement 12AX7 tube as they are the most common point of failure in tube amps due to their fragile nature.
Source
0 0

It's advised to power off the amp before tube replacement to avoid high voltage risks, and to let tubes cool down before handling due to heat.
Source

Mods and upgrades

0 0

Owners recommend trying different 12AX7 tube brands in the V1 position for subtle tonal tweaks, though changes in V2 and V3 have less impact.
Source

Use cases and applications

0 0

Despite its lightweight design, the MB Fusion is not just for touring musicians; non-touring users also appreciate its convenient size and powerful output.
Source

Value and pricing

0 0

The MB Fusion is seen as having a strong price-to-feature ratio, making it an attractive option for those seeking quality and affordability in a bass amp head.
Source