Review: MGL Lead Master 50

Although we all think “Plexi” when “classic Marshall tone” is discussed, there’s a good chance that in many cases, our mind’s ear is in fact hearing the humble JMP50 2204 Master Model of the late ’70s.
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Although we all think “Plexi” when “classic Marshall tone” is discussed, there’s a good chance that in many cases, our mind’s ear is in fact hearing the humble JMP50 2204 Master Model of the late ’70s. Having earned compliments for many years on his own particularly delectable 1979 Marshall Master Model—long the preferred test amp for the Custom Shop Les Pauls and other guitars he sells at his premises in Barrington, New Hampshire—Mark Bishop of Mark’s Guitar Loft decided to clone the amp to make it available for the rest of us. The result is the MGL Lead Master 50, an amp that soars from the crypt of these classic roots to do things that even the original never achieved. [See GP’s April 2017 Classic Gear for a full exposé on the JMP50 2204 Master Model.]

So why create a new rendition when used 1977-’81 2204s are available for less cash? The Lead Master 50’s raison d’être lies in taking a particularly noteworthy version of this amp and not merely blueprinting it precisely, but doing so in a fully hand-wired format (the original had a PCB-based circuit), using the best available components at every turn and adding several bonus features that make it a more useable amp to boot. The amps are hand assembled for Bishop by New Hampshire builder Guy Harvey, with much consultation from Evan Cantor, former co-owner of Bedrock Amps. The head cabinets are available either in figured hardwood (as seen here), made by Joel Paul who owns 13 Stars Custom Woodwork, or a more affordable Tolex option from Jeff Swanson, with a matching MGL 2x12 also available.

Components include a hand-wound reproduction vintage Marshall output transformer from renowned maker Chris Merren, high-quality PEC potentiometers, and SoZo signal capacitors, all mounted in a custom-made black powder-coated chassis. In addition to the traditional controls, the front panel carries the customer’s choice of a bright switch—to optionally bypass the 2204’s notoriously feisty bright cap—or what Bishop calls a “Brown switch,” as on the review model, which brings in an alternative resistor to bias the first preamp tube hotter for a sweeter, creamier sizzle. In addition to its dual speaker outs and impedance switch, the back panel boasts a Classic/Modern switch that taps different resistor values in the negative feedback loop, and a buffered FX loop with bypass switch, using a popular add-on circuit made by Metropoulos.

I tested the Lead Master 50 through a closed-back 2x12 cab with early ’80s Celestion G12-65 speakers and an open-back JDesign 1x12 with a ’70s EV SRO alnico speaker, using a Gibson 1958 Les Paul reissue and a Novo Serus J with P-90s, and found it an absolute blast at every turn. You want to craft classic rock lead tones and bovine power-chord crunch with superbly expressive dynamics and touch sensitivity? This thing delivers. Note that this is not a channel-switching amp, and although it does have two inputs—1 taking you to fully cascading-gain lead glory, and 2 bypassing a gain stage for a cleaner tone—I find the hotter #1 input the only really viable option unless you’re a drive-pedal fanatic. Yet, if so, why buy this amp at all? But, the nifty thing about this preamp design is that it is extremely sensitive not only to your pick attack, but to your guitar’s volume control, so that while it might outwardly appear a one-trick pony intended for rock players, it’s surprisingly easy to coax sweet, shimmering cleans just by dialing down your guitar. Short story: it’s an amp that’s made to be cranked up, and excels when you use it that way—winding up that Preamp control past noon even mitigates the bright cap that threatens to overpower the treble at lower volume settings, while enabling you to go from crystalline to scream all from the guitar itself. Personally, I really dug the hotter setting from the Brown switch, and the Classic/Modern switch round back helped me tailor the overdrive texture and low-end looseness to taste. Gutsy stuff, all the rock-warrior tone machine that plenty of players would ever need.

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PRICE $2,700 direct in Tolex, $3,000 direct in hardwood cabinet
CONTROLS Preamp, Master, Treble, Middle, Bass, Presence, Brown switch
POWER 50 watts
TUBES Three 12AX7s, two EL34s
EXTRAS Modern/Classic voicing switch, buffered FX loop with bypass switch, dual speaker outs with 4/8/16Ω switch
WEIGHT 38 lbs
KUDOS Outstanding build quality, and the “beyond-Marshall” tone that helped define rock.