1999 Marshall JCM2000 DSL100

Marshall high gain goodness in the form of a 100 watt JCM2000.

The JCM2000 is a great foundation for an all-rounder high gain amplifer. Unfortunately, the series was tarnished by some bad Marshall QA early on, and a bit of a ‘jack of all trades, master of none’ design.

The great thing (and fatal flaw) of the JCM2000 was that it didn’t have a distinctive sound of it’s own. It was acknowledged it had fantastic cleans (green channel 1), a pretty good crunch (red channel 1), a lacklustre high gain (green, channel 2), and a fairly pointless ‘ultra’ gain (red, channel 2).

We’ve taken that foundation, and tweaked it to become the classic Marshall it was meant to be. It’s a tighter & leaner, with more of a distinction between the Green and Red modes, but a smoother transition when switching between the two channels.

The Green mode stays in a more ‘Pexi’ style clean & distortion sound when switching from CH1 to CH2, and on the Red mode it’s JCM800-like on channel 1 and boosted/high gain JCM800 on channel 2.

We’ve also upgraded the power filtering added a choke, improved reverb circuit and three way, adjustable toggles for the resonance and presence controls.

Rebuild

First off the mark was to fix the bias issue. Luckily nothing had been damaged, just a burnt out EL34 or two, so once we installed the Dr Tube Bias kit the amp ran perfectly.

Next was the usual power circuit rebuild, we added a new stock Hammond choke and upgraded all the filter caps, swaping out the OEM Sunsungs for a mixture of Nichicon, Chemicon, Rubycon & Wurth (it was a bit tricky finding all the sizes in one manufacturer).

Upgraded quality capacitors and resistors were used in all the the circuit updates, and solders were checked and reflowed where needed.

Revoice

Once up and running and sounding better, came a plethora of playing, and a ton of reading. There’s a hell of a lot of blogs, forums, posts & opinions out there, mostly saying the same thing over and over, so after working out what we wanted the amp to sound like we modelled a few (Joey, Fortin, Headfirst) out in Spice LT and compared it to our design. After another round of computer based tweaking, we installed a ‘best of’ of mods, selecting mostly from ours and the Joey mods with a sprinkling of Headfirst.

As an added extra we also improved the resonance and mid-shift controls to actually be useful. Now they both have three-way toggles, with an adjustable 'mid-point’ so you can easily dial in your foundation sound and quickly cut or boost your Bass and Mid frequencies at the flick of a switch.

This amp is a now a leaner, meaner, tighter and yet happier version of itself.

Refurb

Refurbished in classic Green and Gold and available with a matching 4X12.