REVIEW: MI Amplification Iron Duke

MI Amplification is an Australian company who make killer tube amps with utterly bulletproof, road-ready construction and incredibly versatile tone. I recently got my hands on their Megalith amp for some recording and reviewing, and it blew my mind with its approach to heavy, heavy tones. It really excelled as a high-gain metal monster, but that’s not all I play, so I was stoked to see the Iron Duke arrive for this review. So I lugged it to my music room and plugged it into my 4X12 cab. Let the madness begin!

The Iron Duke is a 50 watt amp powered by a pair of EL34 output tubes – the same type used in classic Marshalls of course. The EL34 is known for its warm midrange and somewhat loose low end. In this case the tubes operate in Class A/B with their operating voltage kept low so they can be pushed without any problems. The amp can also be switched into to low power mode to get that sweet power amp distortion at lower volumes.

The Iron Duke has three 12AX7 preamp tubes, and two channels – the conservatively-named Channel 1 and Channel 2. As expected, Channel 1 is for clean to dirty tones, while Channel 2 takes off where its neighbour ends and goes all the way up to high gain sounds. Each channel has controls for Gain, Bass, Middle, Treble and two volumes. In fact, MI says there are two ways to think of the Iron Duke’s preamp: either as two independent channels with a foot-switchable boost, or as four pseudo channels, each pair of which shares EQ and gain controls but with independent volume controls. Each of the two main channels also has a three-position Attack switch, while all four of the ‘virtual’ channels has an on/off Mod switch which alters the tonal response. There are also negative feedback-informed Presence and Depth controls, and a three-way Depth Frequency switch which re-voices the low end. The Green channel (Channel 1) is inspired by classic British Class A. Its Mod switch extends the lows if you need to fatten things up further, and this is great for getting more girth out of thin single coils when you’re cranking those blues rock tones. The boosted version of the clean channel is voiced more like classic British amps (think Marshall stacks), except not as harsh in the high end. The Unboosted overdrive channel offers classic hard rock crunch, and the Boosted overdrive sends the gain into the stratosphere.

There’s no reverb on the Iron Duke, but you’ll find a series effects loop around the back if you really need to add some ambience from the amp end.

As mentioned, I’ve extensively played the MI Amplification Megalith amp, which is an impressive monster capable of high gain brutality of the most savage kind. And what the Megalith is to heavy, heavy tones, the Iron Duke is to rock tones. There’s an openness and clarity to the sound of the Iron Duke which really screams when you use higher gain settings with lower output humbuckers, and it gives single coils plenty of toughness instead of the relative wimpiness that some amplifiers seem to impart. I guess the overall vibe is that of an expertly modded Marshall, or perhaps a nice subtle input boost applied to a cranked Plexi and magically brought down to the point where it can sound great even at bedroom levels.

The Iron Duke is also a very responsive amp. I plugged in with my Ibanez RG7620 loaded with DiMarzio Blaze humbuckers – a scooped-midrange pickup – and used the Iron Duke’s generous Midrange control to restore some of the missing middle while cooling down just a little of the bridge pickup’s high end. What blasted forth was a woody-sounding, warm, chunky, compressed rock tone perfect for modern FM radio rock styles and 80s hard rock alike. Roll back a little on the guitar’s volume control though, and the tone opens up in a more ‘classic rock’ kind of way. In fact, players who like to ride the guitar’s volume control a lot for their gain changes are going to love this amp, as will those who need a fully-cranked, scooped-midrange, compressed-attack, 1991-Metallica-style metal tone. Actually, now that I think about it, a lot of the tones reminded me of those achieved by Mick Mars on Motley Crue’s 1994 self-titled album – the one with John Corabi on vocals. Even if you don’t like the Crue, give that album a spin to hear some killer guitar sounds and to get a bit of an idea of the breadth of tones I’m talking about. Punchy cleans, ringing jangles, muscular crunch, raunchy distortion and sometimes even full-on metal.

The Iron Duke isn’t the best death metal or metalcore amp – the Megalith more than comfortably fills that niche – but for any variant of music with ‘rock’ at the end of its name (classic rock, blues rock, hard rock, heavy rock, funk rock, jazz rock) and even some that don’t (okay, shred) the Iron Duke is perfectly voiced and expertly balanced to give you that magical combination of tone and touch that so many medium to high gain amps seem to miss out on.

The Iron Duke is an addictive playing experience because it gives you great rock tones that recall an expertly modded Marshall, but with enough identity that it sounds and feels like an MI Amplification product rather than anyone else’s. I already felt they were onto something great with the Megalith but the Iron Duke really hits it home.

[geo-out country=”Australia” note=””]This is an extended version of a review I originally wrote for Mixdown magazine.[/geo-out]