Australia’s MI Amplification has a small stable of top-quality tube amps – currently the Megalith, the Revelation and the Iron Duke. The Megalith is the meanest-looking of the bunch, with understated but decidedly tough-looking cosmetics and an imposing ‘none-more-black’ colour scheme. I tested the Megalith Beta with a matching MI Amplification speaker cabinet with four US-made, 12-inch, 8 Ohm Eminence Wizard speakers in an 18mm void-free plywood enclosure.
The preamp features two independent channels (Clean and Overdrive), each with Gain, Bass, Middle, Treble, Volume and Contour controls, as well as a three-position EQ Shift switch. The Contour control works in the phase inverter, and its effect can particularly be heard in the tightness or looseness of the sound and attack. When turned to the left it emphasises fat mids, while increasing travels to the right scoop out the mids and increase the bass.
The EQ Shift switch selects between three voicings – 0 shifts the midrange frequency upwards and adds more low mids as well; 1 offers a more ‘British’ tone, with a more even frequency spread; and 2 is more scooped and ‘American.’ The Clean channel also includes a three-position Attack switch which further adjusts the tightness and response, while the Overdrive channel has a three-way Mode switch for low, medium and high gain voicings.
In the power amp, things get even more interesting. With four tubes in a push-pull configuration, you can install KT100, KT90, KT88, KT77, 6550 (this is what was in the test model), EL34 or 6CA7 power tubes for between 150 and 200 watts of output power. If that’s too much for you though, you can drop the output power to 40% by selecting the low power mode on the Standby switch.