The Eastern Electric M156 is a monoblock power amplifier, meaning that each amplifier is monophonic and therefore two are needed for a stereo system. Designed by Alex Yeung and made in China, each amp delivers a massive 160 watts and consists of a tube compliment of four Shuguang (re-labled as Eastern Electric) EL-156’s and two 12AU7’s. If you are a tube aficionado, you may be asking yourself what the devil is an EL-156. We’ll talk more about that in a second, but as far as I know, this is the only power amp that uses them, so we’re looking at a pretty unique product here.
At 56 pounds each, the amps are built and finished immaculately in a dark gray case that extends back over about a third of the chassis, hiding the massive transformers but leaving the tubes revealed. The front panel is a silver brushed metal that has few simple controls and one big, BMW dashboard style orange power meter that doubles as a biasing indicator. A knob on the upper right switches between five detents – one for biasing each EL 156 and the center position which engages the power meter function. A switch on the bottom right toggles between “Bias Current” and “Output Power”.
Biasing is easy and painless. Simply flip the knob to “V1” and use a small screwdriver in the corresponding set screws below to position the meter over the number 40 on the lower scale. Repeat for V2 through V4 on each amp and you’re done. There is also a button on the front that powers each amp on and off with a pale blue light that indicates when the amp is on. It’s a bit redundant since the power meters are only on when the power is on – they cannot be extinguished. Fortunately, they are not so bright as to illuminate a darkened room so there is no need to turn them off.