McIntosh MC901 Amplifier

Our good friend and McIntosh factory man Paul LeMay visited yesterday and showed us something new, something wonderful, and something quite unique in the hifi world. 

McIntosh now has a reference level amplifier, the MC901 mono-block that is purpose built to bi-amplify a larger high performance bi-wire speaker.  The MC901 has a solid state bass amplifier and a tube amplifier in one chassis which is great and novel yes, but the secret sauce is the two amplifiers are engineered to work together, creating seamless power for a bi-amplified speaker. 

The MC901's tube section outputs 300 watts and the solid state section outputs 600 watts.   The MC901's signature McIntosh blue meter has two needles to track the two amplifiers within. 

Why does this exist?

To answer that, we have to go back, way back.

We've seen, heard and experimented with similar DIY schemes over the years, for example putting a mono-block 150 watt MC275 tube amplifier on a speaker's treble input and a monoblock MC611's solid state amplifier on the bass. It kind-of works, but it's really hard to get them to provide a continuous presentation where it does not sound like a powerhouse lower half speaker with a midrange centric bookshelf sitting next to it. Electronically you're pushing a house down the street using Miata and a semi, side by side.  Sonically, you're literally engineering a speaker in a sense.  To fix this disjoint, you try different speaker cables, different amplifier sizes, changing input sensitivity of the amplifier, turbo-charging, pass filters, or applying DSP.  All this hoople-doople to simply smooth the speaker's output curve back to what you have with a single amplifier or two exactly matched amplifiers driving the bi-wire input of your one speaker.

It's a little complicated. 

It's a little Frankenspeaker, frankly.

Now, finally, we have an engineered solution in one amplifier chassis. It's a brilliant idea and (frankly) these will most likely become classic amplifiers for big rig systems.  A very good application of these would be a larger Sonus Faber or McIntosh speaker, both of which can take bi-wire inputs.   Sonus Faber's respond very well to solid state power bringing out their big bass drivers, but they are also sound magical with tube amplifiers for vocals and acoustic instruments.  We've gone back and fourth with various Sf Homage and Olympica's in the store trying to decide if we prefer them with solid state or tube.  Now we can have both!

Cheers,

-John.