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MC901 1-Channel Dual Mono Amplifier
 
Includes our Hybrid Drive™ technology that uses the best of vacuum tubes and solid state to produce the best sound performance
The ultimate solution for bi-amping loudspeakers: 300 Watt vacuum tube amplifier and 600 Watt solid state amplifier on one chassis
Vacuum tube section powers mid and upper drivers
Solid state section drives power hungry woofers
DualView™ Power Output Meter
 
McIntosh has been perfecting vacuum tube amplifiers since the 1940s and solid state amplifiers since the 1960s. Our amplifiers have been used at many historic events including presidential inaugurations and Woodstock, as well as in landmark sound systems like the Grateful Dead's Wall of Sound and Despacio. From that heritage comes a truly one-of-a-kind home audio amplifier only we could dream of, design and build as the ultimate solution for bi-amping loudspeakers: the McIntosh MC901 Dual Mono Amplifier.
 
The MC901 is a monoblock amplifier that drives a single speaker. But it is unlike any other monoblock amplifier. What makes the MC901 so unique is that it's two amplifiers combined into one. Adding to the uniqueness is that each amplifier is of differing design philosophies: the MC901 consists of a 300 Watt vacuum tube amplifier attached to a 600 Watt solid state amplifier on one unified chassis.
 
The MC901 includes our Hybrid Drive™ technology that uses the best of vacuum tubes and solid state to produce the best sound performance. The 300 Watt vacuum tube portion powers the speaker's mid and upper drivers via eight KT88 output tubes, plus four 12AT7 and two 12AX7A signal tubes; the solid state section delivers 600 Watts of dedicated power to the power hungry woofers. The 300 Watt vacuum tube amp in the MC901 uses our patented Unity Coupled Circuit output transformer – the same technology McIntosh was founded on in 1949 – to deliver its full 300 Watts into almost any speaker regardless if it has 2, 4 or 8 Ohm impedance. Similarly, the 600 Watt solid state amp delivers its full 600 Watts into a 2, 4 or 8 Ohm impedance speaker via our Autoformer™ technology.
 
Vacuum tubes do not perform at their best when they are amplifying lower frequencies that are not being used by the loudspeaker. With the MC901, the vacuum tube amp will not be burdened with low end reproduction as the solid state section will drive these frequencies. The two amplifier sections of the MC901 are designed to work together in a synergistic relationship and are specifically engineered to assure that each section only amplifies its intended frequencies. Each amplifier section has its own discrete power supply so neither siphons power or performance away from the other. All of this results in easy bi-amping with unparalleled performance and sound reproduction from your speakers.
 
Prior to the MC901, bi-amping a speaker required two separate amplifiers. It also required an external crossover, along with a lot of trial and error, to properly configure the two detached amplifiers so they worked together as best as possible. The MC901 solves this issue thanks to its internal, adjustable crossover with the controls easily accessible on the top of the unit. These adjustable crossover filters allow you to optimize the performance of both amplifier sections to your listening preferences. Relative gain levels for each amplifier section can be adjusted from -6dB to +3dB. A direct feed can also be connected to each amplifier section, thus bypassing the filters.
 
Specifications
 
Electronic Specifications
FTC Power Output Rating
Solid State section: 600 W
Vacuum Tube section: 300 W
Power Output per Channel
Solid State section: 600 W into 2, 4 or 8 ohms
Vacuum Tube section: 300 W into 2, 4 or 8 ohms
Number of Channels
1
Total Harmonic Distortion
Solid State section: 0.005% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20kHz
Vacuum Tube section: 0.5% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20kHz
S/N below rated output
Solid State section: 122dB
Vacuum Tube section: 112dB
Dynamic Headroom
Solid State section: 2.5dB
Vacuum Tube section: 1.2dB
Damping Factor
Solid State section: >40
Vacuum Tube section: >18
Rated Power Band
Solid State section: 20Hz to 20kHz
Vacuum Tube section: 20Hz to 20kHz
Frequency Response
Solid State section:
+0, -0.25dB from 20Hz to 20kHz
+0, -3dB from 10Hz to 100kHz
Vacuum Tube section:
+0, -0.5dB from 20Hz to 20kHz
+0, -3dB from 10Hz to 70kHz
 
Control
Remote Power Control
Yes
Multi-Channel DB25 Cable
N/A
 
Connectivity
Speaker Binding Post Type
Patented Solid Cinch™ Speaker Binding Posts
 
General Specifications
Circuit Configuration
Solid State section: Quad Balanced
Vacuum Tube section: Unity Coupled
Circuit Design
Solid State and Vacuum Tube
Mono Bridge
No
Mono Parallel
No
Output Type
Solid State section: Autoformer™
Vacuum Tube section: Unity Coupled Output Transformer
Meters
DualView™ Power Output Meter
Meter Light Switch
Yes
Balanced Input
3 (1 Solid State, 1 Vacuum Tube, 1 Composite)
Front Panel
Glass
Illumination
Direct LED
Chassis Style
Polished stainless steel & black painted steel
 
Weights & Dimensions
Unit Dimensions (W x H x D)
17-17/32" (44.5cm) x 13-3/8" (34cm) x 29-17/32" (75cm)
Unit Weight
180 lbs (81.6 kg)
Shipping Weight
200 lbs (90.7 kg)