MC3500 MK II

Vacuum Tube Amplifier

There’s no denying the historic significance of the 1969 Woodstock Music and Art Fair. There had never been anything like it, and many would argue there’s not been anything like it since. With an unexpected crowd of over 400,000 people, there was a lot that could have gone wrong – and some things did. But one aspect that’s nearly universally agreed upon was how great all the musicians sounded. That sound quality is thanks to the McIntosh MC3500 Vacuum Tube Amplifiers that exclusively powered the sound system used at Woodstock.

It was at a 2019 event to celebrate the 50th Anniversary of Woodstock where McIntosh President Charlie Randall, realizing the historical importance of the MC3500, first dreamed of bringing it back into production. That proved no easy task considering it was first designed over 50 years ago. But after more than two years of development, that dream has become reality as McIntosh is proud to announce the MC3500 Vacuum Tube Amplifier Mk II.

The MC3500 Vacuum Tube Amplifier Mk II is a conservatively rated 350 W monoblock that takes its inspiration from the original 1968-71 MC3500, and incorporates everything we have learned about vacuum tube amplifier design since the 1960s.

Upgraded to modern standards and with modern components to deliver an audio performance worthy of its predecessor and the legacy of their shared model number.

Uses our Unity Coupled Circuit output transformer, which allows the full 350 W to be safely delivered to virtually any speaker regardless if it has 2, 4 or 8 Ω impedance.

Output powered by eight EL509S high-power output vacuum tubes, which was chosen specifically due to it having many similar qualities and characteristics of the 6LQ6 “sweep tubes” used on the original MC3500.

Like the original MC3500, the MC3500 Mk II has a fully balanced driver section that utilizes three 12AX7A and one 12AT7 vacuum tubes.

Power Guard Screen Grid Sensor™ (SGS) helps prevent premature vacuum tube failure by monitoring the screen grid current in the output tubes. If the current becomes too high, Power Guard SGS dynamically attenuates the input signal in real time to keep the vacuum tubes operating at safe levels.

Sentry Monitor™ observes the output current and shuts the amplifier off if it ever exceeds safe limits.

Uses a variation of our DualView™ Power Output Meter design, with the top scale showing the power output in both W and decibels, while the bottom scale shows the amplifier warmup time.

Front panel is machined aluminum with a bead blast finish and gold anodizing that emulates the look and finish of the original MC3500. A clear glass insert covers the meter; a black glass insert at the bottom houses the knobs and illuminated lettering.

• Power Output: 350 W into 2, 4 or 8 Ω
• Rated Power Band: 20 Hz to 20 kHz
• Dynamic Headroom: 2.4 dB
• Damping Factor: > 25
• Frequency Response: +0, -0.5 dB from 20 Hz to 20 kHz; +0, -3 dB from 10 Hz to 70 kHz
• Total Harmonic Distortion: 0.3% maximum at any power level from 250 mW to rated power, 20 Hz to 20 kHz
• Signal to Noise Ratio: 120 dB below rated output
• Input Sensitivity: 3.8 V Balanced, 1.9 V Unbalanced
• Voltage Gain: 2 Ω: 23 db, 4 Ω: 26 db, 8 Ω: 29 db
• Input Impedance: 22k Ω (Balanced/Unbalanced)