Description Type: Vacuum Tube 350 Watts x 1-Channel A tribute to the original MC3500 – the amplifier that powered Woodstock and Inspired a Generation Unity Coupled Circuit Output Transformer Power Guard Screen Grid Sensor™, Sentry Monitor™, Solid Cinch™ speaker binding posts A TRIBUTE TO THE AMPLIFIER THAT INSPIRED A GENERATION. 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 in part to the McIntosh MC3500 Vacuum Tube Amplifiers that exclusively powered the sound system used at Woodstock.1 The MC3500 would go on to power many other influential music events. A new MC3500 Mk II (left) with an original MC3500. The MC3500 Vacuum Tube Amplifier Mk II is a conservatively rated 350 Watt 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. It has been 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 – all while adhering to the original design as much as possible. Like the original MC3500, the MC3500 Mk II uses our Unity Coupled Circuit output transformer, which allows the full 350 Watts to be safely delivered to virtually any speaker regardless if it has 2, 4 or 8-Ohm impedance. The MC3500 Mk II is powered by eight EL509S high-power output vacuum tubes. The EL509S tube was chosen specifically due to it having many similar qualities and characteristics of the 6LQ6 “sweep tubes” used on the original MC3500. Like the 6LQ6, the EL509S is very rugged thanks to its robust cathode and associated heating element which produces a high peak plate current capability in excess of 1 Amp. Sweep tubes like the original 6LQ6 were primarily designed for 1950-60s era TVs where they would sweep the cathode ray gun in the picture tube across the phosphor screen. This was a very power-hungry process that required these high-powered sweep tubes. The use of sweep tubes by McIntosh engineers in the original MC3500 amplifier was a very cool and innovative application. By using the high-power EL509S vacuum tubes, the MC3500 Mk II amplifier remains as faithful as possible to original MC3500 output design. In addition, just like in the original MC3500, the MC3500 Mk II uses an additional feedback loop to enhance the linearity of the output tubes. Like the original MC3500, the MC3500 Mk II has a fully balanced driver section that utilizes three 12AX7A and one 12AT7 vacuum tubes. The first 12AX7A is the differential input amp; the second is the buffer/driver for the voltage amp; the third is the voltage amp. The 12AT7 is the buffer/driver for the EL509S output tubes. All the vacuum tubes are located behind the power and output transformers, and are covered by a 12-gauge stainless steel wire cage with a black powder coated finish. The cage is shaped so that our patented, gold-plated Solid Cinch™ speaker binding posts are easily accessible even when the cage is installed. The MC3500 Mk II has handles just like the original, but they have more ergonomic design that are friendlier on your hands when moving this 121 lb. (54.9 kg) heavyweight. The base of the chassis is stainless steel polished to a mirror finish. The 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. Electronic Specifications FTC Power Output Rating 350 W Power Output per Channel 350 W into 2, 4 or 8 ohms Number of Channels 1 Total Harmonic Distortion 0.3% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20kHz <0.20% at 1W, 20Hz to 20kHz S/N below rated output 120dB Dynamic Headroom 2.4dB Damping Factor >25 Wideband Rated Power Band 20Hz to 20kHz Frequency Response 0, -0.5dB from 20Hz to 20kHz 0, -3.0dB from 10Hz to 70kHz Control Remote Power Control Yes Multi-Channel DB25 Cable N/A General Specifications Circuit Configuration Unity Coupled Circuit Design Vacuum Tube Mono Bridge No Mono Parallel No Output Type Unity Coupled Output Transformer Meters Yes Meter Light Switch Yes Balanced Input Yes Front Panel Machined aluminum with handles Illumination Direct LED Chassis Style Polished stainless steel Connectivity Speaker Binding Post Type Patented Solid Cinch™ Speaker Binding Posts Weights & Dimensions Unit Dimensions (W x H x D) 18″ (45.7cm) x 11-13/16″ (30cm) x 21-5/8″ (54.9cm) Unit Weight 121 lbs (54.9 kg) Shipping Weight 147 lbs (66.7 kg)
