Description
The McIntosh MC3500 Vacuum Tube Amplifier Mk II is a modern resurrection of one of the most iconic power amplifiers ever created. Originally designed in the late 1960s and famously used at Woodstock, the MC3500 earned legendary status for delivering unprecedented valve power under real-world conditions. More than fifty years later, McIntosh has re-engineered this historic design to meet contemporary performance standards while remaining faithful to its original character.
The MC3500 Mk II is a conservatively rated 350-watt monoblock valve amplifier, built using everything McIntosh has learned about vacuum tube design over the past five decades. At its core is the company’s patented Unity Coupled Circuit output transformer, allowing the amplifier to deliver its full rated power safely and consistently into 2, 4 or 8 ohm loudspeakers. This makes the MC3500 Mk II uniquely capable of driving demanding modern speakers while retaining the musical authority of a classic valve design.
Power is delivered by eight EL509S high-power output valves, selected specifically for their close performance characteristics to the original 6LQ6 sweep tubes used in the vintage MC3500. These valves are exceptionally robust, capable of very high peak current delivery, and are ideally suited to the MC3500’s demanding output stage. As with the original design, an additional feedback loop is employed to enhance linearity and maintain control across the full frequency range.
The fully balanced driver section uses three 12AX7A valves and one 12AT7, ensuring excellent noise rejection, stability and signal purity. All valves are positioned behind the transformers and protected by a heavy-gauge stainless steel wire cage, shaped to allow easy access to McIntosh’s patented Solid Cinch™ speaker binding posts even when the cage is installed.
To ensure long-term reliability, the MC3500 Mk II incorporates McIntosh’s advanced protection systems. Power Guard Screen Grid Sensor™ (SGS) dynamically monitors screen grid current in the output valves and attenuates the input signal if operating limits are approached, helping prevent premature valve wear. Sentry Monitor™ provides fuse-less short-circuit protection, automatically disengaging the output stage if unsafe current levels are detected.
Balanced and unbalanced inputs are provided for seamless integration with high-quality preamplifiers, along with balanced and unbalanced outputs to support bi-amping or tri-amping configurations where required.
A striking visual centrepiece is the large, centrally mounted output meter, inspired by the original MC3500 but reimagined for modern use. The meter displays both power output and warm-up status, rising gradually on power-up until the amplifier reaches full operating readiness. This not only improves usability but creates a symmetrical presentation in reference two-channel systems.
The physical construction pays meticulous homage to the original amplifier. The mirror-polished stainless steel chassis, gold-anodised machined aluminium front panel, ergonomic handles and distinctive U-shaped side rails echo the rugged touring amplifiers of the late 1960s. Even the rear rubber bumpers, originally designed to protect the amplifier during live setups, have been faithfully recreated.
At Hidden Home Technology, we specify the McIntosh MC3500 Mk II for clients seeking a statement-level valve amplifier that combines historic significance with genuine modern performance. Proper system matching, power delivery and installation are essential to realise its full potential within reference listening rooms.
Click here to see the modern solid-state alternative – McIntosh MC611 Quad Balanced Monoblock Amplifier
Click here for the McIntosh website – McIntosh MC3500 Vacuum Tube Amplifier Mk II
