: For used or vintage units, prioritize those with documented service history using original parts.
: New units typically come with a 3-year warranty in the US. Be aware that parts for vintage units can have an 8-12 week lead time. The Most Iconic McIntosh Amplifier Ever Made
Famous for powering the Grateful Dead's "Wall of Sound," this solid-state beast is a legend for those seeking high-power vintage performance.
: Check for the iconic glass front panel's condition; "bubbling" or cracks in the glass can be expensive to replace.
For a comprehensive "paper" or guide on buying a McIntosh amplifier, the best resources combine historical context, technical distinction (like the Unity Coupled Circuit), and practical purchasing advice.