Original vintage ad for McINTOSH LABORATORY INC.  The Best Amplifier.  We Challenge any other manufacturer to prove that his power amplifier will deliver full advertised power at all frequencies.  To assure highest quality and performance, every amplifier is measured by the use of these test instruments, Hewlett Packard 206A Signal Generator, Hewlett Packard 330B Distortion Analyzer, Techtronic 502 Dual Beam Oscilloscope and a Non Inductive Load Resistor.
This unique old one page 1961 high fidelity stereo component equipment trade magazine advertisement would display beautifully matted and framed.  It would make a nice accompaniment to your vintage stereo.