VAC Vintage High Power - Manual

VAC VINTAGE HIGH POWER Mk II
MONOPHONIC POWER AMPLIFIER
Operating Instructions
DO NOT OPEN THIS UNIT - THERE ARE NO USER SERVICEABLE
PARTS INSIDE. DO NOT REMOVE THE BOTTOM PLATES. LETHAL
VOLTAGES ARE PRESENT WITHIN THE CHASSIS. DO NOT EXPOSE
THIS UNIT TO MOISTURE OR OPERATE IT IF WET.
VACUUM TUBES BECOME HOT ENOUGH TO CAUSE SERIOUS
BURNS. NEVER TOUCH A TUBE WHEN THE UNIT IS ON. IT MAY
TAKE SEVERAL MINUTES FOR THE TUBES TO COOL DOWN AFTER
THE UNIT IS SWITCHED OFF.
DO NOT PLUG INTO AN AC SOURCE UNTIL ALL CONNECTIONS ARE
COMPLETED.
Introduction
The Vintage High Power is a wideband low-feedback monoblock power amplifier producing
approximately 100 watts per chassis. It is largely based on the legendary Williamson circuit,
which was first published in England in 1947, and was the mainstay of the original high
fidelity movement. Notable features of this circuit include:
- direct-coupled triode input amplifier and phase splitter, resulting in low phase shift
- inherent precise balance of the phase splitter (if properly executed) at all frequencies
and level, resulting in excellent push-pull balance and low distortion
In the refined form presented in the VAC, this circuit delivers true state-of-the-art
performance, and repudiates the more complex designs seen even to this day. The output
stage features independent cathode bias for each tube, which results in excellent sound and
the most stable and maintenance free operation available anywhere.
Premium parts are employed throughout, including 14 pound 22 section bifilar-wound ultra-
wideband output transformers, polypropylene and polystyrene signal capacitors, high current
rectifiers, low ESR power supply, and proprietary wiring. The quality of parts and careful
layout allows the use of very little feedback for high sonic purity and low distortion.