Related Manuals for VAC Phi 220
Summary of Contents for VAC Phi 220
- Page 1 110/110 The VAC Phi Two Twenty Monophonic Beam Power Amplifier & Phi 110/110 Stereo Beam Power Amplifier Operation & Maintenance Information Valve Amplification Company Manual issued 01/24/2004 Revised 07/02/2004...
- Page 2 This tube must be replaced. (Note: The LED’s for the other tubes will show green after a few minutes...this should be disregarded.) To minimize difficulties, always source genuine VAC Tested audio tubes for your Phi.
- Page 3 CAUTION THE AMPLIFIER AND POWER SUPPLY CONTAIN NO USER SERVICEABLE PARTS. DO NOT REMOVE THE BOTTOM PLATES OR CHASSIS COVERS. LETHAL VOLTAGES ARE PRESENT WITHIN THE CHASSIS. DO NOT OPERATE THE UNITS IF THEY ARE WET. VACUUM TUBES BECOME HOT ENOUGH TO CAUSE SERIOUS BURNS. NEVER TOUCH A TUBE WHEN THE UNIT IS ON.
- Page 4 INTRODUCTION The Phi Beam Power amplifiers are unique power amplifiers, and the most power and detailed in VAC’s history. Excellent linearity is achieved without resorting to loop negative feedback, for a more natural, dimensional sound. A total of four KT88 are used in Class A1. Uniquely, each is provided with a separate DC heater supply to ensure that no undesirable couplings occur;...
-
Page 5: Unpacking And Assembly
UNPACKING & ASSEMBLY The vacuum tubes and glass covers are packed individually to prevent damage, and must be fitted to the amplifier before installation can proceed. Remove the four screws that secure the aluminum top frame to the chassis pillars using the tool provided. Turn counterclockwise to remove. Wear the supplied cotton gloves to minimize the chance of fingerprinting the nickel plated chassis. - Page 6 The front glass has the etched VAC logo. Install this between the front pillars. Take great care not to scratch this glass. The front glass fits into a small channel in the front plate. Tighten the white nylon setscrews that secure the rear glass and side glasses.
- Page 7 When loosening the metal and nylon setscrews, be careful not to back them all of the way out of the holes! If a metal screw falls into the amplifier, contact VAC for service directions. NOTE: Do not remove and connect input cables or speaker cables while is amplifier is running.
-
Page 8: Installation
Provide adequate ventilation - allow at least 3 inches above and to each side. Do not place in a completely enclosed cabinet. Do not stack other equipment on top of the VAC unit. Do not operate on carpet or any other surface that might block air flow. -
Page 9: Input Connectors
INPUT CONNECTORS XLR connection, balanced or single-ended, are made to the XLR jack on the rear panel. The INPUT SELECT toggle switch is set to the BALANCED position. The XLR connection follows the EIA “pin 2 hot” polarity convention. RCA (single ended) connection normally is made to the RCA jack on the rear panel. -
Page 10: Operation
5,000 to 10,000 hours. Any time that the VAC Power Amplifier has not been used for a few weeks the sound may be different. This is also normal for high resolution audio equipment. Optimum sound should return after a few hours of operation, preferably with an audio signal. -
Page 11: Triode & Ultra-Linear Modes
1937. Both modes of operation are available with your VAC Phi amplifier via a single switch on the top plate. Although the mode may be changed with the amplifier in operation, we strongly suggest that you... - Page 12 INSTALLING NEW OUTPUT TUBES Output tubes are type KT88. Replacement output tubes should be purchased from VAC. It is important that the tubes be checked for any tendency to mechanical or electrical shorts (see Safety Notice at the front of this manual). It is desirable that tubes be in matched quartets for each channel, and be close to the "bogey"...
- Page 13 CHECKING OUTPUT TUBE CONDITION As described at the beginning of this manual, the Phi is equipped with the KT88 Sentry circuit, which continuously monitors each output tube to ensure that it is operating within normal limits. Each tube has a corresponding indicator light on the front panel. A green indicator light will be seen as the amplifier warms up, or when a tube’s idle current is less than normal.
-
Page 14: Care Of Chassis
A Word About Low Level Tubes. CARE OF CHASSIS VAC chassis are machined aluminum for superior electromagnetic performance. The main chassis is finished in nickel plating, which is kept waxed to prevent oxidation, staining, or discoloration of the nickel. The power supply chassis is finished in durable textured gloss paint. Cleaning the units with a damp cloth WHILE THE AMP IS SWITCHED OFF AND UNPLUGGED should suffice. - Page 15 It is normal to see a slight violet glow in a power tube such as a 300B or EL34. However, a vivid violet indicates excess current flow through the tube and should be investigated. VAC can test tubes for concerned customers.
- Page 16 Your VAC Amplifier uses the KT88 kinkless tetrode. It is strongly recommended that replacement tubes be purchased only from VAC. If, however, you want to customize the sound to your tastes, be aware that as with interconnects and speaker cables, each tube manufacturer's KT88 tends to have a distinct sound, as well as its own reliability profile.
- Page 17 2 to 4 ohms 2 ohms 1 to 2 ohms (Phi 220 only) Since the impedance of most loudspeakers vary over a wide range experimentation is essential. Most speakers have a rated impedance of 4 or 8 ohms. We recommend starting with the 8 ohm connection;...
- Page 18 Keep the power supply chassis away from audio chassis and audio cables. Try different ground settings on your preamplifier, if it has them. For example, the VAC Signature, Phi, and Renaissance preamplifiers may be set to “ungrounded” or “XLR” audio modes.
-
Page 19: Specifications
SPECIFICATIONS The VAC Phi has been developed with the critical ear as the major arbiter of quality, with both conventional and unique measurements providing insight and guidance as necessary. The lack of emphasis on measurements is due to the fact that engineering's arsenal of equipment and techniques do not operate on the pattern recognition principals that control human perception of sound. -
Page 20: Warranty
Your equipment is warranted for a period of thirty (30) days from the date of purchase. In addition, if the registration form is received by VAC along with a copy of your sales receipt from an authorized VAC dealer within this thirty days, a service contract will be extended to cover your equipment for three (3) years (tubes excepted).