VAC Phi 300.1 Operation & Maintenance Information

VAC Phi 300.1 Operation & Maintenance Information

Stereo/mono beam power amplifier

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F
300.1
The VAC Phi Three Hundred, "A" version
Stereo/Mono Beam Power Amplifier
Operation & Maintenance Information
Valve Amplification Company
Manual issued 03/06/2007
Revised 05/07/2008, 04/23/2009, 10/20/2009

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Summary of Contents for VAC Phi 300.1

  • Page 1 300.1 The VAC Phi Three Hundred, “A” version Stereo/Mono Beam Power Amplifier Operation & Maintenance Information Valve Amplification Company Manual issued 03/06/2007 Revised 05/07/2008, 04/23/2009, 10/20/2009...
  • Page 2 CAUTION - SAFETY NOTICE THE AMPLIFIER CONTAINS 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 3 INDEX Introduction Installation Installing the front glass and top bars Input connectors Operation Feedback Triode & Ultra-Linear Modes Illuminated Logo Installing New Output Tubes Biasing & Checking Output Tube Condition Replacement of Low Level Tubes Care Of Chassis Tips and Advice A Word About Tubes in General Output Tubes Low Level Tubes...
  • Page 4 INTRODUCTION The Phi 300 is a unique power amplifier, and the most powerful and detailed in VAC’s history. Featuring a new direct-coupled input & driver circuit, extremely fast and vivid sound is achieved from both single-ended and balanced sources. The Phi 300 may be used as a 150 watt/channel stereo amplifier, or as a 300 watt monophonic amplifier, as determined by the rear panel switch.
  • Page 5: Installation

    001) Install the vacuum tubes. Each tube or its box has a “V” number, which corresponds to the labels on the top Tube Placement - VAC Phi 300 plate of the amplifier; these indicate where each tube should be installed.
  • Page 6 Connect the power cord to the power source indicated on the rear panel (will be either 100, 120, 220, or 240 volts AC). Voltage conversions must be done at the factory of by an authorized VAC importer. Avoid power conditioners that float the ground pin.
  • Page 7 INSTALLING THE FRONT GLASS AND TOP RAILS Your amplifier has been shipped with the front glass and the top rails removed. The following steps show how these are installed. Lay the provided microfiber cloth on top of the fascia as shown. Set the glass in place.
  • Page 8 The top tube cage bars have a spring pin in each end. To install, place one of the spring pins into one of the small dimples machined into one of the side rails. In the Illustration, the pin has been located into the left side rail. To complete the installation, press the bar in the direction of the pin already inserted, and manoeuver the other end into the corresponding dimple in the other side rail, then release.
  • Page 9: Operation

    Also be aware that many components display the need for a new break in period after being transported in unheated cargo aircraft. ILLUMINATED LOGO The illumination of the front VAC logo may be dimmed or turned off via a switch on the back panel.
  • Page 10: 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 11 First, see the SAFETY NOTICE earlier in the manual. Output tubes are type KT88. Replacement output tubes should be purchased from VAC. It is desirable that tubes be in matched quartets for each channel, and be close to the "bogey" values for the major parameters.
  • Page 12 CHECKING OUTPUT TUBE CONDITION / OUTPUT TUBE BIAS ADJUSTMENT Bias settings it should be checked when you install your amplifier and approximately once every month thereafter. It must also be adjusted each time a tube is replaced. The condition of the individual KT88 output tubes is checked using the TEST switch and eight built in indicator lights (four on each side of the front panel, adjacent to the adjustment points..
  • Page 13: Care Of Chassis

    A Word About Low Level Tubes. CARE OF CHASSIS VAC chassis are machined aluminum for superior electromagnetic performance. The main chassis and the fascia are finished in an acrylic lacquer, similar to fine automobile; similar care must be taken in wiping or cleaning.
  • Page 14 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 15 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 16 Contrary to popular misconception, no power is lost due to unused output taps. For more information consult VAC Technical Monograph 90-9, which may be viewed on our wesite (http://www.vac-amps.com).
  • Page 17 Keep the audio cables as close together as possible. Keep the AC cords away from the 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 18: 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 19: 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, the warranty will be extended to two (2) years (tubes excepted). This warranty applies only to units sold in the United States of America through authorized VAC dealers and operated within the United States by the original purchaser.

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