F200 The VAC Phi Two Hundred Stereo Beam Power Amplifier Operation & Maintenance Information Valve Amplification Company Manual issued 01/02/2009 Revised 03/11/2009, 01/21/2010
CAUTION - SAFETY NOTICES 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. IT MAY TAKE SEVERAL MINUTES FOR THE TUBES TO COOL DOWN AFTER THE UNIT IS SWITCHED OFF. IT IS STRONGLY RECOMMENDED THAT THE TUBE COVERS BE LEFT IN PLACE AT ALL TIMES.
INDEX Introduction Installation - Stereo Mono Connections / Mono Switch (option) Operation 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 Impedance Matching Grounding Tuning Your System Specifications Footnotes Warranty & Registration Form 2
INTRODUCTION The Phi 200 is a unique power amplifier, and one of the most vivid and detailed in VAC’s history, second only to the larger Phi 300.1. Featuring a new direct-coupled input & driver circuit, extremely fast and vivid sound is achieved from both single-ended and balanced sources. The Phi 200 may be used as a 100+ watt/channel stereo amplifier, or can be connected as a 200+ watt monophonic amplifier.
INSTALLATION - STEREO USE 01) Install the vacuum tubes. Each tube or its box has a “V” number, which corresponds to the labels on the top plate of the amplifier; these indicate where each tube should be installed. Fit each tube into the matching socket. When inserting and removing tubes, handle them by their bases, not by their glass bulbs. Note that there is a locator pin on the octal (eight contact) tubes that indicates proper alignment.
be aware that different power cords can alter the sound. 15) Check the bias settings of the output tubes when the unit is first installed and whenever a tube is changed. It is also a good idea to verify the settings periodically, such as once a week. Follow the bias procedure outlined later in this manual. NOTES: Do not remove and connect input cables or speaker cables while is amplifier is running. Doing so risks damage to your loudspeakers or the amplifier.
MONO CONNECTION - with Mono Switch option For 200+ watt mono operation: 1) 2) 3) 4) 5) 6) Set the MONO SWITCH to “Mono”. Ensure that the two BALANCE/SE switches are set identically to one another. Connect the input cable to either XLR connector (balanced source) or to either RCA connector (unbalanced source). Connect the negative speaker lead to either “COMMON” binding post. Connect the positive speaker lead to the “4-8" binding post associated with the Common post selected in step 4.
OPERATION Power on early units is applied with a front panel push button switch. Note how you are pushing the button if ‘contact bounce’ occurs, and you’ll soon acquire a reliable technique. Power on later units is applied through a front panel rocker switch. Sound will begin approximately 45 seconds after turn on. As with all high fidelity products, the sound characteristic of the VAC changes somewhat as it warms up.
INSTALLING NEW OUTPUT TUBES 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. Make certain that each tube fits firmly in its socket. ALL POWER MUST BE OFF.
CHECKING OUTPUT TUBE CONDITION The condition of each individual KT88 output tube should be checked with the built in indicator LED lights, located behind each KT88. Proper setting is indicated by an LED that is dark when no music is playing, but lights ‘with the beat’ as music is played. To achieve this setting, place the provided adjustment screwdriver in the bias adjust opening for the tube to be set.
REPLACEMENT OF LOW LEVEL TUBES All power must be switched off. Allow tubes to cool down. Remove and replace with new tubes of the appropriate types. Note that these tubes have a central platic shaft with a locator ridge on one side; this ridge must be aligned with the slot in the socket. Replacement tubes are available from VAC and other sources. For further information, refer to Tips & Advice: A Word About Tubes in General and Tips & Advice: A Word About Low Level Tubes.
TIPS & ADVICE SECTION A Word About Tubes in General It is true that each brand of tube sounds different in a particular high resolution circuit. This is because no two manufacturers make a tube type in quite the same way, and the central tendencies of the performance parameters will differ slightly with each maker. To emphasize the point, examine the plate structure of any two 6SN7 from different manufacturers and you may find that they are not the same shape and size.
Tips: Output Tubes 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. Tips: Low Level Tubes The Voltage Amplifier/Phase Splitter and driver tubes in the Phi is the 6SN7 medium mu octal twin triode.
Tips: Impedance Matching We strongly suggest that you experiment with the available impedance connections for the best sonic match with your system. Since no loudspeaker represents an unchanging impedance at all frequencies, it is impossible to assert with certainty which output tap is appropriate to use. In many systems an amazing difference in sound will exist between the various impedance taps. Since the impedance of most loudspeakers vary over a wide range experimentation is essential.
Tips: Audio Grounding Systems incorporating single-ended interconnect cables (“RCA cables”) are prone to a problem known as “ground looping”, which can result in extraneous hums and buzzes audible through the loudspeaker. If this occurs in your system, you have to attempt to minimize the ground loop. To minimize the buzz using the normal RCA input jack, there are several steps you can take: 1) Use the shortest interconnects possible. 2) Use interconnects with good shielding properties.
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 principles that control human perception of sound. In the immortal words of Daniel von Recklinghausen, if it measures good and sounds bad, it is bad.
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.
