The VAC Statement 450 Mono Beam Power Amplifier Operation & Maintenance Information Valve Amplification Company Manual issued 09/22/2010 Revised 01/19/2011 Revised 07/26/2011
CAUTION - SAFETY NOTICE 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. 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 Installing the front glass and top bars Input connectors Operation Illuminated Logo Installing New Output Tubes Biasing & Checking Output Tube Condition Replacement of Low Level Tubes Care Of Chassis Tips and Advice Fuses 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 Statement 450 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 front panel attenuator may be selected for aid in balancing channels. It may also be used to trim spectral balance when biamplifying. The chassis is machined from thick aluminum, finished in a metallic base coat/clear coat finish.
INSTALLATION 01) 004) Place the power supply in its final location. It is quite heavy, and will become more so when the amplifier is installed on top of it. Consider the location carefully, and use appropriate help in lifting, etc., so as to avoid injury. 02) Place one of the metal balls provided in each of the three cups on the top of the power supply.
05) Carefully install the front glass and top rails (see detailed directions in the next section of this manual). Take care not to chip or scratch the glass. 06) Set the top switch to Balanced (for use with balanced sources on XLR connector) or Single-ended (via RCA connector) as desired. 07) Set the front panel SELECT switch fully counterclockwise for full volume input, or clockwise if you wish to attenuate volume using the front panel VOLUME control.
17) Connect both of the cables between the power supply an d the audio chassis. Note that each has a locating key and a locking collar. Be sure to insert the connector properly, and fully tighten the locking collar. 18) 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. 19) Avoid power conditioners that float the ground pin.
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. Steady it with your hand; do not let go. Insert one of the provided screw/cone washer assemblies into one of the top holes in the glass. Start the screw, taking care that the threads align properly.
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.
OPERATION 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. We advise against leaving the equipment on at all times for safety reasons, and because of the attendant acceleration of output tube wear and power consumption. Life of the output tubes averages 3,000 to 8,000 hours. For best tube life, turn the amplifier off when you are not listening.
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 / 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..
REPLACEMENT OF LOW LEVEL TUBES All power must be switched off. Allow tubes to cool down. Remove the top glass cover. 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. Replace the glass cover before operating the amplifier.
TIPS & ADVICE SECTION Tips: Fuses Your amplifier is designed to use “slow blow” type fuses. These are contained in the fuse drawer built into the power receptacle. In the fuse drawer are two fuses. The one furthers in is the active fuse. The one nearer to the outside is a spare. The fuse ratings are labeled on the back of the power supply. Be certain to use only the fuse rating applicable to your local ac supply voltage.
Tips: 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 will probably find that they may not even 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 Statement is the 6SN7GT 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 Statement 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. 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.
