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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. (Be careful here, as often a tube is made by a firm other than
indicated on its label. In the heyday of tubes it was common to crossbrand between major labels,
such as GE and RCA. Today many labels do not manufacture their tubes at all, including Gold Aero
and RAM.)

This sonic variability may at first seem a liability, but further thought will reveal that it is an advantage,
just like the ability to adjust VTA on a tone arm. The owner of a tube amplifier can select those tubes
which sound like the real thing in his/her specific system. Of course, if the manufacturer you prefer
is rare you may want to purchase a few spare tubes for the future.

How long should tubes last? It has long been known in professional circles (and probably now
forgotten) that a tube such as the 12AX7 will display better performance characteristics after two
years of continual operation than when it was new. In normal use it is not unusual for a low level
tube to last 5 years or longer. Output tubes are another story, as they are continually providing
significant amounts of current. Here the sound is your best guide. Certainly a tube should be
replaced when its emission is significantly down or its transconductance is substantially out of
specification. In normal use, output tubes will last at least 2 years and perhaps more than 5 years.

It is normal to see a slight violet glow in a power tube such as a KT88. However, a vivid violet
indicates excess current flow through the tube and should be investigated.

VAC can test tubes for concerned customers.

Summary of Contents for Statement 450

Page 1: ...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 ...

Page 2: ...ACE AT ALL TIMES THE TUBE COVERS WILL BECOME HOT IN NORMAL OPERATION DO NOT SET OR SPRAY ANYTHING ON THEM Never touch a tube if the glass is broken The internal structures carry high voltage and could present a serious possibly lethal shock If a tube breaks unplug the amplifier and wait 30 minutes then remove the tube Keep flammable objects away from the amplifier DO NOT LEAVE THE AMPLIFIER UNATTE...

Page 3: ...minated 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 ...

Page 4: ... 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 The is designed not to the latest fad but to substance for the highest possible sound quality Time spent familiarizing yourself with this man...

Page 5: ...amplifier chassis on top of the power supply taking care to align the balls on top of the power supply with the cups on the bottom of the audio chassis 004 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...

Page 6: ...atches your loudspeakers 10 Connect 12 volt trigger input cables into the appropriate sockets on the back panel if desired either will slave the off on function to the external connection 11 Provide adequate ventilation allow at least 3 inches above and to each side 12 Do not place in a completely enclosed cabinet Do not stack other equipment on top of the VAC unit 13 Do not operate on carpet or a...

Page 7: ...as once a week Follow the bias procedure outlined later in this manual 22 Note that there is a front panel TEST switch this engages the eight blue LEDs used for setting or monitoring the bias settings of the KT88 tubes SeeBiasing Checking Output Tube Condition for directions NOTE Do not remove and connect input cables or speaker cables while is amplifier is running Doing so risks damage to your lo...

Page 8: ...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 Tighten as much as you can using only your fingers Insert and tighten the remaining three screw cone washer assemblies Using the provided Allen driver tighten the four screws to a gentle but firm pressure P...

Page 9: ...tion the bar is pressed to the left while the right spring pin is set into the dimple in the right side rail The amount of protrusion of each pin may be adjusted slightly if needed REMINDER 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 REMINDER Do not operate the amplifier without a loudspeaker or ...

Page 10: ...ipment Optimum soundshouldreturnafter a few hours of operation preferably with an audio signal Please note that although your VAC System has been run for 48 hours at the factory the break in time of high resolution audio equipment is infuriatingly long The Statement sound will continue to season for approximately 200hours Theearlysoundoftheamplifierwillbelessextended dynamic and coherent Then the ...

Page 11: ...as procedure outlined later in this manual Bias must be checked and adjusted when the amplifier first turns on at 60 seconds 90 seconds two minutes and five minutes In the earliest checks set the bias so that the meter read a bit to the left of center Final setting should be made after 15 30 minutes Recheck new tubes daily for the first week Whenever a tube is changed the bias settings must be che...

Page 12: ...usic no music should be playing during the adjustments Next move the TEST switch to the right Start with the V06 BIAS control Insert the supplied screwdriver or a small flat bladed screwdriver into the adjustment control and turn in clockwise until the adjacent LED just lights then turn it slightly counterclockwise until the light goes out Next go to V07 BIAS and repeat the procedure and so on thr...

Page 13: ... to the optimal performance and best sound of your amplifier Therefore we recommend obtaining replacement tubes from VAC specifying that they are for use in the Statement 450 amplifier For further information refer to Tips Advice A Word About Tubes in General and Tips Advice A Word About Low Level Tubes CARE OF CHASSIS VACchassisaremachinedaluminumforsuperiorelectromagneticperformance Themainchass...

Page 14: ...power supply Be certain to use only the fuse rating applicable to your local ac supply voltage With a high power amplifier there can be an appreciable surge of current for a few milliseconds when power is switched on Over time this can fatigue a fuse and cause it to fail at the instant that power is applied This may be considered normal In installations where the ac power is exceptionally stiff yo...

Page 15: ...of a tube amplifier can select those tubes which sound like the real thing in his her specific system Of course if the manufacturer you prefer is rare you may want to purchase a few spare tubes for the future How long should tubes last It has long been known in professional circles and probably now forgotten that a tube such as the 12AX7 will display better performance characteristics after two ye...

Page 16: ...s Low Level Tubes The Voltage Amplifier Phase Splitter and driver tubes in the Statement is the 6SN7GT medium mu octal twin triode Your amplifier is fitted with the current production VAC Tested 6SN7 from China which we find superior to the NOS types we have tried There are dozens of versions of this tube available in new old stock NOS from a variety of sources It would be impossible to characteri...

Page 17: ... 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 after you know the sound if that connection try the 4 ohm connection Choose the connection that sounds best to your ears If you bi wire your system run separate speaker leads from the amplifier to the high and low frequency transducers you may dis...

Page 18: ...zz 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 3 Keep the audio cables as close together as possible 4 Keep the AC cords away from the audio cables 5 Try different ground settings on your preamplifier if it has them For example the VAC Signature Phi and Renaissance preamplifiers ma...

Page 19: ...ollowing describes typical measured performance when operated at 120 VAC 60 Hz 450 watt mono amplifier with separate power supply Gain 39 dB SE 33 dB balanced Frequency response 4 Hz to 75 kHz Power bandwidth 20 Hz to 70 kHz Single ended input via RCA jack non inverting Balanced input via XLR jack non inverting relative to pin 2 pin 2 hot traditional EIA RCA broadcast recording standard amp is ful...

Page 20: ..._________________ ________________________________________________________________________ Telephone _______ _______ _____________ e mail __________________________________ Dealer name ________________________________ City ____________________________________ Salesperson ___________________ Purchase date ____________ Serial Number ________________ How did you first learn of VAC products __________...

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