VAC Musicbloc Master 300 iQ, Operation & Maintenance Information

Page 1: ...oc Mono Dual Stereo Beam Power Amplifier Operation Maintenance Information Valve Amplification Company Manual issued 01 26 2023 Valve Amplification Company Inc 2172 10th Street Sarasota FL 34237 Phone 941 952 9695 FAX 941 952 9691 ...

Page 2: ...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 UNATTENDED IN OPERATION THE AMPLIFIER I...

Page 3: ...peration Illuminated Logo Installing New Tubes Operation of the VAC iQ Circuit Care Of Chassis Tips and Advice Fuses A Word About Tubes in General Output Tubes Low Level Tubes Grounding Tuning Your System Specifications Footnotes Warranty Registration Form ...

Page 4: ...and an unvarying relationship between the output tubes and the speakers The result is more detail control and nuance from the tiniest whisper to the loudest crescendo The Musicbloc design is capable of being operated as a mono amplifier or as a dual mono stereo amplifier The chassis is machined from thick aluminum finished in a combination of hand polished metallic base coat clear coat and high te...

Page 5: ...de with RCA inputs use the upper left RCA input 05 Set the three Mono Stereo switches to the desired mode of operation 06 Install the input cables in the back panel jacks that corresponds to the switch settings selected above 07 Connect the speaker cables the black lead goes to or Ground The red lead goes to or Positive There are binding post pairs for left and right in stereo operation and anothe...

Page 6: ...r loudspeakers or the amplifier NOTE Do not operate the amplifier without loudspeakers or load resistors attached NOTE Do not operate without the ventilation grill in place NOTE Take care to keep everyone especially children and pets from being able to reach and touch the tubes which become extremely hot and could cause serious injury NOTE Never touch a tube if the glass is broken The internal str...

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Page 8: ...rmal for high resolution audio equipment Optimum sound should return after 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 resolutionaudioequipmentisinfuriatinglylong TheMaster300 ssoundwillcontinuetoseasonforapproximately 200 hours The early sound of the amplifier will be less ext...

Page 9: ...e orientation determined by the plastic keyway in the center of the base Do not use excessive force Replace the top rods before operating the amplifier The patented VAC iQ system will adjust the bias settings for the tubes automatically The front panel indicators will let you know if there is a problem with any of the KT88 tubes A slight violet glow in the tube is not cause for concern The small t...

Page 10: ...es and is self diagnosing Operation In operation the iQ circuit monitors and maintains the correct bias adjustment for the KT88 output tubes at all times regardless of the music playing The iQ system contains two other components that inform you of tube condition and protect the amplifier the operation of these two circuits is indicated by the bicolor LEDs If an LED illuminates GREEN this is an in...

Page 11: ...11 IQ System Indicators GREEN WEAK TUBE REPLACE AT YOUR CONVENIENCE RED DEFECTIVE TUBE REPLACE DO NOT USE AGAIN ...

Page 12: ...rformance 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 THE AMP MUST BE SWITCHED OFF AND UNPLUGGED and at no time may any cleaning material be allowed to get into the tube sockets or jacks ...

Page 13: ...se 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 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...

Page 14: ... 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 y...

Page 15: ...d as well as its own reliability profile Tips Low Level Tubes The Voltage Amplifier Phase Splitter and driver tubes in the Master are the 6SN7GTB medium mu octal twin triode Your amplifier is fitted with the current production VAC Tested 6SN7 from Tung Sol Russia There are dozens of versions of this tube available in new old stock NOS from a variety of sources It would be impossible to characteriz...

Page 16: ...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 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 6 The use of cheater plugs is not recommended an...

Page 17: ...esponse 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 fully balanced in this mode 12 volt trigger Illuminated logo may be switched off 8 x KT88 4 x 6SN7GTB Detachable power cord standard 15A IEC power receptacle May be factory ...

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