RENAISSANCE SEVENTY/SEVENTY Mk.
Operation & Maintenance IMPORTANT INFORMATION PLEASE READ CAREFULLY Your Renaissance Seventy/Seventy has been fitted with a thermal sensor circuit. It works in conjunction with the indicator lights located under the VAC logo on the front panel, and has two functions: 1) If the idle current in a pair of 300B output tube should drop well below acceptable limits, the light corresponding to that pair (left-most pair, left-center pair, right-center pair, right-most pair) will light green.
To minimize difficulties, always source the highest quality tubes, avoiding inexpensive or generic 300B tubes. We recommend obtaining replacement tubes from VAC, stating that they are for use in the Renaissance Seventy/Seventy. CAUTION THESE UNITS CONTAIN NO USER SERVICEABLE PARTS. DO NOT REMOVE THE BOTTOM PLATES OR TOP 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.
INDEX Introduction Unpacking Installation Operation Installing New Output Tubes Replacement of Low Level Tubes Care Of Chassis Tips and Advice A Word About Tubes in General A Word About Output Tubes A Word About Low Level Tubes A Word About Impedance Matching A Word About Feedback A Word About Grounding Tuning Your System Specifications Footnotes Warranty & Registration Form 2
INTRODUCTION The Renaissance Seventy/Seventy is a completely unique power amplifier. It allies purist amplifying devices with the power and solidity required to control modern audiophile loudspeakers. The most noticeable feature of this amplifier is the 300B filamentary triode output tube. Originally designed by Western Electric in 1935 (Footnote 1), it has several extremely desirable features that have kept it in continuous production since that time.
UNPACKING The Renaissance Seventy/Seventy is double boxed for the greatest possible protection during shipping. Tubes are packed individually to prevent damage, and must be fitted to the amplifier before installation can proceed. Each tube socket is covered by a small round sticker. On this sticker is a number that corresponds to a numbered sticker on each tube. Fit each tube into the matching socket, first removing the sticker from the amplifier and the tube. No bias level adjustment is required.
OPERATION Each channel has a separate power switch. By delay timer, 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. Best sound will be achieved after about one hour of operation. We advise against leaving the equipment on at all times for safety reasons (see Safety Notice at the front of this manual), and because of the attendant acceleration of output tube wear and power consumption.
INSTALLING NEW OUTPUT TUBES Replacement 300B output tubes should be purchased only from VAC. Output tubes are type 300B. It is important that the tubes be checked for any tendency to mechanical or electrical shorts (see Safety Notice at the front of this manual). 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. Refer to Figure 2 for the location and types of tubes.
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TIPS & ADVICE A Word About Tubes in General It is a truth 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.
A Word About Output Tubes Your VAC Amplifier uses the 300B or 300A filamentary triode. It is strongly recommended that replacement tubes be purchased only from VAC, as stated in the Safety Notice at the front ofthis manual. If, however, you want to customize the sound to your tastes, be aware that as with interconnects and speaker cables, each tube manufacturer's 300B tends to have a distinct sound. Here is a brief summary of our experiences with currently available tubes from different sources.
A Word About Low Level Tubes The Voltage Amplifier/Phase Splitter and driver tubes in the Renaissance Seventy/Seventy is the 6SN7 medium mu octal twin triode. Your amplifier is fitted with the current production British/Chinese Golden Dragon, 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 characterize them all.
A Word About Feedback Two front panel controls (one for each channel) are provided by which controlled amounts of loop negative feedback may be introduced. The settings are as follows: Labelled 0 3 4 5 6 7 Comments no global feedback at all 3.5 dB negative feedback 4.5 dB negative feedback 5.5 dB negative feedback, compensated 6.5 dB negative feedback, compensated 7.5 dB negative feedback, compensated A given amount of feedback reduces the sensitivity of the amplifier by that amount.
Tuning Your System The VAC Renaissance has unparalleled opportunities for fine tuning your system for best subjective reproduction. At first glance this may seem a bit intimidating, but it's actually quite easy to do. Let's go step by step from the beginning. 1) Start with the Ground switch at "AF" and the two Feedback controls at "0." Connect the loudspeakers to the highest tap that encompasses the nominal impedance rating of your speakers.
SPECIFICATIONS The VAC Renaissance Seventy/Seventy 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.
WARRANTY Your equipment is warranted for a period of thirty (30) days from the date of purchase. In addition, if the registration card(s) is received by VAC along with a copy of your sales receipt from an authorized VAC dealer within this thirty days, a service contract will be extended to cover your equipment for three (3) years (tubes excepted). This warranty applies only to units sold to and operated by private individuals in the United States of America through authorized VAC dealers.
