VAC Renaissance 140 - Manual (Page 9)

5
TIPS & ADVICE
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 of this 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.
Western Electric 300B & 300A (U.S.):
The original and definitive manufacturer. This tube was made by WECo through 1989. Older
production (pre-1980) is preferable to later production and is heartily recommended. World wide
supply is limited. Be careful...used tubes and WECo rejects have been seen on the market at premium
prices. Sound is very liquid in the midrange, but rather soft in the lower and higher frequency ranges.
Recent reproductions by the new Westrex company (using the Western Electric trade name under
license) have a similar sound, but require very careful matching. Good reliability. Western Electric
300A is the initial WECo production code. This tube differs from the 300B in the location of the bayonet
locator pin. Should be a good tube, although we personally have not had the opportunity to sample
them. Very rare.
VAC Tested 4-300B:
Our favorite, offering the best overall balance and detail, with excellent reliability. Highly recommended.
Golden Dragon 4-300B:
An older cousin of the current VAC Tested tube. A very good tube, open and detailed, with
performance exceeding the WECo in some areas. Note: Golden Dragon ceased selling this tube in 1999,
coincident with the cessation of that trade name. Any future use of the Golden Dragon name may be
upon entirely different tubes. VAC always had to do extensive selection and rematching of tubes from
Golden Dragon.
Cetron 300B (U.S.):
A fair tube, but a bit more prone to microphony than the WECo or Golden Dragon, with an artificially
reverberant and forward sound quality. Arc-overs observed during turn on.
JJ (Tesla) 300B:
Hard, buzzy sound, some reliability problems. Excessively high input capacitance.
Sovtek 300B:
Not capable of good life in the VAC.
Svetlana 300B:
Rather opaque, forward sound, somewhat similar to the JJ. The most recent versions with the plastic
base do not appear to be reliable.
Vaic:
Many variants produced; be certain that any you use do not draw more filament current than is called
for in the 300B specifications. Believed preferable to the KR.
KR Enterprises:
Many variants produced; be certain that any you use do not draw more filament current than is called
for in the 300B specifications.