Reviewer:
Seth Burgin
from Phoenix, AZ United States
This factory was stripped of the Tesla name by EAT European Audio Team who also uses an old Czechoslovakian Tesla factory. Tesla was the communist state run tube mfg for that country. Now the map has changed and the JJ is a Slovak tube and is OK, not bad at all, but not great. It is kind of in between a RCA 6BQ5 sound and a Mullard EL84 cleaner sound, but not quite as dynamic as either one. JJ makes nice tubes, but the 6L6GC and EL 34 share parts. This means a rebias if you use their 6L6GC. Their EL84 and E84L are both fine drop in replacements which will maybe require rebiasing. This is JJ's basic El 84. I prefer NOS tubes, but these do quite well especially in modern amps which were designed after 1990. They are not as smooth as the UK made Mullard nor as ballsy as the USA RCA, but somewhere in between. Frankly tube selection can depend a lot on which amp you own. These have a good lifespan and good S/N ratios. (not very noisy)