JJ tubes are manufactured using the old Tesla tube fabrication machines which were physically moved from the Tesla Rožnov factory, Czech Republic by Jan Jorgo (JJ) to Cadca, Slovakia (some 50km east) in the early 1990s. Up until this time Tesla had a state-sponsored monopoly on electronic production in communist Czechoslovakia, producing nearly all electronic products in the country, however this ended when Czechoslovakia peacefully split into two independent countries: the Czech and Slovak Republics. Because JJ tubes are made using the same tooling as Tesla there look very similar internally. All the large Effectrode effects pedals are fitted with JJ B9A miniature dual triode vacuum tubes. These are soak tested for 24 hours to eliminate any weak tubes and then audio tested for low microphony and hum. JJ are one of the finest tubes still being produced today and are extremely reliable both mechanically and electrically – we have a very low rejection rate for microphony, especially on the ECC83s (short anode design). In our opinion JJ are about as close as you can get to a N.O.S. (new old stock) tube.