All JJ preamptubes are selected within a close tolerance and handtested for best sound and quality. Furthermore all pins are gold plated to achieve best electrical contact. What about the sound ? It is still the famouse and well known JJ brownsound - warm and smooth.
Please check the datasheet !
JJ EL84 selected for VOX AC30
These tubes are both providing a smooth and well balanced tone which is a little bit uncharacteristically for “Made in China” tubes. They can be used in guitar/bass amps as well as in audio and HiFi tube amps. They will do a good job in both types of amps where 12AU7 and 12AT7 tubes are needed.
Often 12AT7 and 12AU7 tubes are used in stages which are designed for 12AX7 tubes. This is either to reduce the “maximum power” of the amp or just to make make the preamp a little bit gently. The biggest difference in sound will get attained with the 12AU7 instead of a 12AX7 – but at the end it is a question of taste.
Twin triode preamplifier tube used in Fender Tweed amplifiers.
