Q. What sort of testing is done on the tubes?
A. The tubes are always tested at the JJ factory and they have a significant burn in phase too. Once they arrive in the UK we stick them in an amp and make sure they've not been damaged during transit. They'll hopefully have a drama free journey to you and arrive working perfectly.
Q. Can I use X tube in place of Y tube?
A. Always try and replace like for like tubes. However certain tubes can be subbed for others. The 12BH7-A can replace the ECC99 and the 5751 is a variation on the ECC83 (with reduced gain). The opposite is also true. Consult your amp / audio manufacturer before you attempt a sub.
Q. Is matching needed?
A. Not usually on pre amp tubes, but sometimes on power amp tubes. It usually comes down to personal taste. The amp will run fine with non matched tubes as long as it's biased correctly.
Q. What are the characteristics of JJ tubes?
A. JJ tubes are often described as tight yet punchy with minimal distortion. They're often seen as one of the more reliable and consistent brands.
Q. I don't understand tubes at all. Help.
A. We've written a beginners guide to tubes here. It covers the basics and should give you a base level of understanding when it comes to tubes in audio devices.
Q. I've heard about gold pin varieties - are they better.
A. Again this is usually subjective. But we don't think so. It's the construction and design of the tube on the inside which matters. Gold does conduct better, but it doesn't impact tone.