Pair 12AX7/ECC83S JJ Tesla pre amp Tubes, Balanced and Matched Pair These are the latest generation of 12AX7 valve to come from the JJ Tesla plant in the Slovak Republic. The new design is based on the famous frame grid construction made famous by Telefunken. The main improvements are in the area of microphonics and noise. The JJ tube is a great all round valve and a very popular tube. Bought in march '08 for £20, pair has had only 10 hrs in amp. £14.00 incl P&P