Hello Telers, I am based near Portsmouth in the South of England, and have recently purchased a Vox AC30 hand wired head. Although new, and I do not expect the valves to fail in the short term, I am aware of the need to have spares just in case. I note that it is advised that valves should be replaced in matched pairs, (inner two and outer two I think?). I cannot afford to buy a replacement set as one sees advertised, however I do see many mullard EL84 and similar on thEBay that go for sums I can afford. I have no means of testing these valves in order to match them in whatever way they are matched, and the ones that are sold as such seem to fetch more £'s per valve. So two questions: Is there anyone near me who can test valves for a reasonable price? If I just carried one EL84 and 12AX7 or similar would that suffice until I found a matched pair, and what difference would it make in the "real world"? Thank you for any help, Richard.