My Audio Innovation S500 started playing up a few days back, so I changed the KT77s for some spare EL34s I have and that sorted it. So ordered a single new KT77 from Rox - Golden lion same as the others, and narrowed it down to one bad/spent valve. With new valve in it sounds a bit odd, is this normal, as Rox supply them 'burned in'. I got the Golden lions from someone on here about a year ago, and I use the amp alot and sometimes even forget to turn it off when I go out! Should I just replace all the KT77s? Is a years heavy use considered getting one's money's worth? Is there a way of testing valves independent of one's hearing ? Actually another one of Golden Lions went about 6 months ago, so now only 2 are from that batch.
Ta.