:lol: They finally arrived, opened up the back and realised I needed 4 valves, not 3! So for now I've left v3 alone as I seem to remember the PI (v4 I think) is more important? About to plug in to seee how it sounds.
edit - well they don't sound much different, slightly fuller/middier if anything. Haven't reduced the noise/hum at all though! Might take it to a tech to get looked at as I'm sure it wasn't this noisy when I first got it.