Hello all. I have searched but please point me in the right direction if this has been discussed many, many times before. For the last few weeks, my amplifier (more about that later) has been having issues with the clean channel. I plug my basses straight in and the volume is low - audible but low. Occasionally it will spark into life but then it will go back to its reduced state. The distortion channel works absolutely fine. After doing some reading, I came to the conclusion that the issue is a preamp valve. This is reasonable because as far as I know the valves haven't been changed since the amp was new (and I bought it second hand about five years ago). I've now purchased some new ECC83 (12AX7) valves from the helpful folks at Watford Valves and I'm awaiting delivery. I just wanted to check a few things with you guys: Firstly, is my diagnosis reasonable? Does it sound like a preamp valve issue? Secondly (here's the part where I expect some flak) the amplifier in question is actually a 1x12 guitar amplifier (Laney LC-30II). I'm quite happy with its performance - especially the distortion channel - with my basses but is there any possibility that the preamp section could be affected by regularly playing bass through an amp that is primarily intended for electric guitar? My first thoughts are 'no' and the fact that it's a 1x12 suggests that it should be able to deal with bass frequencies just fine but I thought I'd check with the vast knowledge base here. Apologies for my ignorance!