DanFold Posted October 16, 2012 Share Posted October 16, 2012 Yo folks! had my orange out put valves changed at the local music shop as I know nothing about this. They have stuck some Marshall valves in. Was happy when I got it back. But since Febuary, I have used it about 10 times, after about a month 1 needed replacing again, had that sorted, soon as got it back to the rehearsal room, the amp was so quiet and distorted. Took it straight back. Since July/aug I got it back but it's just not got the tone anymore. Works fine now, not blowing valves for fun. So I'm HOPING that it's time to change the pre amp valves. Not been changed for 5 years or so, and I use the amp rehearsing twice a week as well as gigs most weeks. Should they last longer than that preamp valves? If changing them will sort it out I'm stuck on what to buy. Been looking at Watford valves harma cryo ECC83's And the mullard cryo ECC81 they do. or what about the Russian Groove Tubes ECC83 and ECC81? Or will JJ's do the trick? Don't wanna go to the orange shop because I have been told these are Chinese made and to avoid those by a few people. I play a Gibson Les Paul Bass what does lack on the sub end some what. I don't need the amp to really distort as I have loved pedals for this. But I do want some serious punch. Can Any of you good people help me out? Cheers Quote Link to comment Share on other sites More sharing options...
iiipopes Posted October 16, 2012 Share Posted October 16, 2012 (edited) OK, there are subtle differences between brands of tubes, but if you're getting a significant volume drop, either something is wrong with a tube (worn out, internal short, etc.) or you have something going on in the chassis that needs sorting out. If it's the #1 tube going in from the jack, look for a low-noise version of your preferred tube. I prefer the Electro-Harmonix, if it can fit into the tube socket (it has a wider base and won't fit every socket). Otherwise, they don't make that much difference. Some, yes. Slight, yes. Clean - yes, a trained ear can tell the difference. But they all sound the same (albeit with just the slightest bit of background hiss difference) when cranked. For further reading about different brands of tubes and their respective performance levels: [url="http://thetubestore.com/12ax7review.html"]http://thetubestore....2ax7review.html[/url] Edited October 16, 2012 by iiipopes Quote Link to comment Share on other sites More sharing options...
DanFold Posted October 17, 2012 Author Share Posted October 17, 2012 Advice from an established tech with some pretty big names in the UK, i have just gone for some Groove Tubes. Will see how i get on! Quote Link to comment Share on other sites More sharing options...
Subthumper Posted October 17, 2012 Share Posted October 17, 2012 Did they test the pre amp valves too? The driver/phase inverter valves need to be in good order to drive 4xKT88's. The phase inverter is the middle one and the driver is the second. The first is the pre amp. Also was it biased properly? Quote Link to comment Share on other sites More sharing options...
DanFold Posted October 18, 2012 Author Share Posted October 18, 2012 Took it to HW Audio to have the KT88's changed so they sorted all that. Dunno if they tested the pre amp valves. Didn't think that was needed really. long as my new ones sound better i'm happy! if not. Back to HW it goes! Also, In an AD200b MK3, I have read the first 2 are preamp stage (ECC83 x2), the 3rd is the phase inverter (ECC81). (If you look at the valves with preamp facing you then output valves behind them...) Quote Link to comment Share on other sites More sharing options...
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