chrisbass5 Posted November 26, 2018 Share Posted November 26, 2018 My vba is being a bit tempremenatal when it comes to output volume! I’m thinking it needs a new set of power valves. It’s just had a full service and the valves all biased up, but it’s definitely dropping in output during gigs. Does anyone have any experience with replacement valve sets from other companies.......Marshall quoting £450 for the 8x6550 it uses. Just wondered if other valve sets were worth looking at, or should I bite the bullet and go for originals? Any input appreciated. Cheers. Chris. Quote Link to comment Share on other sites More sharing options...
gary mac Posted November 26, 2018 Share Posted November 26, 2018 Check out Watford valves, Quote Link to comment Share on other sites More sharing options...
chrisbass5 Posted November 26, 2018 Author Share Posted November 26, 2018 Cheers Gary. The guy who services the amp used to work for Marshall for 15 years, and when I mentioned Watford valves he just smiled...... he didn't recommend them. Have you used their valves b4? Quote Link to comment Share on other sites More sharing options...
gary mac Posted November 26, 2018 Share Posted November 26, 2018 Actually I haven't but do know plenty who have, plus the guvnor is a bassist, so he must be alright. You could make contact and see how it pans out, if you don't feel that you get the right answers or the price doesn't suit, then move on. Quote Link to comment Share on other sites More sharing options...
chrisbass5 Posted November 26, 2018 Author Share Posted November 26, 2018 Cheers bud. Quote Link to comment Share on other sites More sharing options...
bertbass Posted November 27, 2018 Share Posted November 27, 2018 (edited) Had a simliar problem with mine. It wasn't valves but dirt. The fan pulls air in from everywhere. The unused input sockets and the F/X loop sockets soon got dirty and started messing about. It might be worth checking these out first. A can of servisol is cheaper than a set of valves. Actually, a lead between the F/X sockets will cure that one but I had to have the input sockets changed as they got really dirty. Still cheaper than valves though. Edited November 27, 2018 by bertbass Quote Link to comment Share on other sites More sharing options...
VTypeV4 Posted November 27, 2018 Share Posted November 27, 2018 £450 seems rather expensive to me.. I've had good service from Watford and Hotroxx in the past. I would like to think that neither company would mislead you into buying something that wasn't appropriate for your VBA. The last two sets I bought were a quartet of EHX brand KT88s (same as the 'new Mullard' branded ones) in early 2016 (I think) for the Trace which came to around £130 delivered and the the others were a quartet of JJ brand 6L6s for the Bassman 135 about a year ago for something like £80.. As suggested above, check everything else first - I played the FX loop game with a Trace Elliot V-Type Combo 4808 many years ago so. It drove me mad but the fix was pennies. Quote Link to comment Share on other sites More sharing options...
chrisbass5 Posted November 28, 2018 Author Share Posted November 28, 2018 Thanks bertbass and VtypeV4! Good advice, and hopefully that might be the problem......but as the amp has just been fully serviced/cleaned only 3 weeks ago and only done 4 gigs since I would be very surprised if it’s dirty. But I’ll check them out. The price quoted was from Marshall themselves and yes, I thought it was really expensive lol! Cheers guys. Quote Link to comment Share on other sites More sharing options...
gary mac Posted November 28, 2018 Share Posted November 28, 2018 If you're happy to look inside the amp and assuming that you're aware of the risk involved around capacitors etc. then it's worth checking the soldering to the areas that the valves are seated in. The heat generated and vibration can cause the solder to fail, it's not always obvious until a very close inspection. Admittedly it tends to be more common with Fender amps but still worth checking. Quote Link to comment Share on other sites More sharing options...
Steve Browning Posted November 28, 2018 Share Posted November 28, 2018 Somewhat surprised you are having issues within a few days of a service! Watford Valves website has some excellent valve reviews (based on their own testing) and I ended up with Svetlana Winged C 6550's in my trusty Bass 400. Quote Link to comment Share on other sites More sharing options...
chrisbass5 Posted November 28, 2018 Author Share Posted November 28, 2018 Here's a screenshot of what was done at service.... I'm not sure about opening it up myself Gary. Suppose I could take it back and ask engineer to have another check around. Read up on Watford valves and the replacement kits they provide.... seem popular and good feedback. Will give Derek a call, after I've had it back for 2nd inspection! Cheers guys. Quote Link to comment Share on other sites More sharing options...
Twincam Posted December 1, 2018 Share Posted December 1, 2018 On 28/11/2018 at 11:56, chrisbass5 said: Here's a screenshot of what was done at service.... I'm not sure about opening it up myself Gary. Suppose I could take it back and ask engineer to have another check around. Read up on Watford valves and the replacement kits they provide.... seem popular and good feedback. Will give Derek a call, after I've had it back for 2nd inspection! Cheers guys. That all seems like an appropriate service. It's worth remembering that valves can fail anytime, even new. And if old valves were in when a bias was done it could of pushed one over the edge I suppose. As others said it could be a dirty socket, I don't see the mention of cleaning the sockets being done. So hopefully it will just be that. Quote Link to comment Share on other sites More sharing options...
chrisbass5 Posted December 1, 2018 Author Share Posted December 1, 2018 Cheers Twincam. If the jack socket contacts have been “checked” I would expect them to be cleaned at the same time (if necessary). Tried it again last night and it was great at soundcheck, but gave up after 3 songs in! I did notice after the gig though, a lot of wood dust /shavings from the drummers sticks all over the floor, my cab and spare amp! Still think it’s the valves, but he’s not helping! Quote Link to comment Share on other sites More sharing options...
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