woodyratm Posted August 23, 2010 Author Share Posted August 23, 2010 Right I'm going to try the above tonight. If I find that a valve or two has gone, do I just need to replace those? I am actually really hoping this is what's causing it. Is there any visable way of checking the valves? or is it just a case of seeing if they make rattling noises when tapped? Cheers guys for all the help Dave Quote Link to comment Share on other sites More sharing options...
woodyratm Posted August 23, 2010 Author Share Posted August 23, 2010 Okay - tested each power valve as advised and one is sorta tinkling when i shake it. Does this mean i just need to replace the single valve? Would that explain the lower volume and buzzing? Davie Quote Link to comment Share on other sites More sharing options...
Noisyjon Posted August 23, 2010 Share Posted August 23, 2010 (edited) I would say so. Give [url="http://www.watfordvalves.com/"]www.watfordvalves.com/[/url] a ring and talk to the bloke there, he has a great wealth of knowledge and can supply you some great new valves if needs be. Cheers, Jon edit:grammar! Edited August 23, 2010 by jonthebass Quote Link to comment Share on other sites More sharing options...
Subthumper Posted August 24, 2010 Share Posted August 24, 2010 [quote name='woodyratm' post='933996' date='Aug 23 2010, 06:30 PM']Okay - tested each power valve as advised and one is sorta tinkling when i shake it. Does this mean i just need to replace the single valve? Would that explain the lower volume and buzzing? Davie[/quote] Find a techie and have the valves tested ona proper valve tester. Quite often a valve will still work (ish) even when its gone right out of spec. Sometimes they go microphonic but work within specs and sometimes they go broke and microphonic. Also have any new valves tested before you use them, I lost a couple of hours looking for a fault in an amp and it turned out to be a brand new valve that was shorted. Buzzing similar to earth hum does sound like a duff valve, possibly one of the pre amp, drivers or buffers. Good luck cheers Just Quote Link to comment Share on other sites More sharing options...
woodyratm Posted August 24, 2010 Author Share Posted August 24, 2010 [quote name='jonthebass' post='934006' date='Aug 23 2010, 06:40 PM']I would say so. Give [url="http://www.watfordvalves.com/"]www.watfordvalves.com/[/url] a ring and talk to the bloke there, he has a great wealth of knowledge and can supply you some great new valves if needs be. Cheers, Jon edit:grammar![/quote] I gave the dude a call - He said it [i]might [/i]be the valves. Wasn't able to confirm either way if replacing the valves would fix it - he did say that the lower output did sound like the valves had died on one row. [quote name='Subthumper' post='934814' date='Aug 24 2010, 02:23 PM']Find a techie and have the valves tested ona proper valve tester. Quite often a valve will still work (ish) even when its gone right out of spec. Sometimes they go microphonic but work within specs and sometimes they go broke and microphonic. Also have any new valves tested before you use them, I lost a couple of hours looking for a fault in an amp and it turned out to be a brand new valve that was shorted. Buzzing similar to earth hum does sound like a duff valve, possibly one of the pre amp, drivers or buffers. Good luck cheers Just[/quote] Looks like this is the way forward. Might see if i can book it in one of the local shops as soon as possible for them to check it. Just a shame that it'll cost silly money to do it! Though at least Watford Valves sell the right valve needed! Quote Link to comment Share on other sites More sharing options...
Subthumper Posted August 24, 2010 Share Posted August 24, 2010 [quote name='woodyratm' post='934849' date='Aug 24 2010, 02:46 PM']I gave the dude a call - He said it [i]might [/i]be the valves. Wasn't able to confirm either way if replacing the valves would fix it - he did say that the lower output did sound like the valves had died on one row. Looks like this is the way forward. Might see if i can book it in one of the local shops as soon as possible for them to check it. Just a shame that it'll cost silly money to do it! Though at least Watford Valves sell the right valve needed![/quote] If a shop is going to sell you a set of valves then they should'nt be charging too much to test your old ones. At least valves are easy to take out and test. I recently repaired a large transistor amp that had blown some of the output devices and I had to dissmantle most of the amp to find out which ones it was. This took some come considerable time and mess ( I hate heatsink compound) and the replacement transistors were'nt far off the price of some of the lower cost valves. If its not valves then maybe its the smoothing caps. That might be my next port of call. Cheers Just Quote Link to comment Share on other sites More sharing options...
jmesa Posted August 24, 2010 Share Posted August 24, 2010 Give Mark at Westside (Glasgow) a call, he'll point you in the direction of a proper local tech for Mesa.. Quote Link to comment Share on other sites More sharing options...
woodyratm Posted August 31, 2010 Author Share Posted August 31, 2010 Thanks for all the help guys. I stuck her into the local shop and the techs checked her over. Turns out it was a dodgy transistor apparently that was causing the problems. The dude is testing it today so I'll hopefully get it back tomorrow. Quote Link to comment Share on other sites More sharing options...
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