Leslie77s Posted November 5, 2014 Share Posted November 5, 2014 Any ideas please? my ABM 500w 410 combo just started making a terrible, big, bad & constant noise! Inside everything looks ok, no scorch marks or obvious fuse blows or pre-amp valve explosions? Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted November 5, 2014 Share Posted November 5, 2014 That is what happened to my EvoII combo, only way to stop it is to turn the power off, mute or volume knob does nothing? I replaced the valve thought it was OK, wedding gig with a couple of hundred guests just getting the second set everyone up dancing and off it went, louder than the full EV pa mid song, Ashdown at the time were useless and had no interest in service or repairs but everyone praises them now so maybe that is the best bet? proper weird nothing obvious intermittent problem, sold mine on ebay as spares or repairs for £125 (£750 new) swapped to the Genz in an emergency as I had loads of gigs never looked back. Quote Link to comment Share on other sites More sharing options...
Leslie77s Posted November 5, 2014 Author Share Posted November 5, 2014 Yeah that's it, power off is the only way to stop it and it's so loud and disturbing I was tempted to switch it off with a big stick in case it fried me! Not good news. I always thought it sounded quite good too. I'll try calling them but it's a fair age now. I'm currently using my old Bassmans and Ampeg cabs so it's not a disaster for up coming weddings etc. I'll buy a new lighter rig in the new year. Thanks for the info! Quote Link to comment Share on other sites More sharing options...
VTypeV4 Posted November 5, 2014 Share Posted November 5, 2014 I had a similar issue with a 300SMX Trace which turned out to be a dry joint on the power-stage board. Does a short, sharp whack on the top resolve the issue? It did with the Trace, I later soldered it up.. Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted November 5, 2014 Share Posted November 5, 2014 I tried banging mine all over, nothing, leave it plugged in for hours and hours with no problems then every few months BBRRRRRRRRRR! Loud is an understatement isnt it?! Quote Link to comment Share on other sites More sharing options...
Leslie77s Posted November 5, 2014 Author Share Posted November 5, 2014 I tried it again today and the Mrs nearly had a trouser accident outside the house at the bottom of the garden! I'll not be switching it on again until I get it looked at, if at all. I will try Ashdown tomorrow and post the results on here. Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted November 5, 2014 Share Posted November 5, 2014 If its doing it all the time it will be easier to fix imo Quote Link to comment Share on other sites More sharing options...
HowieBass Posted November 5, 2014 Share Posted November 5, 2014 That sounds like an amplified mains hum to me - there's supposed to be some way of working out where the issue is based on the frequency of the hum, at least with valve amps (something about whether it's 50Hz or 100Hz - I think the 100Hz hum is the rectified power after it's been converted from AC to DC). Might be the smoothing capacitor has failed? Quote Link to comment Share on other sites More sharing options...
Leslie77s Posted November 5, 2014 Author Share Posted November 5, 2014 Every time the switch is flicked. I'm hopeless with all the amp innards i'd probably do more harm than good. I just looked for any obvious damage so i will get it to a local tech. Quote Link to comment Share on other sites More sharing options...
HowieBass Posted November 5, 2014 Share Posted November 5, 2014 Smoothing capacitors are often mulitple units housed inside a big round metal can so you can't tell just by looking at the innards but I'm no amp tech so it's just a 'maybe' at the moment. Quote Link to comment Share on other sites More sharing options...
taunton-hobbit Posted November 5, 2014 Share Posted November 5, 2014 the answer lies in two words - Amp Tech - if you don't have one, find one - I've a great guy who takes forever, but he's a busy man...if you aint that technical, you need someone on side who is...it'll save you a nervous breakdown, trust me! Quote Link to comment Share on other sites More sharing options...
lefrash Posted November 5, 2014 Share Posted November 5, 2014 Funnily enough, I've got a Evo II 300 head sitting here that started doing the same thing. I never got it fixed cos I had only just had got it fixed for another thing and decided just to replace it. If you find out what was wrong and how much it cost you to fix, let us know, it might be worthwhile for me to put this one in for a check up! Quote Link to comment Share on other sites More sharing options...
Leslie77s Posted November 5, 2014 Author Share Posted November 5, 2014 I will do. It's as heavy as a truck so I may fix it and sell it on for a few quid in the next rig pot. May have more fundraising luck selling a Bassman on though Quote Link to comment Share on other sites More sharing options...
Protium Posted November 5, 2014 Share Posted November 5, 2014 FWIW I've got an ABM300 head that has taken some abuse over hundreds of gigs and the only issues I've had were one dry solder joint on the preamp and the transformer bolt coming loose. Your best bet is to contact Ashdown directly who will probably suggest sending it to them so they can diagnose. I was never asked for a single penny for the work undertaken on mine, and they also paid the return shipping. Unbeatable customer service. Quote Link to comment Share on other sites More sharing options...
Leslie77s Posted November 5, 2014 Author Share Posted November 5, 2014 Wow, that is great. I'll give it a try thank you Quote Link to comment Share on other sites More sharing options...
barkin Posted November 6, 2014 Share Posted November 6, 2014 I had a MAG head once, did the same sort of thing. Set about it with a liberal dose of Servisol in all the pots and switches, and it was right as rain again. As far as I'm aware, it's still going strong. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted November 6, 2014 Share Posted November 6, 2014 It sounds like (no pun intended..!) either a 'shot' rectifier, which converts AC to DC for the power supply, or a smoothing capacitor no longer performing its function, which is to smooth the rectified DC into a constant, non-rippling voltage; again, in the power supply. Do not turn it on again yourself. Take it to a competent repair bloke,preferably with Ashdown experience. The good news is that it should be neither difficult nor inordinately expensive to rectify (pun intended..!). Good luck with it; let us know how this progresses, please..? Quote Link to comment Share on other sites More sharing options...
Leslie77s Posted November 6, 2014 Author Share Posted November 6, 2014 I will keep you posted as seems to happen to a few Ashdown amps. Thanks for all the input again quality advice much appreciated! Quote Link to comment Share on other sites More sharing options...
Leslie77s Posted November 7, 2014 Author Share Posted November 7, 2014 Guy from Ashdown has replied with some suggestions, I'm awaiting any tech recommendations from him in my area.(Glasgow) it's quite an age now, an original Evo, so I'm sure there are limits as to what he can do. Quote Link to comment Share on other sites More sharing options...
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