crward77 Posted January 14, 2016 Share Posted January 14, 2016 [color=#141823][font=helvetica, arial, sans-serif][size=3]I was trying to do some recording earlier but I had some issues.I use an Ashdown Mag 300 head and a 200w cab I think I may have connected the cab output cable to the line out cable. There was a couple of sparks. Power l[/size][/font][/color][color=#141823][font=helvetica, arial, sans-serif][size=3]ights are on, speaker is humming ok, but the signal isn't there. If i turn it on max the signal needled flickers very slightly. Had the top off and no sign of any blown fuses (and the front). [/size][/font][/color] [color=#141823][font=helvetica, arial, sans-serif][size=3]Thought I could smell a light electrical burn smell but no sign inside. [/size][/font][/color] [color=#141823][font=helvetica, arial, sans-serif][size=3]Any ideas, I am absolutely gutted. Any help appreciated. [/size][/font][/color] [color=#141823][font=helvetica, arial, sans-serif][size=3]Chris Ward[/size][/font][/color] [color=#141823][font=helvetica, arial, sans-serif][size=3] [/size][/font][/color] [color=#141823][font=helvetica, arial, sans-serif][size=3]frown emoticon[/size][/font][/color] Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted January 14, 2016 Share Posted January 14, 2016 Think that's one for the service department at Ashdown... Quote Link to comment Share on other sites More sharing options...
sunburstjazz1967 Posted January 14, 2016 Share Posted January 14, 2016 Thinking out loud here but could it just have blown the preamp valve by trying to power the speaker cab? Cheap and easy fix if it's possible. Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 14, 2016 Author Share Posted January 14, 2016 do you know what the valve looks like? Quote Link to comment Share on other sites More sharing options...
barkin Posted January 14, 2016 Share Posted January 14, 2016 If it's a MAG, I'm pretty sure it doesn't have any valves... Quote Link to comment Share on other sites More sharing options...
sunburstjazz1967 Posted January 14, 2016 Share Posted January 14, 2016 It's stuffed then :-( I get confused with the models, I once had a mag evo and that did have a valve. Quote Link to comment Share on other sites More sharing options...
ben4343 Posted January 15, 2016 Share Posted January 15, 2016 Definitely worth getting in touch with Ashdown and asking for some advice on how to progress with this; their customer service is top notch in my (thankfully) limited experience (MAG 420 user). Quote Link to comment Share on other sites More sharing options...
jezzaboy Posted January 15, 2016 Share Posted January 15, 2016 Take it down to your local amp guy if you have one that is! I imagine that is what Ashdown will say. Or else buy a Toneman 300 from Thomman for £207. http://www.thomann.de/gb/ashdown_toneman_300_evo_iii.htm Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 16, 2016 Author Share Posted January 16, 2016 All the fuses look fine. Replaced the smaller fuses (the big one at the back also looks fine) and checkeed the components behind the knobs. Can't spot anything. The capactors have a glue on the side, but should there be so much at the base? Are these blown? Is this the problem? I don't know if they are supposed to look like this. cheers. I Quote Link to comment Share on other sites More sharing options...
JapanAxe Posted January 16, 2016 Share Posted January 16, 2016 The big caps look normal. The gunk around the base of each cap is to stop them vibrating and breaking the circuit board tracks. Can you clarify which output socket you plugged your cable into, and what was on the other end of it? Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 16, 2016 Author Share Posted January 16, 2016 I think (i got into a muddle and discovered it wasn't working a little afterwards) I plugged the cab le that goes to the power amp into the tuner/line out on the front. (I thought I was plugging the line out into my recording box at the time) - realised when there was a plug-like spark that wasn't the case. Quote Link to comment Share on other sites More sharing options...
Merton Posted January 16, 2016 Share Posted January 16, 2016 So you plugged the speaker output into the line output? (This will be a bad thing). Or you hooked the amp up to your recording device via the line out and didn't have a speaker load present? (This shouldn't be an issue). Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 16, 2016 Author Share Posted January 16, 2016 [font=arial, sans-serif][size=3]Option A[/size][/font] Quote Link to comment Share on other sites More sharing options...
Merton Posted January 16, 2016 Share Posted January 16, 2016 sh*te, I suspect one of the output transistors has gone wonky. The only time I've blown an output tranny I couldn't tell just by looking at it ... It'll need a tech. Ashdown are very very good to deal with on these sorts of things though (I know because they're the ones who fixed my blown-up GK amp haha!) Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 16, 2016 Author Share Posted January 16, 2016 Do you know what the transistors look like. I've had it open a load of times but can't spot any obvious signs. Quote Link to comment Share on other sites More sharing options...
Merton Posted January 16, 2016 Share Posted January 16, 2016 See the big silver metal fins which look like the back of a radiator (that's essentially what they are!), the output transistors are the little black components attached to them and the PCB Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 16, 2016 Author Share Posted January 16, 2016 thanks for that. i see em. that's some of the components i can't see too well so will investigate further. cheers a lot. Quote Link to comment Share on other sites More sharing options...
Merton Posted January 16, 2016 Share Posted January 16, 2016 (edited) Good luck with it - let us know how you get on Edited January 16, 2016 by Merton Quote Link to comment Share on other sites More sharing options...
MoonBassAlpha Posted January 16, 2016 Share Posted January 16, 2016 (edited) More likely something in the preamp has got blown up. The voltage level from the speaker out will most likely be too high for the input op amp. I think it's highly unlikely the output transistors will be blown as it would represent a high impedance load. This could be good news, as op amp cost peanuts. Try putting a line level signal into the effects return socket. See if the power amp section is working at least. Edited January 16, 2016 by MoonBassAlpha Quote Link to comment Share on other sites More sharing options...
JapanAxe Posted January 16, 2016 Share Posted January 16, 2016 Chris, where do you live? There may be a local BassChatter who can help you narrow down the possibilities. Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 17, 2016 Author Share Posted January 17, 2016 yeah good thinking dude. I live in durham Quote Link to comment Share on other sites More sharing options...
Merton Posted January 17, 2016 Share Posted January 17, 2016 [quote name='MoonBassAlpha' timestamp='1452982989' post='2955373'] More likely something in the preamp has got blown up. The voltage level from the speaker out will most likely be too high for the input op amp. I think it's highly unlikely the output transistors will be blown as it would represent a high impedance load. This could be good news, as op amp cost peanuts. Try putting a line level signal into the effects return socket. See if the power amp section is working at least. [/quote] Good call Quote Link to comment Share on other sites More sharing options...
sunburstjazz1967 Posted January 17, 2016 Share Posted January 17, 2016 [quote name='MoonBassAlpha' timestamp='1452982989' post='2955373'] More likely something in the preamp has got blown up. The voltage level from the speaker out will most likely be too high for the input op amp. I think it's highly unlikely the output transistors will be blown as it would represent a high impedance load. This could be good news, as op amp cost peanuts. Try putting a line level signal into the effects return socket. See if the power amp section is working at least. [/quote] This was my initial thought regarding the preamp valve as I didn't realise it was not a mag evo but just a mag, so it's done the same thing but to the component preamp rather than the valve. Long live speakon connectors! Quote Link to comment Share on other sites More sharing options...
4stringslow Posted January 17, 2016 Share Posted January 17, 2016 [quote name='sunburstjazz1967' timestamp='1453029347' post='2955627'] Long live speakon connectors! [/quote] I agree. I've seen people with no idea (I'm not saying that's the problem in this case) attempt to cable up a small PA system and simply plug in cables at random, the main criterion seemingly being that connectors actually fit regardless of the types of signals they may be carrying. Thus, speakers into line outs is quite common I wonder if it's a hangover from the PC world? The PC industry has done a pretty good job to ensure that different signals are carried on different connectors such that it's almost impossible to hook up a PC, screw, keyboard, mouse, network and external hard drive incorrectly, while the music world still embraces a Victorian era connector! Quote Link to comment Share on other sites More sharing options...
crward77 Posted January 17, 2016 Author Share Posted January 17, 2016 First of all, thanks again for your amazing support. I had a look for an Op Amp. But i couldn't see anything that looks like this... which is an op amp on wikipedia. Also, i connected cables to the effects return ans get jack in crackles, so I think the speaker is working. I have obtained the amp schematic from here (http://music-electronics-forum.com/attachments/23084d1366992849-mag300.pdf) can anyone spot the op amo, which may help me actually locate it on the amp. Once again, I cannot thank you enough for your support. Chris Quote Link to comment Share on other sites More sharing options...
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