Bare Knuckle Pickups Forum
Forum Ringside => Tech => Topic started by: gingataff on January 18, 2010, 05:41:29 AM
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Over Christmas I went back to the UK and decided to give my old Laney AOR 3012 combo (Series I AFAIK) a bit of an overhaul.
I only get to play it once a year but I noticed a while back that the sound was becoming intermittent as well as some nasty clipping on the High input.
I replaced all the valves with some JJs and replaced most of the electrolytic caps too (a JJ 50/50, some Nichicon MUSE and F&Ts for the rest. The only ones I didn't change were the caps in the bias circuit and the small 2.2uf caps) and the problems were just the same.
I made some recordings of the amp, apologies for the low quality!
First is the clip showing the intermittent sound. Interestingly when I jump the FX loop with a patch cable it's fine.
http://www.youtube.com/watch?v=SQ3eecc_I1Q (http://www.youtube.com/watch?v=SQ3eecc_I1Q)
Secondly I made a recording where I change from High to Low input and you can hear the clipping. It sounds to me like something in the input is being overloaded. It's a lot more annoying in real life than on these clips I can assure you.
http://www.youtube.com/watch?v=iu6CbOSGXAU (http://www.youtube.com/watch?v=iu6CbOSGXAU)
Anyone have any ideas? I probably won't be able to test it again until the end of this year so there's no rush ;)
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Interestingly when I jump the FX loop with a patch cable it's fine.
http://www.youtube.com/watch?v=SQ3eecc_I1Q (http://www.youtube.com/watch?v=SQ3eecc_I1Q)
not trying to be a smartarse, but why not just leave the patch cable in all the time ???
its most likely the contacts not 'making' properly and/or dirty. try cleaning the jacks with Servisol spray cleaner, else just replace the jacks with new ones.
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Interestingly when I jump the FX loop with a patch cable it's fine.
http://www.youtube.com/watch?v=SQ3eecc_I1Q (http://www.youtube.com/watch?v=SQ3eecc_I1Q)
not trying to be a smartarse, but why not just leave the patch cable in all the time ???
its most likely the contacts not 'making' properly and/or dirty. try cleaning the jacks with Servisol spray cleaner, else just replace the jacks with new ones.
That's a fair point but I was worried that there could be some serious underlying cause would need attention rather than just covering it up.
Incidentally I did use Servisol on all the pots and jacks, but I'm sure it would be worth doing again.
Any idea on what the clipping could be? To me it sounds like something is overloading, it's certainly not nice warm valve breakup.
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clipping sounds like a f*cked speaker - have you tried the amp with a different speaker?
if that doesn't do it, I'd change out the valves - try simple things first.
after that, get the chassis out and take voltage measurements.
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clipping sounds like a f*cked speaker - have you tried the amp with a different speaker?
I did wonder if that was the case. I haven't tried another driver yet but that's a very sensible option, something with more power handling than the G12L-35.
if that doesn't do it, I'd change out the valves - try simple things first.
I did replace all the valves, and I actually tried 4 different valves in V1 and 2 or 3 in V2. There were some differences in tone of course but the clipping was the same.
One thing I was wondering was if it could be some kind of solid state clipping from the AOR boost circuit?
If that's the case then I'm really getting in over my head :crazy2:
after that, get the chassis out and take voltage measurements.
I presume you mean to look for a dodgy transformer, etc?
I'll try and read up on this as this is all quite new to me.
Thanks for your help with this, I really appreciate it and it's quite frustrating trying to troubleshoot remotely :plasma: