Matt Riley Posted October 27, 2011 Share Posted October 27, 2011 Hi guys, I've been tasked with sorting out a bit of a hum in a PS8 install. It's coming from the amp, and remains, even when the inputs are unplugged, and has materialised in the last 4 months. The amp still functions correctly, but it's quite distracting. Is there anything I can check within the amp which would likely cause this increase in the noise floor? Or is it a case of stumping up for a new amp? Matt Link to comment Share on other sites More sharing options...
jamesperrett Posted October 27, 2011 Share Posted October 27, 2011 Is this an acoustic hum or is it coming through the speakers? If it is coming through the speakers then I suspect that one or more electrolytic capacitors have started to age. Testing capacitors is really a job for someone who knows what they are doing. If it is an acoustic hum then I'd suspect a loose turn in the mains transformer which will need to be replaced. James. Link to comment Share on other sites More sharing options...
Dmills Posted October 27, 2011 Share Posted October 27, 2011 When you say 'when the inputs are unplugged', do you mean the inputs to the processor or the inputs actually to the amp? I had a hum on a very similar PS10 rig that turned out to be one of the link cables from the processor to the amp that had gone single legged. Regards, Dan. Link to comment Share on other sites More sharing options...
Bobbsy Posted October 27, 2011 Share Posted October 27, 2011 I had the same question about what you meant by unplugging the inputs. However, assuming you mean fully disconnected, I've also heard hum from Yamaha amps that turned out to be electrolytics drying up, particularly those in the power supply which would take it out of regulation. Perhaps overkill but we spent a day going through changing EVERY electrolytic in the box, on the theory that, if one is going, they all will soon. At the end of that day, the beer tasted good. Link to comment Share on other sites More sharing options...
Matt Riley Posted October 28, 2011 Author Share Posted October 28, 2011 The amp inputs were fully disconnected. Sounds like it's the electrolytic then. Now to work out whether to get the caps changed or just replace the amp! Or maybe both... Matt Link to comment Share on other sites More sharing options...
ramdram Posted October 28, 2011 Share Posted October 28, 2011 There's a recent handy post on soldering...suggest you invest £5 or so in a solder sucker... Link to comment Share on other sites More sharing options...
Matt Riley Posted October 28, 2011 Author Share Posted October 28, 2011 Sadly this won't be the first time I've had to replace components in power amps (I had to diagnose and resolder a faulty transistor in a mackie M1400 a couple of years ago), nor sadly the first time I've had to do some soldering! The skills should still be there - it's just the inclination that's lacking! I'm already the proud owner of a solder sucker thanks :) Link to comment Share on other sites More sharing options...
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