I have the original so it's old. One problem I have with it is what I can only describe as gulping, burping sound it gives off when I pull the power cord off of the wall socket. There is also a hum problem that can be fixed temporarily if I'd turn the volume knob hard counterclockwise. Or by tightening the nut but the humming sound would come back after a few songs and then I'd have to do the same trick again. Any permanent fix?
Buying used equipment says it all.I can't afford to spend more on the sub that I'm not taking it to my local tech. If someone in this forum has had the same problem and knows the fix and don't mind sharing it, then that would be great and I'd be very thankful. Thanks for responding, Mr. Vigne.
Hum is typically a grounding problem. Turning your vc down to make the hum go away might be simple case of a bad solder joint working its wat loose. Or it might be something more serious which will require a tech to investigate. Given your first symptom the chance of bad power supply capacitors is a possibility. Bad caps will also cause a hum.
These aren't issues the average user can solve by themself since you are unlikely to have the test gear and the materials required to do such a job. Additionally, there are dangerous/lethal Voltages inside a powered sub which could threaten your health in serious ways. The general rule is, if you have to ask how to fix it, you don't have the skills required to actually fix it.
Given the age of the Sunfire my advice would be to take it to a qualified tech rather than poke around inside and possibly make matters worse. Ask for an estimate of costs before OK'ing any actual repairs. If you decide not to fix the sub, you'll be charged for bench time but nothing more. If you fix the sub, your estimate costs will be rolled into your total repair costs. And, of course, the age of the unit might make it worth your investment in a new sub rather than having this one repaired.
The other possibility is to buy a new plate amp for the sub and bypass the existing unit. This isn't always a possibility since many subs aren't constructed for easy substitutions. But unless your sub's driver (speaker) has been damaged, this might be worth investigating. The Sunfire sub used some proprietary technology and there's no telling how well it will perform with a generic plate amp. I'm afraid you'll have to do some investigation on your own to decide which direction is best for you.
Thank you very much for your practical and sensible advice. I guess I'd have to live with this for a while but to be honest, it is something that easier to procrastinate on because it only happens when I turn off the sub.