I own a Sunfire True Subwoofer Mark II. Since day one (about 3 years ago), a 60HZ electrical ground hum is present. I found this to be the problem by arresting the hum with a HUMX sold by Ebtech: http://www.ebtechaudio.com/humxdes.html The sub is located across the room in a home theater configuration and is likely fed by a different electrical ground than what feeds the main surround system components. The HUMX works just fine most of the time with the HUMX. However, during operation under what seems to be duress, the sub cranks-up the hum again and can only be stopped by a power-off reset (unplug and re-plug). I have run another power feed from the main component room to the sub, but it still performs the same way? It hums? The hum can be arrested? but, certain audio frequencies (probably 60 HZ) will trigger the continual hum again that requires a power off/on reset. I have disconnected the cable (satellite receiver) and this does not stop the problem either.. Also disconnected the satellite power cord with no success. I have not used a signal hum arrestor. Could this be the fix?.. or is there a hardware problem with the sub? The HUMX? Or another component? Your help is is greatly appreciated? Ron Reynolds ? (501) 884-4414 ? [email protected]
Rolinda303 you are my new audio hero! I bought this used Bob Carver True Sub MK II used last season, it's been something I wanted for the last 20 years, but was disappointed with the annoying hum which you described, sand have tried several things to solve it short of shipping it out for repair. Last night I read your solution of tightening the nut on the nut on the gain control and guess what..my hum went away!!! I can't believe how simple this was. THANK-YOU for sharing!
Rita's Vintage Audio Repair is a Bob Carver Company & can repairs & updates Subs at a reasonable cost try calling them.
Everybody has the same problem the 2 1500mf 200volt capacitors are bad.....
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You may not believe this, but IT IS miraculously TRUE ! .. I read somewhere in cyberspace that a problem exist within the sub's gain control pot and all that is needed is to tighten it. So, I simply removed the gain control knob and tightened the mounting nut for the gain control. You cannot believe what a relief this turned-out to be.. The sub works perfectly and spectacularly. The HUMX is no longer needed. The sub is as quiet as a mouse. It's fixed!
So how do you do this? How do you remove the gain control knob? Is there anywhere with a step by step?
So how do you do this? How do I remove the gain control know and which one is the mounting nut? I have owned this sub for 10 years and never been able to figure out the hum. Is this something that requires opening up the unit? If so are there more detailed, step by step instructions somewhere?
Steve.. This is a very simple process. There is a volume knob on the control panel of the Sub. 1) Pull the knob off. 2) using an open end or closed end wrench, tighten the nut that holds the volume control stem to the panel. 3) slide the volume knob back on the stem.. Your done!
Steve, like Ron said, the solution is really quite simple. First, pull the ' VOLUME' knob off..it should slide right off. You will see the nut behind the knob..just tighten this nut with the appropriate wrench ( or socket ) and the hum should go away ( just be careful not to over tighten it and strip it ) This is such a simple fix for such an annoying problem. My hum went away instantly, and thankfully, hasn't come back. GOOD LUCK!
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