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New member Username: MiataPost Number: 1 Registered: Oct-04 | What causes dc leak in the amp?I keep burning voice coils and was told this is a likely suspect.Is replacing the amp the only option? |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4610 Registered: Dec-03 | most likely damaged coils would be caused by clipping.. clipping is caused usually by one of the following things: gain of amp set to high, causing the input stage to be overdriven, and resulting in distortion defined as DC voltage sent to the coils of the speakers, thus producing heat and melting them/ insufficient current for the amp due to a lacking charging system in the car for the current required for that amp, resulting again, in clipping. possibly a bad ground point, also causing insufficient current, and you guessed it, clipping those are my first guesses. class D amps also put out a lot of distortion if they're driven to peak output.. but most never are, so the hysteresis curve of distortion is low enough not to cause any real damage to the coils of the subs. This is one reason SPL competitors tend to shred subs. they drive high current class D amps at peak output, and send large amounts of distortion to the subs.. but if it gets the SPL they need, they tend not to care since most are sponsored and the speakers are replaced at the factorys' expense. |
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New member Username: MiataPost Number: 2 Registered: Oct-04 | I have a new battery and alt.,the sub control on the head unit is never more than 2 or 3 clicks from its lowest position.The fader is 85% front.So I will check the grounds and gain switch on amp.If that does'nt solve it new amp time,right? |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4637 Registered: Dec-03 | set bass on the head unit to zero set any bass boost of EQ settings on the amp to flat or off as well set the gain usually no more than half way up (in my case it's usually about a quarter turn) or use www.bcae1.com 's gain-setting guides. check that ground point make sure the amp has the proper gauge power and ground cables oh, and find the point on your head unit whereaudible distortion starts. it's usually at around 21-23 out of 30 on the volume. never turn the volume up past that point. (I use a pre-amp so I can max out the volume of the head unit to just prior to teh point of distortion, then use the pre-amp's volume control as master. this avoids ever hitting distortion points from the source signal.) those are the main points that come to mind for roasting sub coils. It's hardly ever "too much power" and usually too little power and someone trying to compensate by over-driving the amp gains or turning bass boosts up too far and causing distortion. in short, coils get fried by DC voltage being sent across them. this causes the coil to essentially become a heating element, and rather quickly, the thin coating that protects each winding of copper on the coil melts away causing a dead short across the coil. this fries the coil and it usually separates and unravels, causing the cone to "freeze up." in short, a properly installed and tuned system shouldn't ever blow a speaker if it's done right. usually you can find the cause of the problem with a little hunting. |