I read in another thread about putting a resistor (radio shack) in between the blue turn on lead and the turn on lead going to the amp. The resistor delays the power long enough to allow the sound signal to get to the speaker first. My problem is I have a 12 volt switched wire going to a power converter which powers some amplified computer speakers that I am using for my bluetooth system. I get the 'pop' when I start the car, so I went to the shack and purchased the resistors. I disconnected the 12v lead, hooked up the resistor and hooked the other lead up after the resistor. When I hook the resistor up to the other wire, the voltage drops to 4 volts, which is not enough power to turn on the convertor. I get 12 volts after the resistor if I do not attach it to anything else, but as soon as I hook it up the voltage drops. I'm using the same model resistor that was refered to before. Any clues on why this is happening?

 

I'm not sure who got the idea of sticking a resistor in series with the amp enable line would do anything. The way the amp enable works is the input on the amp simply fires up the inverter inside based on a 12V level. There's probably some pulldown resistor on the front end to ensure it's off if nothing else is driving it, hence a resistor in series on the input simply creates a voltage divider (therefore your 4V)

THe guaranteed method is to put in a delayed turn-on. Not sure I've ever seen something sold, but if you're handy with a soldering iron and simple circuit design, you can build yourself a delay circuit that enables the amp after power is turned on. I'd image a simple LM555-based timer circuit is fairly simple to construct with a few parts for less than $1. If I remember right, the National Semiconductor site has sample circuits designs that you can simply tailor to what you need with this device.

 

Ohm's law in action!!

Anyway, the solution with a timer circuit would work just fine. Another option is a noise gate between speaker and amp source but is really too costly for what your trying to accomplish. The closest thing that you could come to any single electronic component reacting like they are saying would be a capacitor but they charge and discharge so fast I doubt it would have any impact. By all intents and purposes a capacitor in a DC circuit resists changes in voltage meaning that at power up it would gradually come up to operating voltage (when I say gradually I mean still lightning fast in our thinking) maybe .002 us from discharge to full charge which may or may not be enough to supress the pop. Anyway, if it did clear the turn on pop it may cause a turn off pop since you essentially would be powering down slightly delayed since the cap would again resist the voltage change.

 

A cap on the enable input won't do much good. To use it as a delayed turn on mechanism, the traditional approach is tying a resistor in front of it in an RC configuration. The problem with this then reverts back to the original problem.

One can indeed modify the amp if it doesn't already have a delayed turn-on. The easiest would be getting a hold of the schematics and modifying the amp accordingly.

In fact, any "stiffening" of the amp is more appropriately done inside the amp between the internal power supply and amp section. One will get a hella bigger bang for the buck there opposed to hanging some expensive multi-farad cap outside before the power supply.

 

I think you have mistaken my statement dragonman. I am not referring to a stiffening cap. I was merely speaking theoretically about delaying the turn on signal going to the amp. Moreover explaining the nature of a capacitor to be more likely to give the end result needed whereas a resistor would be way off base. Anywho, I also agree that increasing the rail voltage internally would be the best way to significantly increase power output from the amp. The problem with that is it would be cheaper to just buy the more powerful amp to begin with since more power means larger heat sink requirements as well.

 

Sorry, My bad! I confused the reply about sticking a cap on the enable line with a stiffening cap comment. The two are completely non-related. I was going off on a tangent :-)