Car Audio Question

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Okay, this pertains to running a MP3 player direct through the RCA inputs of a 100 watt car amp (50 x 50) that may date to 70s or 80s, but does have MOSFET technology. I read that you never run an amp past 2/3 volume, but how does that apply to running a battery operated portable MP3 player direct into the amp via the headphone output of the MP3? Do I need to keep the MP3 player limited to 2/3 volume? Can I go a little higher on music recorded at lower volume levels? The amp also has an input level adjustment, which I have turned up to 2/3 of it's max level.
 
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I`d figure that the MP3 player would have a signal that would have to be boosted via amplification through an aux input,the way a tapedeck/turntable/cd player,etc works with a home stereo preamplifier.
 
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I would run the mp3 player at a higher level, and turn down the input level adjustment on the amp. I've never heard to limit the output of a portable device. If anything, that will reduce the signal to noise ratio which is a bad thing.
 

TallPaul

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Well what I am doing may be unorthodox because usually you drive the amp with a head unit. If the head unit connects by RCA I would think it is inputting a signal prior to the head unit's amp, so similar to the MP3 player input in a way. Though there may be a preamp in the head unit. Suprisingly running the mp3 at 2/3 volume makes it pretty loud, really about as loud as I want to enjoy yet avoid ear damage. But on some songs you just want to kick it up a few levels. I guess I just want to be sure I don't abuse it and the 2/3 rule is save, but perhaps wayy too conservative in this case. If I could find a volume and tone device I would wire it in, but apparently there is no such animal. It's all right, I can run it the way it is.. There also are programs that can boost the volume of the actual .wma files to a higher level (used mainly to equalize volume levels across songs so you don't have to fiddle with the volume control every song when running shuffle).
 

TallPaul

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 Originally Posted By: aquariuscsm
I`d figure that the MP3 player would have a signal that would have to be boosted via amplification through an aux input,the way a tapedeck/turntable/cd player,etc works with a home stereo preamplifier.
Yeah, in this case I probabaly could max out the MP3 player volume and lowering the level on the amp would be a safety measure. I don't know what 50x50 watts would sound like in a car, but I know I had a 10x12 bedroom years ago and a 65x65 Yamaha sterio that really rocked that room, so probably would get much louder if I ran the MP3 through a preamp. If all that is true, then there should be no chance of damaging the amp by running the MP3 max volume, which I really could not do for more than one song or sustain hearing damage.
 
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I wouldn't worry about it. What you don't want is to turn the volume up to the point where it distorts--and that should be quite noticeable if it happens.
 

TallPaul

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BTW, the amplifier has a max draw of 15 amps. I am running a 10 amp fuse. Can I assume that so long as the 10 amp fuse does not blow, I am not overdriving the amp (figuring 10 amp / 15 amp is 2/3, or am I comparing apples to oranges?).
 

TallPaul

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Well I guess I am good. I can run it at 80% of MP3 volume and don't hear any distortion, just a lot of really nice kicking bass. I'll set it for say 25 and then put an attenuator in the headphone line between the MP3 and the amp. That way I have a max volume setting I cannot exceed and easy thumbwheel volume control (to back off from that level) vs the MP3 volume control and save wear on the MP3 control. Also as suggested above, I'll set the level control on the amp to it's lowest setting. Thanks!
 
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