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Bronze Member Username: ZbruskiPost Number: 35 Registered: Jun-04 | Let us say I have two 2 channel amps. They are the exact same except one is rated to output 1000 watts bridged @ 4 ohms and the other 1000 watts bridged @ 2 ohms. Assuming they have similiar internal components and do not have regulated power supplies, are they going to draw the same amount of amps from the electrical system if I use the same subs (of course getting the proper ohm sub/wiring properly to net the 2 and 4 ohm load)? What, if any would be the differences? SQ? I was aware the lower the resistence (ohms) the more likley noise is introduced into the system. Glass ...you have a link to any good articles explaining this? I am specifically looking at the difference between the USA-1000 and USA-1000x on this site: http://www.usamps.com/default.asp |
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Silver Member Username: JamtochristianWilliamsport, Pennsylvania USA of course! Post Number: 112 Registered: Mar-04 | First off, the output of the amplifiers impedance, whether 2 or 4 ohms doesn't really matter. However, the ammount of watts that the device is pushing does. Assuming that this is a Class AB amp, its likely using 50-60% efficiency. Now, IF they happen to use the similar electrical internal systems, and SAME power supply circuitry, there is a chance that indeed they will use the same ammound of amps. As for the Sound Quality, this will be different between the TWO, again, assuming that they have similar circuitry. Often times you see that different amplifiers put out so much THD at a given impedance. We'll say for instance 100Wx2 @4 Ohms =0.05% THD or 400x1 @2 Ohms =0.1 THD This could be the same amplifier, and considering that, you just bridged the channels. But its fictious and I did indeed make those numbers up. So, if you were to run it at the lower impedance say 2 ohms instead of 4, you're likely going to have a HIGHER THD. However, many will argue you can't ALWAYS hear it... but I'm not going to get into that. As for the amp you're looking at, the only difference is that one puts out 1000 watts with the channels bridged and pushing 2 ohms, and the other puts out the same ammount, except that the channels are bridged at 4 ohms. It'll really depend on what subs you use, what their impedance is, how many subs, and whether they're DVC or SVC. What subs are you planning to use? |
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Bronze Member Username: ZbruskiPost Number: 36 Registered: Jun-04 | I have (2) IDMAX 12s 2ohm DVC. For these speakers I would need the USA-1000 so I could get the 1000 watts bridged at 2ohms. I could also opt for the USA-2000 pushing 2000 watts bridged at 2 ohms but this car is not for competition and I don't have any neighbors I need to annoy more than usual late at night. Still I might get the USA-2000 if I can find a deal on it and have the money to upgrade my electrical system. |
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Silver Member Username: JamtochristianWilliamsport, Pennsylvania USA of course! Post Number: 114 Registered: Mar-04 | Theres a USA-2000 on ebay right now... you can prolly pick it up real cheap, i saw it yesterday, and If you don't get it... I might be if it goes for under 600. Good call on saving money for upgrading the electrical system. What are the RMS for each of the subs that you have? Because I'm thinking that if they're the ones I think they are you might not need the USA-2000... might be a little overkill. Let me know. |
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Bronze Member Username: ZbruskiPost Number: 37 Registered: Jun-04 | 1000 watts RMS http://www.imagedynamicsusa.com/website/products/IDMAX.html |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 3962 Registered: Dec-03 | everything you asked is pretty much covered here: http://www.wickedcases.com/caraudio/amplifiers.html running at 4 ohms instead of 2 ohms, the amp will have more headroom, better damping, better SNR, and a lower THD. That being said, the amp will also be larger and more expensive to put out 1Kw @ 4 ohms as opposed to 1Kw @ 2 ohms. That's why I run all of my amps at 4 ohms in my car. better sound quality. Also much more expensive. |