12 volts to 17.5 volts
Printed From: the12volt.comForum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=112516
Printed Date: May 18, 2025 at 10:21 AM
Topic: 12 volts to 17.5 volts
Posted By: pumpkinman
Subject: 12 volts to 17.5 volts
Date Posted: March 19, 2009 at 10:13 PM
Replies:
Posted By: haemphyst
Date Posted: March 20, 2009 at 12:10 AM
You can't, unless you have a separate, dedicated and discrete power system JUST for the amplifiers. The rest of the electronics in the car are ALL designed to use 12 volts (nominal). You'll fry em almost immediately with 17V. So, this means a separate 17V alternator, a 16V (8 cell) battery, additional weight, added complexity... For a daily driver? It's a waste of time, money, and LOTS of energy!
As far as the amplifiers "making twice the power at that voltage", take that claim with a grain of salt... A BIG ONE.
14.4 X 1.414 = 20.3 V
In order for ANY power supply to suddenly make twice the power, you have to supply it with 1.414 times the voltage, (in the case of 14.4V, as shown above, that's 20.3 volts, not 17.5) which will pull 1.414 times the current, which is THEN twice the power. For an amp to "make twice the power at 17 volts", then it will have to run more efficiently. Almost TWICE as efficiently, by my calculations! It can't happen. And all of those statements above assume the same efficiency of energy transfer, which DOESN'T happen as you increase current transfer. Higher current through a semiconductor will ALWAYS, ALWAYS, ALWAYS have a higher voltage drop, translating into more heat, meaning a lower efficiency. (I do just LOVE blowing manufacturer's claims out of the water...
)
Ohm's law says this:
14.4 X 1.21 = 17.5
1.21 X 1.21 = 1.46
So, according to Ohm's law, at 17.5 volts, those amplifiers CANNOT make more than 1.46 times their rated 14.4 volt power - less than 50% more... translating to less than 1dB gain... an increase that you will NEVER hear. Is it worth it to you now that it's all laid out? If it is, you, my friend, need to readjust your priorities! :)
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
As far as the amplifiers "making twice the power at that voltage", take that claim with a grain of salt... A BIG ONE.
14.4 X 1.414 = 20.3 V
In order for ANY power supply to suddenly make twice the power, you have to supply it with 1.414 times the voltage, (in the case of 14.4V, as shown above, that's 20.3 volts, not 17.5) which will pull 1.414 times the current, which is THEN twice the power. For an amp to "make twice the power at 17 volts", then it will have to run more efficiently. Almost TWICE as efficiently, by my calculations! It can't happen. And all of those statements above assume the same efficiency of energy transfer, which DOESN'T happen as you increase current transfer. Higher current through a semiconductor will ALWAYS, ALWAYS, ALWAYS have a higher voltage drop, translating into more heat, meaning a lower efficiency. (I do just LOVE blowing manufacturer's claims out of the water...
)
Ohm's law says this:
14.4 X 1.21 = 17.5
1.21 X 1.21 = 1.46
So, according to Ohm's law, at 17.5 volts, those amplifiers CANNOT make more than 1.46 times their rated 14.4 volt power - less than 50% more... translating to less than 1dB gain... an increase that you will NEVER hear. Is it worth it to you now that it's all laid out? If it is, you, my friend, need to readjust your priorities! :)
-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: audiocableguy
Date Posted: March 20, 2009 at 12:12 AM
Posted By: i am an idiot
Date Posted: March 20, 2009 at 6:16 AM
Posted By: pumpkinman
Date Posted: March 20, 2009 at 12:00 PM