Hey everyone how’s it going, it’s been awhile since I’ve posted on CK.
Just a quick simple question, I am currently thinking about getting a new amp to replace my used JBL 300.1 to power my 12” Alpine SWR-1241D. At first I was thinking about getting the Alpine MRD-M301 but then I found a really good deal on the MRD-M501 for $229.
What my question is, is if I were to used the MRD-M501 but had the gains set to a lower setting to reduce the chance of ruining my sub it would also draw less current right? I know that my stock electrical system wouldn’t be able to support the 60amps that M501 will pull at max volume, but having it set lower to power my 300wrms 12” type r sub would not draw as much current, is this correct?
The only reasons why I am thinking about getting the bigger amp is because when I get my new car I getting a JL 10W7 or 12W6v2. So I’m planning for future upgrades that I know are coming and the MRD-M501 would be a great match for either of those subs mentioned.
Thanks,
Jay
Replies (4)
LC1 on 02/1/2005 22:03:01
Oh yah, my sub is 4+4DVC and I will be running it @2 Ohms.
UKinstaller on 02/1/2005 22:33:52
you should be fine. i've run two M301's at the same time with little if any noticeable electrical issues. the M501 shouldn't give you any problems.
-UK
P0werLifter on 02/1/2005 22:48:30
To answer your question, You'd be better off getting the MRD-M501 amplifier. Maybe subwoofers can handle power beyond their RMS rating as long as its clean NON clipped power (distorted).
Infact if you want to correctly tune your amplifier ive got some calculations for ya
1st thing is you'll need a calculater and Muti-meter.
______________________________________________________
Now lets get to the fun:
A. Set the volume @ 3/4 of maximum
-Turn off all EQ's/presets in the headunit
B. Disconnect speakers from amplifier
P = Power In watts
I = Current In amperes
R = Resistance in ohms (the nominal impendence)
V = Potential in volts
Knowns
Resistance (the nominal resistance of your speakers)
Power (desired wattage)
Unknowns
Voltage (we'll measure this)
Current
Formulas
P = I*V [formula for power]
V = I*R [Ohms Law]
After a lil subsitution to get voltage in terms of power and resistance we get
V = Square Root(P*R)
For example lets say you want to run 200watts @ 2 ohm load to an amplfier. Then you'd plug in the numbers as follows
Sqr Rt(200*2) = 20Volts.
Another example lets say you have 150watts @ 4ohms
Sqr Rt(150*4) = 24.49volts
This means all you have to do is raise the gain till you read 24.49volts AC on the speaker outputs of your amplifier if you were using the 150watts @ 4ohm.
As a source, use a Sign Wave recorded at 0dB within the frequency range you desire to amplify. (lets say for your subwoofers, you'd need a Bass Test CD with a sign wave section and you'd use per say a 50hz test tone while you adjust your gains)
Hope that helps
Victor on 02/2/2005 00:37:32
Well versed with ohms law .. eh..!!
Just a quick simple question, I am currently thinking about getting a new amp to replace my used JBL 300.1 to power my 12” Alpine SWR-1241D. At first I was thinking about getting the Alpine MRD-M301 but then I found a really good deal on the MRD-M501 for $229.
What my question is, is if I were to used the MRD-M501 but had the gains set to a lower setting to reduce the chance of ruining my sub it would also draw less current right? I know that my stock electrical system wouldn’t be able to support the 60amps that M501 will pull at max volume, but having it set lower to power my 300wrms 12” type r sub would not draw as much current, is this correct?
The only reasons why I am thinking about getting the bigger amp is because when I get my new car I getting a JL 10W7 or 12W6v2. So I’m planning for future upgrades that I know are coming and the MRD-M501 would be a great match for either of those subs mentioned.
Thanks,
Jay
Replies (4)
LC1 on 02/1/2005 22:03:01
Oh yah, my sub is 4+4DVC and I will be running it @2 Ohms.
UKinstaller on 02/1/2005 22:33:52
you should be fine. i've run two M301's at the same time with little if any noticeable electrical issues. the M501 shouldn't give you any problems.
-UK
P0werLifter on 02/1/2005 22:48:30
To answer your question, You'd be better off getting the MRD-M501 amplifier. Maybe subwoofers can handle power beyond their RMS rating as long as its clean NON clipped power (distorted).
Infact if you want to correctly tune your amplifier ive got some calculations for ya
1st thing is you'll need a calculater and Muti-meter.
______________________________________________________
Now lets get to the fun:
A. Set the volume @ 3/4 of maximum
-Turn off all EQ's/presets in the headunit
B. Disconnect speakers from amplifier
P = Power In watts
I = Current In amperes
R = Resistance in ohms (the nominal impendence)
V = Potential in volts
Knowns
Resistance (the nominal resistance of your speakers)
Power (desired wattage)
Unknowns
Voltage (we'll measure this)
Current
Formulas
P = I*V [formula for power]
V = I*R [Ohms Law]
After a lil subsitution to get voltage in terms of power and resistance we get
V = Square Root(P*R)
For example lets say you want to run 200watts @ 2 ohm load to an amplfier. Then you'd plug in the numbers as follows
Sqr Rt(200*2) = 20Volts.
Another example lets say you have 150watts @ 4ohms
Sqr Rt(150*4) = 24.49volts
This means all you have to do is raise the gain till you read 24.49volts AC on the speaker outputs of your amplifier if you were using the 150watts @ 4ohm.
As a source, use a Sign Wave recorded at 0dB within the frequency range you desire to amplify. (lets say for your subwoofers, you'd need a Bass Test CD with a sign wave section and you'd use per say a 50hz test tone while you adjust your gains)
Hope that helps
Victor on 02/2/2005 00:37:32
Well versed with ohms law .. eh..!!
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