Hey all! I just read the article "Alternators and Charging Systems" and learned a lot about this question but I need a bit more clarification. In my car I have an old Punch 75 running a set of 6.5 JBL's as well as two old Alpine 12's in series in a sealed box. I've been running it this way for like 10 years now with no issues. To trouble shoot a friend's subs I unplugged mine and put his in my trunk. His are Punch 1 series 10's in a sealed box being powered by a Kenwood KAC 7201 so I've essentially got my Punch 75 powering the JBL 6.5's and now have added a second amp running his 10's. The issue that I've run into is that my head lights are dimming with the beat of the subs. I don't have to do the math to know that my electrical system is being taxed. Part of the problem may be that he has his subs wired in parallel (2 ohm at the amp) which I don't think that amp can handle. So my question is this; if I wire his subs in series (scratch that, "when" I wire them in series) will that eliminate the pull on my electrical system that is causing my lights to dim?
Thanks!
Replies (11)
cplkittle on 01/17/2007 01:24:06
It will definitely reduce the pull on your electrical system, but hand in hand, it will reduce the output as well. If these subs are 4 ohm wired in parallel to 2, and you are going to wire them in series (8ohm) The output will only be 25% of what it was. Each time you double the load, the output drops by half.
This amplifier is not 2 ohm stable when bridged. A better bet would be to connect the subs one to each channel. This would be a better match in ohms.
Even so, you still may encounter dimming lights. Since you read the article, I won't preach to you about how to fix it. I will tell you that a deep cycle battery (like optima) will help out alot. It beats the crap out of capacitors, and stands up alot better to weather and deep discharges than a standard wet cell car battery.
jrwsound on 01/17/2007 05:00:44
I appreciate your help. I will go with the stereo wiring option then and look into the possibility of an additional battery after that.
swez on 01/17/2007 09:48:55
Not an additional battery here.... one strong battery is a better option as a 2nd battery, (Aux) will drag the ALT down even more.
Also, this car is likely to have a pretty modest ALT. (85 amperes at >2,000 RPM) At idle speeds, we generally get about 50% of that. Here, we have a few options:
1. Big 3 upgrade
2. Smaller pully diameter off the ALT
3. Upgrade the ALT to higher output capacity (120-150 Amperes)
Swez
jrwsound on 01/17/2007 14:15:04
Thanks for clarifying that for me Swez. On my way out of work this morning a co-worker corrected me on the battery upgrade instead of add-on as well. :-)
That article sure was helpful though. I think I'll go back through it and do the math on my system just to hammer the point home. One more question though; the article says to divide RMS but how do you know what to use for this figure on an under rated amp (like my punch 75)?
cplkittle on 01/17/2007 14:47:35
On a block of gold like that punch 75, just take the fuse rating and multiply by 13.8 (the avreage charging voltage of your vehicle)
This will give you a number close to peak power output. Now, Mathematically RMS is 70% of peak power. (at the lowest stable impedence)
Newer amplifiers consider RMS to be 50%. That is why you see 500w RMS/1000w peak rated amps. True power amplifiers will give RMS only, but you can expect to pay 60cents or more per watt for these. You will also find 2,000w amplifiers with 2x25amp fuses (50a X 13.8v=690w). So it is confusing to say the least. Good question though.
jrwsound on 01/17/2007 15:17:52
Thanks!
natty24 on 01/17/2007 20:20:11
hey guys, is the JL e188d a good amp?
natty24 on 01/17/2007 20:20:52
e1800d
natty24 on 01/17/2007 20:24:51
I have a n e1800d amp with 2 w3v3's with a 6 farad cap reading 14:99 voltage and it still cuts off, could it be the car?
cplkittle on 01/17/2007 22:46:05
JL is a good brand of products.
What exactly do you mean cuts off? Does the audio cut off, or does the radio, the car?
swez on 01/17/2007 23:06:39
What is the exact model number pf your subs and which coil set do they have? (Dual 2 ohms, Dual 4's or Dual 6 ohm versions) This matters a lot and how they are wired to this amp as well.
Does you amp protection light come on when the subs stop playing too?
Swez
Thanks!
Replies (11)
cplkittle on 01/17/2007 01:24:06
It will definitely reduce the pull on your electrical system, but hand in hand, it will reduce the output as well. If these subs are 4 ohm wired in parallel to 2, and you are going to wire them in series (8ohm) The output will only be 25% of what it was. Each time you double the load, the output drops by half.
This amplifier is not 2 ohm stable when bridged. A better bet would be to connect the subs one to each channel. This would be a better match in ohms.
Even so, you still may encounter dimming lights. Since you read the article, I won't preach to you about how to fix it. I will tell you that a deep cycle battery (like optima) will help out alot. It beats the crap out of capacitors, and stands up alot better to weather and deep discharges than a standard wet cell car battery.
jrwsound on 01/17/2007 05:00:44
I appreciate your help. I will go with the stereo wiring option then and look into the possibility of an additional battery after that.
swez on 01/17/2007 09:48:55
Not an additional battery here.... one strong battery is a better option as a 2nd battery, (Aux) will drag the ALT down even more.
Also, this car is likely to have a pretty modest ALT. (85 amperes at >2,000 RPM) At idle speeds, we generally get about 50% of that. Here, we have a few options:
1. Big 3 upgrade
2. Smaller pully diameter off the ALT
3. Upgrade the ALT to higher output capacity (120-150 Amperes)
Swez
jrwsound on 01/17/2007 14:15:04
Thanks for clarifying that for me Swez. On my way out of work this morning a co-worker corrected me on the battery upgrade instead of add-on as well. :-)
That article sure was helpful though. I think I'll go back through it and do the math on my system just to hammer the point home. One more question though; the article says to divide RMS but how do you know what to use for this figure on an under rated amp (like my punch 75)?
cplkittle on 01/17/2007 14:47:35
On a block of gold like that punch 75, just take the fuse rating and multiply by 13.8 (the avreage charging voltage of your vehicle)
This will give you a number close to peak power output. Now, Mathematically RMS is 70% of peak power. (at the lowest stable impedence)
Newer amplifiers consider RMS to be 50%. That is why you see 500w RMS/1000w peak rated amps. True power amplifiers will give RMS only, but you can expect to pay 60cents or more per watt for these. You will also find 2,000w amplifiers with 2x25amp fuses (50a X 13.8v=690w). So it is confusing to say the least. Good question though.
jrwsound on 01/17/2007 15:17:52
Thanks!
natty24 on 01/17/2007 20:20:11
hey guys, is the JL e188d a good amp?
natty24 on 01/17/2007 20:20:52
e1800d
natty24 on 01/17/2007 20:24:51
I have a n e1800d amp with 2 w3v3's with a 6 farad cap reading 14:99 voltage and it still cuts off, could it be the car?
cplkittle on 01/17/2007 22:46:05
JL is a good brand of products.
What exactly do you mean cuts off? Does the audio cut off, or does the radio, the car?
swez on 01/17/2007 23:06:39
What is the exact model number pf your subs and which coil set do they have? (Dual 2 ohms, Dual 4's or Dual 6 ohm versions) This matters a lot and how they are wired to this amp as well.
Does you amp protection light come on when the subs stop playing too?
Swez
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