need new wire?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=13585
Printed Date: May 12, 2024 at 11:55 AM
Topic: need new wire?
Posted By: alienated
Subject: need new wire?
Date Posted: May 15, 2003 at 11:50 PM
i have a 8guage running to my amp, which is a 12v 300w mono alpine amp. it's running to a apline type r cranking at 300w @ 1 ohm. anyways, it cuts out when i turn it up, so im thinking i just need to go with a 4 guage and be happy. it's also plugged into a .5 farad capacitor. any suggestions?
Replies:
Posted By: completeaudio
Date Posted: May 15, 2003 at 11:58 PM
have you measured for voltage drop? Does the amp protect light come on or thermal overload? Is the amp extreamly hot? Does the sound cut out right away or after some time?
Posted By: wvsquirrel
Date Posted: May 16, 2003 at 12:31 AM
Assuming you're asking about the V12 MRD-M300...
I've been wrong on this before, but no where on the Alpine site or in the manual does it say that the V12 MRD-M300 is stable at 1ohm. I'm assuming by your description that you are using one 2ohm Type R DVC to get the 1ohm load.
Look on page 18 of your manual for some additional troubleshooting since it has a built in display for that purpose.
Upgrading the wire would be a good start since 8AWG is the minimum gauge that alpine recommends for that amp.
Turn down the gains if the 1ohm load is putting the amp into protect mode.
Unless you upgraded your cars electrical system to 14.4volts I don't think you're quite "cranking at 300w". I hate to be the one to break the news, but on a 12volt system your amp is rated at 200 x 1 @ 2ohms (page 20 of the manual) (like I said earlier Alpine doesn't rate that amp at a 1ohm stable load). Most people don't realize the "Fine Print" on the spec sheets, boxes, or internet blurbs that show the power ratings based on a 14.4volt system, not 12volt. You usually have to look in the manual to find the 12volt specs if it doesn't specifically say "12volt" anywhere else. It's a cheap trick the manufacturer's do to make people think they're getting a great deal (when if fact you're usually losing 50-100 watts). ------------- Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
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Posted By: auex
Date Posted: May 16, 2003 at 4:54 PM
Like Squirrel said, Alpine does not make an amp that is stable to 1 ohm. Either wire you sub differently or get an amp that is stable at one ohm.
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Posted By: alienated
Date Posted: May 20, 2003 at 7:50 PM
the way i have it setup is that the positive from the amp goes to both positives (dvc) on the sub. what other way can i wire it since it is only a mono amp? as for the other stuff, i'll figure that out when i get home today. thanks guys!
Posted By: wvsquirrel
Date Posted: May 20, 2003 at 9:14 PM
You're running what's called "independant wiring" to the DVC sub. It's usually not recommended (since the gains need to be damn near exact), but it's safer since you are using a mono amp with only 1 channel. However, you are still running in a parallel configuration which is producing the 1ohm load. Unfortunately you are only left with being able to run at 4ohms safely (unless you got another 2ohm DVC or a 1ohm stable amp). Your amp is rated 100 x 1 @ 4ohms. It's less power then you're getting now, but the amp will be stable.
Here's how to wire your sub at 4ohms to your current amp...
If you got another 2ohm DVC sub then you would wire them like this into your existing amp at 2ohms...
If you got a 1ohm stable amp, then the proper way to wire your existing sub into a 1ohm load is like this...
Your last option depends on if you can exchange the sub for the 4ohm DVC version (you never did mention what sub you are using). If you could do that, then you would wire it like this for a stable 2ohm load...
 ------------- Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
Posted By: alienated
Date Posted: May 21, 2003 at 9:30 PM
yeah, i had it wired at 4ohms and man did it sound crappy. i have another 300w amp, it's a Legacy though :-/ im wondering if i can just bridge it (since it's a 2 channel) and run that one to 1 voice coil, and then run the apline amp to the other voice coil. is that suggested at all?
Posted By: D148L0
Date Posted: May 21, 2003 at 10:21 PM
alienated, if you do that you are gonna ruin your sub... chec the 2 or 4 Ohm amp/8 Ohm Sub forum (2 up from this one) where you can find more info/links about it... ------------- D148L0
Posted By: wvsquirrel
Date Posted: May 21, 2003 at 10:26 PM
You'll tear that sub apart in a heartbeat if you use 2 different amps, 1 to each voice coil. It's not even recommended doing with 2 seperate channels of the same amp, let alone using 2 different amps.
Are any of my other suggestions above viable or possible for you to do/afford? ------------- Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
Posted By: alienated
Date Posted: May 23, 2003 at 1:25 PM
afford is the big problem. i just spent $1k on all this stuff. im just going to have to wait for a while to see what can happen. ill just run it at 4 ohms since i have a convertable and i have to turn it up really loud just to hear it when the top is off.
Posted By: alienated
Date Posted: May 23, 2003 at 1:44 PM
I juts re-wired it for the 4ohm load and i must say, it sounds even better now. That's a big relief because i thought that it would end up ruining it. squirrel, you mentioned about the amps and channels, then how do people wire dvc2ohm subs?
Posted By: wvsquirrel
Date Posted: May 23, 2003 at 9:37 PM
Either mono (1 channel) or bridged (combining 2 channels into 1). By doing this, all the voice coils receive the same input signal since the signal for 1 coil is comming from the same channel as the signal for the other coil. With a single 2ohm DVC you can wire into a 1 or 4 ohm total load (both of which I posted diagrams for earlier in this thread). 1ohm stable amps tend to be a little pricey. JBL makes the BP600.1 and the BP1200.1 which are great amps from what I've read, reasonably priced, and 1ohm stable. It all depends on what you can afford!
Instead of recommending a mono amp and a single 4ohm DVC sub wired into 2ohms, who ever sold you your equipment must have recommended the 2ohm DVC wired into 4ohms using a 2-channel amp (and probably told you that it was perfectly safe to use independant wiring).
If you want to see all the diferent wiring possibilities of 2 and 4 ohm DVC's, you can check out JL's Wiring Wizard or Rockford Fosgate's Wiring Wizard. ------------- Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
Posted By: alienated
Date Posted: May 26, 2003 at 6:25 PM
i actually got what my friend had in his car, and... i come to find out... sadly enough he was sold by the guys at circuit city. i, then went to crutchfield and did some "research" there and ended up getting the same thing. Being the person I am i rushed into it and just got the 2ohm dvc apline type r. i am thinking about sending it back because im still within my 30 days and just get the 4ohm version, but... i have it wired at 4ohms and it sounds just fine. i'd like to thank everyone in here who helped me out with this little "delema". I really appreciate the help and the replys are very educational. Once again... Thank you. -Michael
Posted By: wvsquirrel
Date Posted: May 26, 2003 at 11:41 PM
No prob, glad to help.
It would deffinately be to your benefit to exchange the type r for the 4ohm version since you're still within the 30-day period. Right now you're getting about 100 watts to the sub. If you went with the 4ohm DVC wired in parallel to the 2ohm total load then you can get at least 200 watts out of you amp instead  ------------- Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
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