Alternator upgrade (is it the right choice).
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New member Username: InvictuzSeattle, Wa Usa Post Number: 7 Registered: Jan-05 | Question Where can i find a good HO alternator that requires little or no modification to stock electrical system (other than bigger cable or install bracket mounts). Based on info below is the bigger alternator the right solution? (from what i have read it appears to be but i find alot of conflicting info on +/- of more batteries, bigger caps, second alternators etc...) Problem I like it loud and hard all the time (i'm the guy pounding down the freeway at 6am, then quitely pulling into the garage at work, then pounding as soon as i hit i90 at 6pm). if i drop below about 1200RPM (25mph or lower) i watch my dash voltometer drop from about 13v to 10v. If i do not catch it my "check battery" light comes on at 9v and some times stalls the truck (even if still driving under 10mph). hard notes (outcast/speakerbox track 1, any Baby Anne or Q/Uberzone) on highway (at 2200rpm+) and i still see the needle sway. Goal I am trying to locate an 200+ amp (ideally 300) alternator for under 350$ that i can install (= basic cable replacement / minor bracket install, nothing more difficult than the self install of the below equipment...). Vehicle/current config: 1997 Jeep Grand Cherokee w/5.2liter 120 amp alternator (already upgraded from stock 90amp) Alpine 9833 control unit w/3 4 volt pair of outs Biggest battery i found at Schucks (not optima) 4X RF 301m 4X MTX81044a DVC (one 301m per MTX) 2X JVC AX4750 (powers infinitys) 4X 6000CS Infinity (each door) 2X 1001T Infinity 4X .5 farad caps (one for each 301m) 4 way Distribution/fuse block (aka MTX DIST) 2 way Distribution/fuse block (aka JVC DIST) 8g running from battery to MTX DIST (17 feet) 8g running from MTX DIST to JVC DIST (1.5 inches) 10g running from MTX DIST channel to each .5 farad 12g running from JVC DIST channel to each JVC amp 10g running from each .5 farad to RF 301m 12g running from each 301m to each MTX Scalability researching a midbass/midrange solution for near future addition. adding two more MTX after if refine fiberglass skill (2X MTX means 2X RF 301m's) possibly upgrading 301ms to P6001bd RF P6001bd Closing ok...think that covers it...any suggestions/advice/links are greatly appreciated! thanks |
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Gold Member Username: CarguyPost Number: 1385 Registered: Nov-04 | Okay, you are wasting lot of power by having so many amps. Every amp you install, it'll waste "x" amount of current. Let's say on idle, each amp uses up 2A. So 6 x 2 = 12A of lost power! That may not sound much, but sometimes 12A of current could make or break your alternator and electrical system. Have you though of getting 1 higher powered amp for your 4 subs and 1 4 channel amp for the components? Makes it lot easier and cleaner to install. If you get 1 1200W rms amp, then each sub will get 300W rms. Same thing you're getting with 4 amps but it'll waste less energy. JVC doesn't make good amps at all. You should've stuck with RF instead. As for your alternator, get a 2nd one for your car and send that in to be re-wired to 4alterstart.com. That will be the easiest since it will fit right in without any modification except for thicker alternator wire etc. I think they can re-build you 200A+, it'll all depend on cash. You own an American make so the HO alternator should be cheaper than import. |
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Bronze Member Username: Rob315Cuse, NY U.S. Post Number: 78 Registered: Jan-05 | www.4alterstart.com....you dont need a 300 amp alt. though find one around 200 or so, and you should be good. |
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Bronze Member Username: InvictuzSeattle, Wa Usa Post Number: 11 Registered: Jan-05 | Isaac: i went with the 4 seperate amps to ensure each sub has dedicated power rather than share the same power source among all 4 (and 6 soon). This was a bottleneck prevention step that actually just moved the bottleneck futher down the power line. Was i incorrect in thinking that seperate amps for each sub with a clean constant supply of power has no benefit over a single amp with the same power feed but having 4 subs relying on its output simultaneously (especially during hard/deep notes). i am considering removing the .5 farads as i can detect a difference in long bass notes after the first second or so...not sure if solid "quick" bass is worth the barely audible (i can hear it but friends i demo the problem too cannot) difference from beginning to end of longer notes. In researching i could not get a definitive answer from anyone with experience so i based my decision on what little i know regarding amps/wattage/voltage. During the initial install i upgraded the stock alternator from 90 to 120 but this turns out to be insufficient. i knew going in that JVC makes subpar amps and plan to upgrade them with my midbass expansion. i got such a great deal (i know: you get what you pay for...) so i bought 2 for one pair of components). Red/Isaac: Thanks for your quick response and the link...checking it out now. any and all suggestions are appreciated! |
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Gold Member Username: CarguyPost Number: 1393 Registered: Nov-04 | The only benefit I can think of having 4 separate amps is that maybe if one die, you still have 3 more. Other than that, there is no difference. A true 1200W rms amp will give same power as 4 300 rms amp. The reason why you see some people with multi amp is to separate bass, mids, and highs. Each get powered by an amp of their own. I know where you can use JVC amps, to power your mids. Highs and lows need a great amp to reproduce the original sound as close as possible without distorion. Since you already paid for .5F capacitors, you might as well use it. It's better than nothing. If however, you do get 1 1200W rms amp, then get 2.5F capacitor. It made a difference in my system. I used to get bass that was dropping off slightly, but now it's solid. Remember, capacitors recharge and discharge at a much faster rate than a battery. |
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Bronze Member Username: InvictuzSeattle, Wa Usa Post Number: 13 Registered: Jan-05 | Isaac: Thanks again for the help! this was the first install for me and a learning experience. Over the last year i spent 6 months stacking speakers, cables, amps, and more cables in a closet. When no more would fit i spent 4 days solid installing it all. In the 6 months since i have filled that same closet with experiences, solutions, "lessons learned" and more ideas. Based on your advice and others i have drawn out a plan of action: first: upgrade cable second:install sound absorbtion material third:bigger alternator (i already have a reply from 4alterstart.com...205amp for 250$) fourth finish fiberglassing my garage/house/driveway/neighbors dog and build a 6 sub enclosure. fifth: install proper midbass sixth: upgrade components (including amps) seventh: enjoy with a twist of lemon d ;-) quick question Do you think 205amp is sufficient when cabled correctly? Thanks again...its responses like your that make these forums such a valuable tool! david |
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Gold Member Username: CarguyPost Number: 1399 Registered: Nov-04 | From the look of it, it sounds like you're trying to create a new "earth". According to bible, it took God 7 days and he rested on the 7th day. As for your alternator, 205A will cover approximately 1800W - 1900W of rms power. Anything over, and you'd be walking a tight rope. |
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Gold Member Username: Jonathan_fGA USA Post Number: 3162 Registered: May-04 | "Was i incorrect in thinking that seperate amps for each sub with a clean constant supply of power has no benefit over a single amp with the same power feed but having 4 subs relying on its output simultaneously (especially during hard/deep notes)." It depends on the impedance you're running those amps on. Having 4 subs depend on the power is no different than having 1 sub, as long as you have clean power. The subs don't know anything but what power comes to them, the amp is what determines if it will deliver clean power, and that depends on the impedance run and the power supplied to it. Apples to apples, if both amps are running the same impedance and putting out the same power, the single amp is actually more ideal. This is because you don't have to worry about differences in the gain setting between amps, you draw less current, you save a ton of space, and a ton on wiring. You also help the system out because you aren't grounding a huge number of amps to the vehicle chassis, reducing the chance for ground loops, and you generally have better options for protection (fuses) to a single amp. On the other hand, if you were to run those multiple amps at higher impedances, and compare it to a single amp that is running a much lower impedance, the multiple amps would have more headroom since you're not pushing them to the max. But, any well designed amplifier will have a power supply that is capable of delivering much, much more power than its RMS rating. If you have good amps you'll never strain the power supply at all as long as you're within it's limits, and most people can't tell the difference in SQ between different load impedances if it's a good amp, especially on subwoofers. That's why Class D amps are so popular, they have much higher distortion, but it's hard to pick up on lower frequencies. In your case, you're pushing every single one of those amps to it's maximum impedance capability, so really you gain no benefit over having a single amplifier that put out more power. IMO you would have been better off getting a single amp that is capable of putting out more power, since you have 4 dual 4 ohm subs, you could have wired the subwoofer voice coils all in series, and then run them parallel to the amp for a final 2 ohm load. A JBL 1200.1 would have done the job and been considerably cheaper than those 4 amps, and of the same quality. |
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Bronze Member Username: InvictuzSeattle, Wa Usa Post Number: 15 Registered: Jan-05 | Jonathan: Good info! I should have mentioned i have each MTX80144 DVC wired for 2ohm (i personally verified each wiring configuration on each sub before i placed then in the sealed box. Each actually presented closer to a 2.2ohm impedance). While initially i thought the single amp (thus indvidual power supply) per sub was ideal but it has slowly dawned on me that it may not be so... A combination of the great feedback today from you, Isaac and others as well as personal experience with the gain matching, excessive wiring and massive power draw has prompted me to reevaluate my amplifier setup. Quick question: Does the single larger amp still draw similar amps as the multiple smaller amps if watt output is the same? Thank you again for you reply! i am going to start another thread for general opinions on multiple smaller amps versus a single larger amp with everything else equal. i am interested in hearing experiences of others who started with one configuration then changed. |
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Gold Member Username: Jonathan_fGA USA Post Number: 3168 Registered: May-04 | The single larger amp typically won't draw as much current simply because you're only dealing with one power supply opposed to 4 different ones in your case. The power supply of an amp is what draws the most current, and is typically what causes inefficiency of the amp due to heat. The transistors inside an amplifier have an internal voltage (typically .7 volts for silicon doped transistors) that has to be overcome before it allows current to pass and thus be amplified. To combat this, the amp will supply a bias voltage in order to keep the transistor "on" so that it will quickly react to the signal. This draws current even with no signal applied. Amplifiers are only so efficient, when you integrate circuitry into a single smaller chassis, typically you'll get more efficiency compared to multiple amps since you'd have a set amount of power that is applied in a small space with less internal resistance between components and also fewer components to do the job. |
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Bronze Member Username: InvictuzSeattle, Wa Usa Post Number: 16 Registered: Jan-05 | Jonathan: i wish i encountered you before i installed everything! thanks for your educational answers...can i get one more? Two scenarios common configuration; 300amp alternator 0 gauge and all other optimal cabling 2ohm load per individual DVC sub 4 X10" subs in sealed box cool air blown on amps steady supply of 13.8 volts to 1200 watt audio system scenario one one 1200 watt amp pushing all four subs. Deep, long bass note hits While all four subs will share the 1200 watts evenly the amp must produce that power from a single power source as it is a single amp scenario two four 300 watt amps (for a total of the same 1200 watts). One amp per DVC 10". Deep, long bass note hits All four subs get a total of 1200 watts (300 each). Each subs wattage is produced by a dedicated amp thus a dedicated power supply. My last remaining questions is: In extreme bass situations if all is equal and optimally configured is it better to have a single amplifier (and its single power supply) responsible for driving all 1200 watts and 4 subs or is it better to have that 1200 watt duty divided among four amps (and four power supplies); one dedicated to each sub? Thank you for you knowledgeable input! i have learned a lot today. |
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Bronze Member Username: InvictuzSeattle, Wa Usa Post Number: 17 Registered: Jan-05 | bass-end of project codename: Sloppy Joe  To replace or not to replace; that is the question! |
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Bronze Member Username: VaioPost Number: 26 Registered: Dec-04 | Hey your sound very cool INVICTUZ can you get some more pictures for us Thanks |
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Gold Member Username: Jonathan_fGA USA Post Number: 3170 Registered: May-04 | The 1200 watt amp will be required to produce 1200 at one time, as the 300 watt amps will be required to produce 300 each, all at one time. So you're pushing both to the maximum, dedicated power supplies offer no benefit when both are capable of the same power. If you have a lack of current due to the charging system, both scenarios will strain, but the scenario with multiple amps will strain even more since they draw more current. The 1200 watt amp would have less trouble getting said power because it draws less overall current than the 4 300 watt amps. Regardless on how many subs you have, as long as you have an impedance that is within the amp's capabilities and the power delivered to the amp, it will have absolutely no problem delivering it's amount of power, even on long bass notes. If you have charging system problems, either amp will struggle to produce their rated power, regardless of having a dedicated power supply. The dedicated amps offer no benefit in that area, since they draw more current, they make your charging system problems worse. |
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Bronze Member Username: InvictuzSeattle, Wa Usa Post Number: 18 Registered: Jan-05 | Thanks...i am convinced. Can you recommend a single large amp? With four DVC 10's @ 2ohm i have an RMS of 1600w (max of 3200w) I want an amp that i can add two more DVC 10s. So in the end i need an amp that can feed 2400w RMS (4800w max) That is the ideal amp. However i am only pushing each sub at 300w now so i could go as low as an amp only handling an RMS of 1800w for 6 subs. Any thoughts on these amps: Orion 2500D Orion XTreme Pro 2400 Rockford Fosgate T2000bd Rockford Fosgate T3000bd |
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Gold Member Username: CarguyPost Number: 1404 Registered: Nov-04 | If you have the money, look at Zapco, Arc Audio, US Amps. Before you buy RF, look at the above brands. |
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