I have a 2000 jetta with this so far installed:
60.5cs infinity kappa components (stock amplification)
2 12's infinity kappa se (running off mtx 4320 bridged 280x2)
when I started piecing together my system I wanted 2 sets of
components running off 75x4 and my subs how they currently
are. as it is my electrical system is pretty taxed with just one
amp. im afraid if I add another amp as planned I will need to
upgrade alt and battery which I really dont want to do.
if i went with a jbl gto 755.6 which would give 60x4 and 300x1
would I still need to upgrade alt?
thanks and sorry for being long winded
Replies (10)
swez on 09/15/2004 17:24:49
One effective way around this problem is to use a reasonably potent 4 channel amp. We have been getting some good reports of folks running the front channels to front speakers and rears off the HU amps.
The subs are powered by the rear channels of the 4 channel amp and are normally adequate as rear fill w/o amping. Why, rear deck mounted speakers, are usually louder than front door mounted speakers. We often pick up a few extra dB of sound in the rear speakers due to location and mounting. The fronts being amped, will be dominate, while the rears will be there... just a tad softer.
These subs you have now, are they the 4 ohm single coil jobs or DVC's? Depending on your answer, there are a few solutions we can suggest.
That JBL amp mentioned has a max current draw of 87 amperes. To get the most for this amp, you'd need about 140-150A of ALT power to drive it and all your vehicle features too. Would think your present ALT is about 100A tops. So any amp that draws more than ~40-50A of power, will overload your electrical system.
Installing a high CCA rated BAT and upgrading the power wires frm ALT/BAT, BAT/GND and doubling grounding strap will help move power more efficiently and add a decent current reserve to the system in general. Most smaller cars have a 500-600 CCA rated BAT as stock. Upgrading to a BAT w/ say 850 (or more) CCA will help, along with wiring upgrades.
Comments?
Swez
aalvarez on 09/15/2004 17:32:35
my subs are the 4 ohm single jobs...my rear speakers are located in the doors not the rear deck...will this make a big difference?
swez on 09/15/2004 18:13:45
Hard to say.... most likely, the door mounts in front and rear are going to sound pretty much the same. But, the fact that these are just rear fill... a few dB less from the back speakers is usually acceptable to most folks. Can still use the HU amps if you wish to save power for your front stage and subs.
That MTX amp demands a lot of current when used in bass applications. But if used for full range speakers, it can be set up to provide plenty of power to 2 or all 4 door speakers, but not draw so much current in the process. The only drawback... will lose fade control on F&R speakers this way.
Tough call here friend... balancing the system and not overtaxing your electricals usually means dialing back on SPL demand from any amps used. The best way I see at the moment, would be to check out Avionixx 4 channel amps. These are Class T amps and do well for full range and bass. I think they have ~125 x 4 (RMS) amp that may do well in your application. Here's a link to preview what you get.
http://www.avionixxusa.com/ep/axt_8004.htm
The only concern I have here... not sure how much current this amp will draw when you crank up the bass. One way to limit current draw, is to fuse the amp power line at 40-60A. If the amp tries to pull more than that, the fuse will blow in a few seconds.
Can always contact them via Tech Service and ask how much current this amp will consume at full power. My guess... about 80A.
http://www.avionixxusa.com/ep/contact.htm
Swez
uochronos on 09/15/2004 18:50:14
also if front off amp and rear off HU does not sound ok. you can wire front and rear left together in parrelel and hook to one channel and do same for right. this wellg ive all spakers equal power but you wont be able to fade front and rear.
if you really want to get little less power in the rear then front with this set up. you can get a resistor of proper size and specs and hook to rear speakers to get less power to them..
hope this helps
Chronos
aalvarez on 09/15/2004 19:06:14
thanks for the quick response swez...I think I am going to go with one sub and have the fronts amplified and the rears running off the HU..would you recommend getting the avionixx amp instead of keeping the mtx? thanks for all the help
uochronos on 09/15/2004 19:16:44
that avionixx amp can really pull the power. i belive if i recall right they recommend a 100amp fuse for it.
they have a 600.4 and a 440.4 though that are great amps that pull a bit less power i belive 100x4 and 80x4... the 440.4 can be had on ebay for 149.99$ brand new.
the 800.4 well work and to keep it from pulling full power you can fuse it at 60amps and just set the gain so the fuse does not blow.
Chronos
swez on 09/16/2004 07:02:03
I like the the 800.4 as it is a Class T amp. These are much more efficient with power than most common mosfet (Class A/B) amps.
The other amps mentioned by Chronos are smaller, but these are High Current amps that deliver less efficiency and still pull large current values as well.
If you call Avionixx, (or e-mail them) they can tell you max current draw numbers on the amps of interest.
Swez
PS Do you know the amp rating of your present ALT? Can find out from a dealer or a good autoparts tech at Autozone, Pepboys or NAPA. If you live in a larger urban area, there may be a few ALT rebuilders in your area that can tweak the present ALT to net more output. Depends on the case size and components available for same.
aalvarez on 09/16/2004 18:08:59
thanks for the lead on the class T amps. I will definatley pick up the 800.4 and run the fronts and one sub off of it. If im not satisfied with the bass I was thinking of getting rid of the more power hungry kappas and getting 2 12 jl w0's rated at 125 rms each. oh yeah will also get a new battery and upgrade big 3. any suggestions on a battery?
P0werLifter on 09/16/2004 18:14:42
Optima batteries are good to start with (yellow and red top Deep Cycle) for good CCA...Stinger makes some awesome batteries for car audio but their very expensive. Their are some other ones but I cant quite remember the names.
-Jason
swez on 09/16/2004 19:07:05
Optima Gel Cells are very popular with Audio buffs. They are a tad expensive and if you are trying to conserve expenses, Interstate, DieHard and other brands will do a good job w/o all the glitz and price. May have to modify the battery tray to fit a larger CCA BAT in that slot too.
Also, if you live in a cold winter climate, use the normal engine starting battery. They deliver more cranking power to cold engines than the common Deep Cycle BAT's. But if you live in mild winter climates, the Deep Cycle (marine style) BAT is a good option as they can take many deep discharge cycles w/o premature failure common to common lead-acid BAT's.
Swez
60.5cs infinity kappa components (stock amplification)
2 12's infinity kappa se (running off mtx 4320 bridged 280x2)
when I started piecing together my system I wanted 2 sets of
components running off 75x4 and my subs how they currently
are. as it is my electrical system is pretty taxed with just one
amp. im afraid if I add another amp as planned I will need to
upgrade alt and battery which I really dont want to do.
if i went with a jbl gto 755.6 which would give 60x4 and 300x1
would I still need to upgrade alt?
thanks and sorry for being long winded
Replies (10)
swez on 09/15/2004 17:24:49
One effective way around this problem is to use a reasonably potent 4 channel amp. We have been getting some good reports of folks running the front channels to front speakers and rears off the HU amps.
The subs are powered by the rear channels of the 4 channel amp and are normally adequate as rear fill w/o amping. Why, rear deck mounted speakers, are usually louder than front door mounted speakers. We often pick up a few extra dB of sound in the rear speakers due to location and mounting. The fronts being amped, will be dominate, while the rears will be there... just a tad softer.
These subs you have now, are they the 4 ohm single coil jobs or DVC's? Depending on your answer, there are a few solutions we can suggest.
That JBL amp mentioned has a max current draw of 87 amperes. To get the most for this amp, you'd need about 140-150A of ALT power to drive it and all your vehicle features too. Would think your present ALT is about 100A tops. So any amp that draws more than ~40-50A of power, will overload your electrical system.
Installing a high CCA rated BAT and upgrading the power wires frm ALT/BAT, BAT/GND and doubling grounding strap will help move power more efficiently and add a decent current reserve to the system in general. Most smaller cars have a 500-600 CCA rated BAT as stock. Upgrading to a BAT w/ say 850 (or more) CCA will help, along with wiring upgrades.
Comments?
Swez
aalvarez on 09/15/2004 17:32:35
my subs are the 4 ohm single jobs...my rear speakers are located in the doors not the rear deck...will this make a big difference?
swez on 09/15/2004 18:13:45
Hard to say.... most likely, the door mounts in front and rear are going to sound pretty much the same. But, the fact that these are just rear fill... a few dB less from the back speakers is usually acceptable to most folks. Can still use the HU amps if you wish to save power for your front stage and subs.
That MTX amp demands a lot of current when used in bass applications. But if used for full range speakers, it can be set up to provide plenty of power to 2 or all 4 door speakers, but not draw so much current in the process. The only drawback... will lose fade control on F&R speakers this way.
Tough call here friend... balancing the system and not overtaxing your electricals usually means dialing back on SPL demand from any amps used. The best way I see at the moment, would be to check out Avionixx 4 channel amps. These are Class T amps and do well for full range and bass. I think they have ~125 x 4 (RMS) amp that may do well in your application. Here's a link to preview what you get.
http://www.avionixxusa.com/ep/axt_8004.htm
The only concern I have here... not sure how much current this amp will draw when you crank up the bass. One way to limit current draw, is to fuse the amp power line at 40-60A. If the amp tries to pull more than that, the fuse will blow in a few seconds.
Can always contact them via Tech Service and ask how much current this amp will consume at full power. My guess... about 80A.
http://www.avionixxusa.com/ep/contact.htm
Swez
uochronos on 09/15/2004 18:50:14
also if front off amp and rear off HU does not sound ok. you can wire front and rear left together in parrelel and hook to one channel and do same for right. this wellg ive all spakers equal power but you wont be able to fade front and rear.
if you really want to get little less power in the rear then front with this set up. you can get a resistor of proper size and specs and hook to rear speakers to get less power to them..
hope this helps
Chronos
aalvarez on 09/15/2004 19:06:14
thanks for the quick response swez...I think I am going to go with one sub and have the fronts amplified and the rears running off the HU..would you recommend getting the avionixx amp instead of keeping the mtx? thanks for all the help
uochronos on 09/15/2004 19:16:44
that avionixx amp can really pull the power. i belive if i recall right they recommend a 100amp fuse for it.
they have a 600.4 and a 440.4 though that are great amps that pull a bit less power i belive 100x4 and 80x4... the 440.4 can be had on ebay for 149.99$ brand new.
the 800.4 well work and to keep it from pulling full power you can fuse it at 60amps and just set the gain so the fuse does not blow.
Chronos
swez on 09/16/2004 07:02:03
I like the the 800.4 as it is a Class T amp. These are much more efficient with power than most common mosfet (Class A/B) amps.
The other amps mentioned by Chronos are smaller, but these are High Current amps that deliver less efficiency and still pull large current values as well.
If you call Avionixx, (or e-mail them) they can tell you max current draw numbers on the amps of interest.
Swez
PS Do you know the amp rating of your present ALT? Can find out from a dealer or a good autoparts tech at Autozone, Pepboys or NAPA. If you live in a larger urban area, there may be a few ALT rebuilders in your area that can tweak the present ALT to net more output. Depends on the case size and components available for same.
aalvarez on 09/16/2004 18:08:59
thanks for the lead on the class T amps. I will definatley pick up the 800.4 and run the fronts and one sub off of it. If im not satisfied with the bass I was thinking of getting rid of the more power hungry kappas and getting 2 12 jl w0's rated at 125 rms each. oh yeah will also get a new battery and upgrade big 3. any suggestions on a battery?
P0werLifter on 09/16/2004 18:14:42
Optima batteries are good to start with (yellow and red top Deep Cycle) for good CCA...Stinger makes some awesome batteries for car audio but their very expensive. Their are some other ones but I cant quite remember the names.
-Jason
swez on 09/16/2004 19:07:05
Optima Gel Cells are very popular with Audio buffs. They are a tad expensive and if you are trying to conserve expenses, Interstate, DieHard and other brands will do a good job w/o all the glitz and price. May have to modify the battery tray to fit a larger CCA BAT in that slot too.
Also, if you live in a cold winter climate, use the normal engine starting battery. They deliver more cranking power to cold engines than the common Deep Cycle BAT's. But if you live in mild winter climates, the Deep Cycle (marine style) BAT is a good option as they can take many deep discharge cycles w/o premature failure common to common lead-acid BAT's.
Swez
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