Hi again I just traded my mtx sub for a mtx thunder 7402 amp i was wondering the best way to wire my 2 10in RF p3 dual 4 ohm subs. I was thinking to wire them to 1 ohm for the amp is that a good choice? thanks
steve
Replies (10)
trunkisloud on 09/13/2007 23:44:25
here are the specs on this amp....
A/B (Patented Pure N-Channel) (Pat. No: US05631608, US05783970)
Power Supply Semi Unregulated MOSFET (Pat. No: US05598325)
THD + Noise (1 Watt) 0.1%
Signal-To-Noise Ratio (1 Watt) 75 dB
Overload Protection
Thermal Protection
Xtant Technology Cooling Continuously Variable Fan Speed
Connection Terminals StreetWires Connectors
14.4VDC Power
4 Ohms 100 Watts RMS x 2
2 Ohms 200 Watts RMS x 2
1 Ohm 300 Watts RMS x 2
4 Ohms Bridged 400 Watts RMS
2 Ohms Bridged 600 Watts RMS
INPUT (RCA Connection) Low Level
Hi Level w/ Smart Engage (Pat. No: US06556683)
INPUT SWITCH Input Sense 100mV-1V/1V-10V
Stereo - 100mV-10V
CROSSOVER Hi,12dB / Low, 24dB Mono @ 40Hz-350Hz, Defeat x
Quasi Parametric: Boost/Cut +/-12dB, Freq. 30Hz-80Hz
ARC: Cut 0-15dB, Freq. 200Hz
OTHER FEATURES Remote Subwoofer Level Control Parallelable x
DIMENSIONS Length 9-5/8" Width 20-11/16" Height 2-1/2"
this amp is a bad match for these subs....as you can only get 1 or 4 ohms with the subs...with these subs you can bridge it a 4ohms and get about 200wrms to each sub..and if you run a 1ohm load you would only be able to use 1 channel of the amp at 300wrms....these subs are rated at 400wrms each......you would be underpowering a bit...a 1ohm stable class d monoblock would do nicely here....heres a link to the wiring potential of these subs.....it will help you get a better understanding of the works in relation to the amp
http://www.rockfordfosgate.com/rftech/woofer_wizard.asp?submitted=true&woofer_qty=2&woofer_imp=4
MagorksAudio on 09/14/2007 00:33:14
wouldnt the subs get 300 watts rms each at 1 ohm because the amp specs say each channel puts out 300 watts rms? the amp is 2 channels one sub for each channel right? doesnt it mean when it says 300 watts rms x2 that each channel puts out 300 watts rms at 1 ohm? im confused. because the RF wirring diagram says that each sub is wired to 1 ohm right?
Str8Bumpin25951 on 09/14/2007 02:20:32
Question, I just re-wired my subs and went to go hook them up and there were sparks an i blew all my fuses what happened Where did i go wrong?
trunkisloud on 09/14/2007 06:55:00
the subs are wired TOGETHER for one ohm....there will be only a negative and positive wire running to the amp because the subs are wired together..how can you use 2 channels with only one set of wires? get it now? theres no other way to get 1ohm with these subs...
str8- sounds like you shorted your power somewhere..thats strange if all you did was hooked up the subs.
swez on 09/14/2007 09:38:38
Mag, this amp is not the best choice for those subs. (As Trunk pointed out well) It will work, but each sub will get about 200 watts RMS, no matter how the subs are configured to this amp.
The safest way to use this combo, would be to bridge the amp to Mono bridged mode and wire the subs for a net 4 ohm load. This amp will deliver a solid 400 watts RMS @ 4 ohms and each sub gets ~200 watts. That's not all bad, but the subs can handle more power as they are not all that efficient to begin with. (83dB SPL @ 2.83 volts) These subs are power hungry and to get the most from them, more power from the amp is your best bet.
Swez
PS St8, would you mind starting a fresh post and give complete details on the amp and subs, (Mfg & model #'s) used and how the subs were wired to the amp? It does sound like a major mistake was made when rewiring these subs. With luck the amp was not damaged in the process. Say more in a new post.
MagorksAudio on 09/14/2007 12:47:20
thanks i understand now i just keep ging backwards when think im going forward thanks fr all the help guys this site is the best. im short on money right now but when i get some ill donate to the site thanks again swez and trunk!!!!!!: }
MagorksAudio on 09/14/2007 15:36:19
I hooked up the RF P3s to the 7402 and bridge it so the subs are getting 200 watts rms to each sub it bumps but its not load anough for me. I think im going to upgrade the amp what kind of amp should i get I was thinking of some sort of RF amp. If I get a RF amp what size should i get? thanks agian for the help
swez on 09/14/2007 16:23:21
This may seem counterintuitive, but if you can get your hands on a matching MTX amp and carefully set the gains to match, using one amp per sub is a good recovery option here. (2 ohms/amp in bridged mode)
The biggest drawback here, these amps are high on current draw and some additional electrical support for these amps would be in order. At full power, these amps can pull about 100A's. However, since you'll be dialing back the gains for a solid 400 RMS per sub, current draw will be more like 80A's for the pair.
If you went with an RF amp, the Punch P1000-1bd is a solid choice. It is 1 ohm stable and can deliver up to 1,000 watts RMS @ 1 ohm loads. This amp has a bit more power than the P3's are rated for, but some careful gain setting will compensate for this. This amp is a bit on the spendy side too. The MSRP is $650.00. Off e-bay, the going price is about $350.00 + S/H.
http://cgi.ebay.com/Rockford-Fosgate-p1000-1bd-PUNCH-mono-amp-MSRP-650_W0QQitemZ320156766427QQihZ011QQcategoryZ64570QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
THINK through your options carefully as this plan has a few sharp treble hooks in it. (Power management specifically)
Swez
MagorksAudio on 09/14/2007 16:42:15
Thanks for the help i think im going to get the RF P1000-1bd because i rather have 1 amp for the subs less wiring and wouldnt draw less power then having 2 of the tose mtx amps? and would 4 gauge power wire be a good choice for the RF amp? I was wondering if i should upgrade the mids and the highs or are the delco stock speakers good anough? the bass does not drown out the sound so im sure if i sould keep them in or not. thanks again
swez on 09/14/2007 18:19:15
If you have factory amps and speakers in this vehicle already, that should be adequate mid/highs for now. However, it it's stock radio and speakers only, the subs will easily pound over them when you kick up the bass.
As for this Punch amp, the power draw specs are high. RF recommends a 140A fuse and #4 gage line. That is a surprise, but then again, this amp puts out close to 1200 watts @ 1 ohm too.
Driving your subs to full potential, may blank out the mid/highs and require a 4 channel amp later. I suggest planning for that eventuality and wire up your ride with 1/0 power cable and additional RCA's at the same time. Then, it will only be a matter of minor work later, as opposed to going over the job 2x.
I can help you plan it all out and be ready for the other upgrades as the budget permits.
Swez
PS Do you have a digital camera to take pics of the spaces you'll be working on later? This is very helpful to you and others that are trying to help/learn.
steve
Replies (10)
trunkisloud on 09/13/2007 23:44:25
here are the specs on this amp....
A/B (Patented Pure N-Channel) (Pat. No: US05631608, US05783970)
Power Supply Semi Unregulated MOSFET (Pat. No: US05598325)
THD + Noise (1 Watt) 0.1%
Signal-To-Noise Ratio (1 Watt) 75 dB
Overload Protection
Thermal Protection
Xtant Technology Cooling Continuously Variable Fan Speed
Connection Terminals StreetWires Connectors
14.4VDC Power
4 Ohms 100 Watts RMS x 2
2 Ohms 200 Watts RMS x 2
1 Ohm 300 Watts RMS x 2
4 Ohms Bridged 400 Watts RMS
2 Ohms Bridged 600 Watts RMS
INPUT (RCA Connection) Low Level
Hi Level w/ Smart Engage (Pat. No: US06556683)
INPUT SWITCH Input Sense 100mV-1V/1V-10V
Stereo - 100mV-10V
CROSSOVER Hi,12dB / Low, 24dB Mono @ 40Hz-350Hz, Defeat x
Quasi Parametric: Boost/Cut +/-12dB, Freq. 30Hz-80Hz
ARC: Cut 0-15dB, Freq. 200Hz
OTHER FEATURES Remote Subwoofer Level Control Parallelable x
DIMENSIONS Length 9-5/8" Width 20-11/16" Height 2-1/2"
this amp is a bad match for these subs....as you can only get 1 or 4 ohms with the subs...with these subs you can bridge it a 4ohms and get about 200wrms to each sub..and if you run a 1ohm load you would only be able to use 1 channel of the amp at 300wrms....these subs are rated at 400wrms each......you would be underpowering a bit...a 1ohm stable class d monoblock would do nicely here....heres a link to the wiring potential of these subs.....it will help you get a better understanding of the works in relation to the amp
http://www.rockfordfosgate.com/rftech/woofer_wizard.asp?submitted=true&woofer_qty=2&woofer_imp=4
MagorksAudio on 09/14/2007 00:33:14
wouldnt the subs get 300 watts rms each at 1 ohm because the amp specs say each channel puts out 300 watts rms? the amp is 2 channels one sub for each channel right? doesnt it mean when it says 300 watts rms x2 that each channel puts out 300 watts rms at 1 ohm? im confused. because the RF wirring diagram says that each sub is wired to 1 ohm right?
Str8Bumpin25951 on 09/14/2007 02:20:32
Question, I just re-wired my subs and went to go hook them up and there were sparks an i blew all my fuses what happened Where did i go wrong?
trunkisloud on 09/14/2007 06:55:00
the subs are wired TOGETHER for one ohm....there will be only a negative and positive wire running to the amp because the subs are wired together..how can you use 2 channels with only one set of wires? get it now? theres no other way to get 1ohm with these subs...
str8- sounds like you shorted your power somewhere..thats strange if all you did was hooked up the subs.
swez on 09/14/2007 09:38:38
Mag, this amp is not the best choice for those subs. (As Trunk pointed out well) It will work, but each sub will get about 200 watts RMS, no matter how the subs are configured to this amp.
The safest way to use this combo, would be to bridge the amp to Mono bridged mode and wire the subs for a net 4 ohm load. This amp will deliver a solid 400 watts RMS @ 4 ohms and each sub gets ~200 watts. That's not all bad, but the subs can handle more power as they are not all that efficient to begin with. (83dB SPL @ 2.83 volts) These subs are power hungry and to get the most from them, more power from the amp is your best bet.
Swez
PS St8, would you mind starting a fresh post and give complete details on the amp and subs, (Mfg & model #'s) used and how the subs were wired to the amp? It does sound like a major mistake was made when rewiring these subs. With luck the amp was not damaged in the process. Say more in a new post.
MagorksAudio on 09/14/2007 12:47:20
thanks i understand now i just keep ging backwards when think im going forward thanks fr all the help guys this site is the best. im short on money right now but when i get some ill donate to the site thanks again swez and trunk!!!!!!: }
MagorksAudio on 09/14/2007 15:36:19
I hooked up the RF P3s to the 7402 and bridge it so the subs are getting 200 watts rms to each sub it bumps but its not load anough for me. I think im going to upgrade the amp what kind of amp should i get I was thinking of some sort of RF amp. If I get a RF amp what size should i get? thanks agian for the help
swez on 09/14/2007 16:23:21
This may seem counterintuitive, but if you can get your hands on a matching MTX amp and carefully set the gains to match, using one amp per sub is a good recovery option here. (2 ohms/amp in bridged mode)
The biggest drawback here, these amps are high on current draw and some additional electrical support for these amps would be in order. At full power, these amps can pull about 100A's. However, since you'll be dialing back the gains for a solid 400 RMS per sub, current draw will be more like 80A's for the pair.
If you went with an RF amp, the Punch P1000-1bd is a solid choice. It is 1 ohm stable and can deliver up to 1,000 watts RMS @ 1 ohm loads. This amp has a bit more power than the P3's are rated for, but some careful gain setting will compensate for this. This amp is a bit on the spendy side too. The MSRP is $650.00. Off e-bay, the going price is about $350.00 + S/H.
http://cgi.ebay.com/Rockford-Fosgate-p1000-1bd-PUNCH-mono-amp-MSRP-650_W0QQitemZ320156766427QQihZ011QQcategoryZ64570QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
THINK through your options carefully as this plan has a few sharp treble hooks in it. (Power management specifically)
Swez
MagorksAudio on 09/14/2007 16:42:15
Thanks for the help i think im going to get the RF P1000-1bd because i rather have 1 amp for the subs less wiring and wouldnt draw less power then having 2 of the tose mtx amps? and would 4 gauge power wire be a good choice for the RF amp? I was wondering if i should upgrade the mids and the highs or are the delco stock speakers good anough? the bass does not drown out the sound so im sure if i sould keep them in or not. thanks again
swez on 09/14/2007 18:19:15
If you have factory amps and speakers in this vehicle already, that should be adequate mid/highs for now. However, it it's stock radio and speakers only, the subs will easily pound over them when you kick up the bass.
As for this Punch amp, the power draw specs are high. RF recommends a 140A fuse and #4 gage line. That is a surprise, but then again, this amp puts out close to 1200 watts @ 1 ohm too.
Driving your subs to full potential, may blank out the mid/highs and require a 4 channel amp later. I suggest planning for that eventuality and wire up your ride with 1/0 power cable and additional RCA's at the same time. Then, it will only be a matter of minor work later, as opposed to going over the job 2x.
I can help you plan it all out and be ready for the other upgrades as the budget permits.
Swez
PS Do you have a digital camera to take pics of the spaces you'll be working on later? This is very helpful to you and others that are trying to help/learn.
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