Rockford Fosgate 750s Needs To Marry Old JL Audio 10W6's in Mono ??????

Fada Starky

CarAudio.com Newbie
Feb 25, 2022
4
0
I have a Rockford Fostgae Amp which I have had for over 15 yrs...(still works). I "ve just had a pair of JL audio10W6's Dual Voice Coils also over 15yrs refurbed and ready to go.

Whats the best way to wire this set up and how.

I've been told to wire them to the amp in Mono , but how ????

I'd really appreciate any help from anyone who can guide or assist me to get these guys married so that they can play sweet music together for the rest of their lives.

Rocky Fosgate 750s Amp
4 Ohm Load Per Channel 187.5 Watts
2 Ohm Load Per Channel 375 Watts
4 Ohm Bridged (Mono) 750 watts

See Attachment for JL's

Cheers
 

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Deiimos

CarAudio.com Regular
Apr 27, 2021
140
56
If they are indeed dual 6 coils, then 6-ohm is going to be your only option if ran bridged, so wire them like JL diagram shows for 6-ohm. Don’t run that amp at 1.5 ohm, it will kill it, it's a great amp, but that's too low.

How to connect the subs bridged / mono from the manual (positive speaker wire to the left channel postive output, and negative speaker wire to negative right channel output). Note that you need to set both "gains" the same, a DMM and test tones would be best since the amp has seperate gain adjustments for left/right.
750s bridged.jpg
 

Fada Starky

CarAudio.com Newbie
Feb 25, 2022
4
0
  • Thread Starter Thread Starter
  • #3
If they are indeed dual 6 coils, then 6-ohm is going to be your only option if ran bridged, so wire them like JL diagram shows for 6-ohm. Don’t run that amp at 1.5 ohm, it will kill it, it's a great amp, but that's too low.

How to connect the subs bridged / mono from the manual (positive speaker wire to the left channel postive output, and negative speaker wire to negative right channel output). Note that you need to set both "gains" the same, a DMM and test tones would be best since the amp has seperate gain adjustments for left/right.
View attachment 36041
Hi

Thanks for the reply.

I have gone with the JL recomenndations of running it at 6 ohms, but when the gains for each channell are adjusted it affects the sub on the other channel , i.e turn up left gain and sub on right channel goes down.

Any clues why this is ??

Thnks in advance
 

Fada Starky

CarAudio.com Newbie
Feb 25, 2022
4
0
  • Thread Starter Thread Starter
  • #4
Hi

Thanks for the reply.

I have gone with the JL recomenndations of running it at 6 ohms, but when the gains for each channell are adjusted it affects the sub on the other channel , i.e turn up left gain and sub on right channel goes down.

Any clues why this is ??

Thnks in advance
Also please see screen shot of Amp Manual , it suggest I can bring the amp to a 2ohm load giving 375 watts pc. Would this be possible with the JL 10w6's ???

Please advise

Cheers
 

Attachments

Deiimos

CarAudio.com Regular
Apr 27, 2021
140
56
Something sounds wrong.

A pair of subwoofers wired to 6-ohm in bridge mode will both move the same, so the left or right gain adjustments, even if adjusted individually, will effect both subs at the same time. If one sub is moving more than the other while individually effected by gain adjustments, something isn’t right in the wiring somewhere. Clear photos of all the wiring may help.

As for wiring one sub per channel. Those subs are DVC 6-ohm, so you can't get 2-ohm per channel, so you are stuck with 3-ohm per channel if you do that, same exact power as you will get running it 6-ohm bridged and won’t give you any more power. I only recommend running each sub off its own channel if your box has separate chambers. You might get bad performance if you don’t get the gains set right and the subs are not moving equally in a single chamber box.
 

Fada Starky

CarAudio.com Newbie
Feb 25, 2022
4
0
  • Thread Starter Thread Starter
  • #6
Something sounds wrong.

A pair of subwoofers wired to 6-ohm in bridge mode will both move the same, so the left or right gain adjustments, even if adjusted individually, will effect both subs at the same time. If one sub is moving more than the other while individually effected by gain adjustments, something isn’t right in the wiring somewhere. Clear photos of all the wiring may help.

As for wiring one sub per channel. Those subs are DVC 6-ohm, so you can't get 2-ohm per channel, so you are stuck with 3-ohm per channel if you do that, same exact power as you will get running it 6-ohm bridged and won’t give you any more power. I only recommend running each sub off its own channel if your box has separate chambers. You might get bad performance if you don’t get the gains set right and the subs are not moving equally in a single chamber box.
Hi

The box I have is a double 10 box with 1 port for each chamber. When I wired the subs in 2 channel mode and adjusted the gains I could not get them to move in sync. Is the amp faulty ????
 

Deiimos

CarAudio.com Regular
Apr 27, 2021
140
56
It is an older amplifier, so the switches and potentiometers may be dirty internally and need cleaned. Not a simple task if you don’t have the experience. However, I don't think that is the problem here.

Could try cycling the switches several times, and rotate the pots all the way through there cycle several times.

To perhaps rule that out, you could turn the head unit volume all the way down, gains on the amp all the way up, turn the head unit volume up enough to hear sound and test one speaker at a time on the left channel and then right channel to see if they have the same volume.

Something still sounds wrong with the wiring, because, at 6-ohm bridged mode both subs should be moving in sync despite one of the gain pots being all the way down (bad for the amp to not have the gains matched when bridged, but the subs will be in sync), being that wasn’t the case and you said adjusting one gain effected the opposite sub, I still lean towards wiring.

Otherwise, hopefully someone else chimes in with thoughts.
 
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