bad wiring kills amp- fixed & what to do now?

[C.Palmer]

This is a follow-up post from when I blew my 450S power series rockford amp. I need to wire my JL 12-W6 at no less than 2ohms so I don't repeat my same mistake. Can someone help me out here? I'm getting a bunch of mixed feed back on my speaker ratings and it's driving me crazy. Now I see this off the rockford page that further confuses me (see differences between both images) the wiring is the same so is the different load due to different speakers? I'm finally starting to understand ohms and all that good stuff so bare with me... thanks! :D

wiring diagram #1
wiring diagram #2

[C.Palmer]

I think I might have just answered my own question. the 3ohm wiring diagram in the link is how i had it before and someone was telling me i was running below 2 which caused my amp to go. I'm going to keep my original wiring since rockford says my gains were too high which caused the over-heating (not mentioned by my friends or anyone on this board).

Anyone see any problems with keeping this wiring plan?

W6 specs/wiring diagrams

[v6maro]

I have a JL audio 300/4 amp for sale in the "for sale" section, check it out for a great quality amp.
-Steve

[Backfire]

Did Rockford tell you it was ok to run the amp at 1.5ohms per channel? Did you tell them that you were running it at 3ohms or 1.5ohms? If you accurately described your setup to them and they said it will work, well...they know their amps better than anyone else. Don't know why you would need anymore info.

As far as the first two diagrams go, they are showing two different speakers. The first one has two 4ohm coils, the second has two 2ohm coils. Yours has two 6ohm coils, but sounds like you already have a good handle on that stuff.

[C.Palmer]

<blockquote>quote:</font><hr>Originally posted by Backfire:
Did Rockford tell you it was ok to run the amp at 1.5ohms per channel? Did you tell them that you were running it at 3ohms or 1.5ohms? If you accurately described your setup to them and they said it will work, well...they know their amps better than anyone else. Don't know why you would need anymore info.

As far as the first two diagrams go, they are showing two different speakers. The first one has two 4ohm coils, the second has two 2ohm coils. Yours has two 6ohm coils, but sounds like you already have a good handle on that stuff.<hr></blockquote>

It's all becoming a little clearer now, basically what I need to know is if I wire my sub as shown by the JL wiring diagram on my 6ohm coils, is my amp going to see my sub at below 2ohms (bad) or at 3 which I think I'm at (good)??

[Backfire]

The diagram in the top left of the JL page, shows a parallel arrangement for the coils and means the speaker will look like 3ohms at the end of the speaker wire. The problem you have is if you are bridging you amp. I believe the 450s is a two channel amp. If it is a two channel amp, and you are bridging the sub across the two channels, then each channel will act like there is a 1.5ohm speaker on each channel.

If Rockford told you that you could run below 2ohms per channel, then it may work. But if they said that the 3ohm speaker is ok because each channel could handle a 2ohm load, they may not have understood your setup. You would be attempting to run the amp below Rockford's specifications.

The simplest way to put it is this. Rockford says in the manual for you amp that "These amplifiers are not recommended for impedance loads below 2ohm stereo or 4ohm bridged(mono)." What you are attempting to do is use an impedance load of 3ohm bridged, which is obviously below the 4ohm bridged specification.

Now, if you want to be safe, you could wire the speaker coils in series, which I believe was the top right image on that JL page. That would be a 12ohm bridged impedance, which is well above the 4ohm bridged minimum. With that configuration, using the manual specifications for power at 2ohm and 4ohm setups to estimate, I would guess that your sub would get around 150W from the amp.

[ August 14, 2002: Message edited by: Backfire ]</p>

[superbird]

To the best of my knowledge BACKFIRE is correct. I used to have jl w6's . They are a great sub and will seriously pound but your problem is that with only one sub it is almost impossible to wire it and still pull any power from your amp unless the amp is one or two ohms stable. My advice is either get another amp or get another sub. I had two 10W6's running off of a phoenix gold xs2500 which was two ohms stable and had no problems.

This last part I am gonna tell you is strictly my opinion with my experience with Rockford amps. Their amps run hotter than just about any other amp and are constantly going in to protection mode and cutting off when they get too hot.

Someone on sound domain once said "Yeah a rockford amp is great. It's the only amp that you can heat your car with in the winter and cook breakfast on it the summer"

So i would ditch the amp

Just my 2 cents though

[Backfire]

<blockquote>quote:</font><hr>Originally posted by superbird:
They are a great sub and will seriously pound but your problem is that with only one sub it is almost impossible to wire it and still pull any power from your amp unless the amp is one or two ohms stable.<hr></blockquote>

I have that same problem with an old Soundstream SPL12. It has plenty of output for me, but because of the dual 4ohm coils, I don't extract the full power from my Fosgate amp. I would really work the amp if I tried to run a 2ohm bridged load. The 8ohm works fine for me with the current amp, but with a smaller amp it can be difficult to get the needed power. And I have had the same experience with Fosgate amps as Superbird. I haven't deal with a lot of them, but of the 4 that I have installed, all different models, each runs hot, even when in a 4ohm stereo setup. Some Fosgate supporters say that is good because the heatsink is pulling more heat away from the circuit board, but that isn't how heat transfer works. The heatsink cannot be any hotter than the guts of the amp, or the heat would flow back into the amp :D

I built a setup using a single 15W6 and a Fosgate 800a2 in a friends Z28. With an amp that size, it still pounds when run in the 12ohm configuration. But if the amp was much smaller, there would be some issues. I would try the series wiring for the 12ohm bridged configuration. See how it sounds. As long as you aren't going for SPL numbers, that should provide you with good sound and a little bump to go with it. ;)

[ August 15, 2002: Message edited by: Backfire ]</p>

[C.Palmer]

:mad: damn! What pisses me off is that I have a good sub and a good amp (as long as I can keep it cool) but they just aren't good together with my current configuration. I'd prefer an older RF amp over this 2002 model but hey what can I do about it now w/ no green?! I Think I'm just going to run the sub off one channel until I either A) get another sub or B) get a different amp. I got 3 notices in the mail that I was accepted for further testing on some jobs I applied for so my days w/o money are coming to an end soon... I CAN FEEL IT THIS TIME!! :D

Oh and superbird... my last amp was a PG XS2500 and I loved that amp! I wish I never would have sold it. The only reason I went with Rockford over PG this time is because I had some killer connections in Oregon before I moved