Jensen smoked

[Turbo Dog]

I have a Jensen Am-FM CD , model CD-615X. i bought it becasue it is a 1.5 din size. Anyway, I hooked up two amps to it, a Boss REV 650 and a Rockford Fosgate 450S. It worked fine with the Boss for over a year, but I think the RF amp was too much for it somehow. First I noticed the rear channels cut out, then I saw smoke coming from the Jensen! I wasn't even playing it loud. The RF amp is powering an Image Dynamics 12 inch subwoofer. After letting it sit, I tried the Jensen and it played fine, but I'm afraid to use it now. Any suggestions to avoid this problem in the future? One more thing. The pre amp output RCA wires from the Jensen added too much static from day one, so I was using the rear speaker wires connected to a high/low impedance adaptor with RCA outputs. Thanks for your help.

 

[TURBOV6]

Wow you saw smoke and still working fine? You probally hade overheated the amp or speaker wire shorting to ground. I would make sure you got the correct ampre on the fuse for future problems. Most amplifiers have protections that prevents those problems, but sometime the "cheaper" amps do work that well. But if smoke came out it will not last too long and you should keep a good eye on it and a fire extingisher close buy just in case

 

[Turbo Dog]

I noticed that Rockford Fosgate sells a head unit with three sets of RCA pre amp outs. One for the front, one for the rear, and one for the subwoofer. Could my problem have been caused from splitting the rear speaker wires to run two amps? I want to make sure this doesn't happen again. Does anybody have an opinion on rockford fosgate head units, specifically the RFX 9200? How do most people hook up multiple amps? I need one for my rear speakers and one for my subwoofer. Thanks!

 

[Audiowizard]

Originally posted by Turbo Dog
Does anybody have an opinion on rockford fosgate head units, specifically the RFX 9200?

When they first came out, they were made by Delco electronics but I am not sure if they are still made by them or not.

 

[TURBOV6]

Originally posted by Turbo Dog
Could my problem have been caused from splitting the rear speaker wires to run two amps?

No.

The new Rockford decks are made from another company, fogot who. Its not a bad piece, looks sharp and performs well. But I would stick with another manufacter.

 

[Turbo Dog]

I posted the same question about the Jensen smoking on the Q&A board at www.partsexpress.com . They told me that if my ground was not secure in the trunk, then the Boss amp would go looking for a ground at the head unit, thus frying the output transistors. They said the Rockford has some other kind of internal wiring which would not cause it to look at the head unit for a better ground. I guess this makes sense, as I put a ring terminal on the ground wire and may not have secured it well enough to the ground hole in the trunk.

 

[GNandTTA]

They told me that if my ground was not secure in the trunk, then the Boss amp would go looking for a ground at the head unit, thus frying the output transistors.

That makes sense.

But I doubt the Rockford has any 'special' circuitry to prevent that. EVERY headunit I've ever seen has the RCA shields directly connected to ground. It has to be that way so the entire system has one, and hopefully only one, reference to ground. Without a reference to ground you would get alot of interference because the shield would be floating or worse act as an antenna introducing all kinds of strange noises into your system. That is why when adding an amp it is crucial to have the ground connection absoultely mint.

 

[Turbo Dog]

GNandTTA,

Here is what they said: Check your grounding situation in the trunk. Make sure the location is close to the amplifiers as possible and that the paint is scraped down to bare metal. Use a gold plated (to prevent corrosion) crimp ring terminal on the ground wire and secure the entire assembly with a self tapping screw and a star washer to prevent movement.

I'll bet you're saying "BUT THE JENSEN IS SMOKING! NOT THE TRUNK!" Yes, well, if the chassis ground is loose or inadequate, the Boss amplifier will "seek ground" though the RCA cables and literally burn the circuit traces in the radio. That explains why the radio smoked but still works.

The Rockford amp won't do this because it has the TOPAZ input that is completely isolated from ground. The Boss amplifier isn't so lucky...

HTH

 

[GNandTTA]

I thought you were talking about a Rockford head unit. Yes the Rockford amp has a differential input which prevents back feeding current.