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Discussion Starter · #1 ·
I'm installing an updated stereo, Pioneer DEH-345 AM/FM/CD in my 77 El Camino to replace the original AM/8 track.
Front speaker connections went alright and everything works in front. But, the rear speakers in this thing are wired with only one one wire to the stereo, with the other side just grounded.
I recognize the right solution is probably to run new 2 connector wires all the way from the stereo to each rear speaker. But, in the meantime, will it damage the stereo to simply hook up one wire to each speker. If I do this, what do I do with the other wire to each speaker, just ground it?
I've done a search and see lots of discussion about speaker impedance. What impedance are typical for the original speakers in a 1977 model year? Will these damage a new stereo, probably designed for lower impedance speakers?
Thanks for any insight.
 

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Id install new speaker wire with 2 conductors each. I think the posibility of getting ignition interference is higher using the one wire.

It also might damage the radio. I know most aftermarket radios say NOT to use the original one-wire setup in the instructions.

The original speaker impedance should not be a problem (probably 8ohms). Most amplifiers will work over a range of impedances, it will just put out more (or less) power at the different impedance (like 50watts @ 4ohms and 30watts @ 8ohms).

You will probably be dissapointed in the sound with the stock speakers, though. Stock speakers are really crappy, and are usually the first thing to go bad.

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Charles Perrell
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65 malibu SS Convertible
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Charles' post basically answered all the questions, but I'll add to it:

In 1977, Delco's love affair with "10 ohm speakers" was still alive and well. You'll most likely have the 10 ohm units still in place.

Do not, I repeat DO NOT try to run any modern stereo with factory "3-wire" rear speaker systems or other non-floatingground system. Previous to 1978, Delco units were still using non-floating grounds for speaker returns. This means each speaker
(-) "sees" ground at some point, either an internal point inside the radio, or at it's mounting location. Chassis ground/B-/speaker - was all the same. Today that is NOT the case!! Connecting any of your modern floating ground output stereo speaker leads (or accidentally) to a ground will result in damage. Poor Mr. Audio Output IC will die a horrible death.

Running 10 ohm speakers with your modern radio (after of course updating the wiring), will work, BUT, 1)the power dissipation will be less, modern units are meant to run on 4 ohms for maximum power output. 2)You'll likely blow-up the old speakers when any kind of reasonable "cruising volume"
is selected. 3)Even if the speakers work, speakers that old are due for upgrades, not much life in them as the paper cones have aged and the voice coils are probably rubbing. Replace all of your speakers with modern ones!
 

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Discussion Starter · #4 ·
Thanks for the replies. I guess I knew these were the right answers, but wanted to hear other opinion. I will re-wire the speakers and replace them as soon as I get time.
Thanks.
 
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