66 am radio

[Newt]

Will a 66 am radio have enough amps to run 6x9 speakers or will they only run the dash speaker? Thanks for any help.

[Newt]

Will a 66 am radio have enough amps to run 6x9 speakers or will they only run the dash speaker? Thanks for any help.

[TheTempest]

The stock radio should have enough power to run either *one* 6x9 speaker *or* the dash factory unit. Pontiac A-bodies only have one factory cutout for a rear 6x9 speaker; hopefully you are not considering *cutting* additional holes in the rear shelf.

It is not just amperage you need to consider but the impedance rating of the
speaker(s)you are using. The stock dash unit has a rating of 10 ohms and most modern aftermarket spkrs have ratings of 8 ohms (with a few rated at 4 ohms). Use of a single 8 ohm spkr should not cause any problems. What happens when the total impedance rating of the spkr(s) you're using is too low is that the power amp in the radio will flow too much current and overheat the output transistors; this will damage the amplifier. All of the factory multi-speaker options (sepra-phonic & verbra-phonic) allowed for the use of a single rear speaker. Even the stereo 8-track option used the dash spkr and single rear deck spkr for the left and right channels (not the epitome of stereo high fidelity). I could be wrong, but I don't believe any of the factory multi-spkr set-ups allowed for the simultaneous use of front and rear speakers unless they had a dedicated amplifier (such as the reverb amp for the verbra-phonic and the appropriate channel amp for the 8-track).

If you *really* must cut the rear deck for your pair of spkrs, then make sure they have a 4-8 ohm impedance and connect them in series:

R
A (+)-------|6x9 spkr|--------|6x9 spkr|----|gnd
D |4-8 ohm | |4-8ohm |
I
O (-)---------------------------------------|gnd

This setup will "show" the output stage of the radio's amplifier a total impedance of 8-16 ohms. This setup shouldn't cause any undue harm to the radio power amplifier.

Sorry for all the "rocket science" but if you're not careful, you can toast the old amp in your original radio quite easily.

Hope this helps

Mike
'67 Tempest Custom Sport (post) coupe

[Newt]

Thanks for the info. When I bought the car it had a cassette player in it and two holes were already cut into the shelf. I want to make the car as original as possible, so I will be replacing the rear shelf, and dealing with the dash speaker.

[TheTempest]

The restoration part sounds great! Here's some of my ideas for getting vintage sound in my car. Part of my restoration will be to install a sound system using options of the period. After seeing what original '67 AM/FM stereo radios sell for (there was currently one on eBAy that was high bid at $501...and the reserve had not yet been met!), I needed to rethink my strategy. Using my existing AM radio, I have purchased a Delco reverb amp and dash switch ("verbra-phonic" sound, sucha cool name). In addition, to get the "tunes", I purchased an FM converter (an FM tuner that converts the signal to AM, is installed inline with the antenna lead and can be hidden in the glove box). I will have the original dash speaker "rebuilt" (reconed and new dust shield) and use an aftermarket 6x9 rear shelf speaker. With this setup I hope to be able to recreate, somewhat, the "Top 40" AM sound that I grew up with (FM stations played "elevator music" back then). If I do want to get modern and play some favorite CD's, there are adapters that convert the output signal of your portable CD player to an FM signal (which would be picked up by the FM converter and played thru the AM/reverb setup). In any event, everything will wash down into that beautiful, static prone, limited frequency response and dynamic range "AM sound". All the items I've gotten have been thru eBAy and internet searches. Good luck with your restoration!

Mike

[Kurt Zimmerman]

Mike,

Haven't heard from you in quite some time. Did you get buried it the Georgia snow a few weeks ago? I think it was only the first or second time we sold out of sleds at the Georgia store!

Kurt