plonka

Today I installed a factory delco 8 track player in my 76 cutlass (I used to have the standard delco radio). I tested it , everything worked (two dash speakers, one rear 6X9, they only came with one 6X9). Whenever I turn the ignition off then back on, only one dash speaker works out of all three. If I remove the one blue wire(the rear 6X9 speaker) then reconnect it, all three speakers work again until I again turn the ignition off, then it's the same thing. Any ideas? Thanks.

oldcutlass

How do you have the speakers wired, power and ground wired?

plonka

The radio is hooked up exactly the same using all factory harnesses as the old radio. The only thing I didn't connnect was the mounting support screw on the right side of the radio because the new radio didn't have the threaded insert for the screw.

White_Knuckles

Okay that's some pretty strange stuff. The missing screw mount is no problem as long as the unit isn't loose and wiggling.

Start troubleshooting by seeing what is not affected. Unhook the rear speaker and see if the front two are normal cycling the key. Now connect the 6X9 and remove LF and retest. Continue isolating RF, LF & RF, etc. until you find any combinations working properly. Now you solve for when the rogue speaker(s) are added where the problem may live.

Hopefully you sent only one channel to the rear? Should you have tied rear L&R together you may have introduced a shut down issue. The amp speaker outputs must be sent to individual speakers never tied in parallel.

plonka

My old radio was wired with only one blue wire to the rear and then was grounded from the 6X9 to the frame. The new radio looks like it was set up for two rear speakers bacause the harness on the radio has +&- L&R (four wires)I simply connected the blue 6X9 wire to any of the four rear connections. It doesn't help that I'm not an electronics guy. I'll follow your above steps. I appreciate the help.

oldsonharmont

I believe the factory Delco AM/FM 8 Track units from this era needed some sort of external unit to work properly. (which looks like an external voltage regulator with a plug) You can tell by checking the rear of the radio for an extra harness plug. Your car may only be wired for the radio it came with and you might be in business if you can locate the missing external unit. Sorry but the name of that part escapes me right now.

oldcutlass

If the new radio is setup for 2 rear speakers, how do your have it wired to compensate with only 1. Each amp output has to have a correct load on it.

plonka

I'll post some pictures later today. I think that might clear things up a little. I can't think of a better way to explain it right now.

oldcutlass

Also what most peolple don't realize is that if your bench testing an old radio, you must also have an antenna load, without it you will burn up the radio.

MDchanic

Sorry, but I have to disagree.

This is true of 2-way radios, like CBs - if you operate the transmitter without an antenna or a dummy load, you can burn out the output transistors - but not of receivers.

- Eric

plonka

I'm not bech testing it. It is installed. When I speak of pulling the blue wire, I'm reaching under the dash. I have the main antenna hooked up. There is a red (labeled PED) wire that I believe is for the remote entenna(if equiped) which I don't have. I have the windshield antenna. P.S. Still working on getting the pics here in a little bit.

W70442

I think the box you are thinking of is the multiplex unit that was used on "stereo" radios back in the late 60's and early 70's. I'm pretty sure that a 76 player would not need a multiplex box.
By the way, the multiplex box contained the components that made it "stereo". Those components were all incorporated into one box by 71.

plonka

Here are the pics. You can see from the old uninstalled radio, it had a three spaced terminal with one blue wire for the 6X9. In the picture of the installed 8 track, there is a four space terminal and as you can see I have the blue rear speaker attached to it. Whenever all speakers are working and I turn the ignition off, I have to remove this blue wire then reconnect it for all three speakers to work again. I've been told that I need to install a 10 ohm resistor to trick the radio into thinking there is a second rear speaker, therefore making everything complete. Does this sound right?

White_Knuckles

The resistor would be needed to simulate a speaker load. The resistor must be rated 10+ watt at 8-10 ohms. This would be a large ceramic resistor that at loud volume would get warm. But why is this needed? Not to "trick" the radio but to prevent killing one of the rear channels.

So starting with the fronts, with the rear 6X9 unhooked, pan the L-R "balance" from one side to the other. Did the sound move back and forth? You may not even have the stereo L/R channels hooked up properly? I think the old radio may have been mono as in 1 channel with maybe a front-rear "fader"?

If it's mono the front two speakers may be tied together? What you need is dedicated speaker wiring runs to LF and RF. These should operate in stereo from the new 8-track's front speaker outputs. Now the rear two need attention. One of them, let's say Right, will go to the rear 6X9. The Left channel will be strapped with the resistor across the speaker terminals to prevent blowing the amp outputs. You will not have a rear left audio channel. If that baby has a front-rear fader, it will work.

I'm thinking you got in a mystery with the factory connector. That era was pretty crude transistor technology with little to no "logic protection". That unit detecting a missing speaker needing the other removed to restore audio is crazy stuff. Trying the load resistor isn't a bad idea as it needs it anyway. Maybe the guy knows something I clearly don't? I think this will require more testing on the factory harness/pins. How does it operate when the blue rear wire is left off?

Edit: Are you avoiding cutting the rear shelf? You could drop in a couple decent speakers and have true stereo front and rear?

MDchanic

I think White Knuckles has summarized it all nicely.

You need a correct diagram of the hookup of the old unit and a correct diagram of the hookup of the new unit, or you are just screwing things up and will destroy the new unit.

The older GM radios are very sensitive to load, and their output transistors WILL blow if the output load is wrong.

What's wrong with connecting a fourth speaker, anyway?

- Eric

plonka

I just checked the window sticker option list. It lists the radio as AM-FM Monaural, and yes it only has front and rear fader, no left and right. So if I just added a second rear 6X9 I wouldn't have to worry about the resistor method? BTW, with the rear speaker disconnected I can turn the ignition on and off and never lose sound from the dash speakers, it was only when I hooked that rear speaker up that it screwed things up. The new 8 track player is obviously stereo, and I thought I could just hook up the one rear speaker wire just like the old mono radio and things would work fine.

MDchanic

Look, you are way out of your comfort zone here.

You CANNOT connect a 1970s four-channel stereo to a split one-channel Mono speaker system and make it work.
Sorry.

You WILL permanently damage your stereo, and may have done so already.

A STEREO system has TWO channels, and the particular stereo you are trying to use has FOUR. The speakers in the car are set up for ONE with a splitter.

There is NO WAY to connect your stereo unit to your speakers without burning out at least one output transistor, and even if you could, why on earth would you want to listen to only one channel? And how would you decide Left or Right?

If you want to have a STEREO, you NEED to have either two or four speakers, depending on the radio unit.
In your case, it HAS to be four.

So, what you need to do is to:

1. Look up the wiring schematic for the car
2. Look up the wiring schematic for the stereo
3. See which wires in the car you can use with the new stereo, OR decide that you will just run new ones (which is probably simpler in the long run)
4. See how many wires you will need to run for the new stereo (some of them had two wires to each rear speaker, some had one each, and returned through ground)
5. Decide where you will place your new speakers
6. Remove relavent parts of interior
7. Cut, drill, or whatever you have to do in order to install the correct speakers
8. Install the speakers of your choice (they MUST be 8-10Ω for a '70s Factory GM stereo)
9. Run wires and connect
10. Enjoy listening to your 8-Tracks, if you haven't burned up your output transistors yet.

- Eric

plonka

Thankyou for everyone's help. I talked to Greg at Electro Tech,Inc. I ordered a second rear 6X9 and will re-wire accordingly. I haven't destroyed any outputs on the 8-track yet, and regardless, I paid $38.00 for it on Ebay. A bargain for a fully working unit. Cheers!

MDchanic

Excellent.

Be sure you have the front speakers wired separately, and not together.

As for blowing output channels, I know it can be done because when I was a kid in the seventies and eighties, I did it to more than one Cadillac radio (which cost about $20 each then, which was a lot of dough) for my Chevelle.

I'm glad you were able to talk to someone who could give you good clear advice.

Good luck!

- Eric

White_Knuckles

The Connoisseur is on this - BAM!

Now that this is solved, I'm tri-amping a digital audio processed series of dedicated, component speakers from a headunit with dual RCA (line) sends. The low freq. "sub" inputs are in stereo where tapped line inputs will be routed to a 2-channel sub amp. The single 12" driver, mounted in a tuned enclosure, has dual voice coils. The cross-over points to the tweeters, mids and low-mids are controlled by ambient modeling from the DSS processor. When remote switching the sub to power on, my cigarette lighter vaporizes. I think the fuse is good ...

Okay, all above was a joke but based on current systems I've helped my son's friends with. It's fun thinking back how simple audio was in the 70's. It would be cool to see if that ol' beast has decent sound. I'd have the shop install branded co-axial speakers front and rear. The radios had good FM capture so who knows, it may sound good?

MDchanic

My '73, which is a fun car, not a fancy car (I don't believe that any car later than '72 is an antique), has high-quality tweeters behind the dash grilles, and 6" mids carved into the doors just behind the front seats (the ONLY place in those huge doors where you can plant a speaker), a mid-high amp under the driver's seat, a sub amp under the passenger seat, all connected via custom-soldered RCAs (by me, natch), and a 10" sub in the trunk.

All components were flea market finds, nothing more than $20, and it sounds great.

One thing that I've learned in over thirty years of installing car stereos in my cars is that the OEM stuff from the '60s through the '90s is crap, and if I want to be able to enjoy the stereo, it's all got to go, every time.

- Eric

oldcutlass

There is another option for the single rear speaker. They make a dual cone single mount speaker that allows you to connect stereo to one speaker.

Not suggesting this particular one, just something like it.

http://www.retrosoundusa.com/products/details/id/67

plonka

The company I ordered my second 6X9 from also had the dual cone stereo option. My original goal was not to have a "Rockin" stereo in my car, but to keep it as close to stock and original as possible, just working. I want that true analog tape sound that I remember when I was younger. I only wanted one rear 6X9 because that's how it came from the factory. Most of the time I don't even listen to music, just the engine and that sweet exhaust note.

oldcutlass

Yeah, IN A GADDA DA VIDA, just does not sound the same to me without a track change in the middle of the song.

plonka

That was probably a buzzkill for Iron Butterfly fans at the time.

White_Knuckles

Hmmm, I still smell the strawberry incense burning to allow a Zen-like ambiance when appreciating one's Butterfly drum solo.

But I don't miss cramming matchbooks into my player to jack the tape into head alignment!!

oldcutlass

Ahhhh yes, the trusty matchbook, it was a revolutionary automotive tool. There was a smokey scent emitted from the interior of the car, however is was not strawberry incense, no further details needed.

plonka

2nd rear 6X9 installed, all four speakers working like they should with no issues. All that fuss for such a simple fix

oldcutlass

Glad to hear it's working - good job.

MDchanic

Ah HA!

Excellent!

Glad you got 'er going. Enjoy the tunes!

- Eric

White_Knuckles

So, how does she sound? FM radio would be the benchmark for testing. Your 8-Track cart got a call from the 70's...

They want it back!

plonka

Well, it sounds better than three speakers. I tested it with the radio, not the 8 Track. Works for me. I also painted and installed a pair of sport mirrors instead of the single chrome rectangular mirror. Stoked!