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Orig. Radio/8-track Combo

37K views 17 replies 7 participants last post by  Brucecc1967 
#1 ·
I hope this is the right catagory..I know this is a subject few want to participate in, but I can't figure this out and it's driving me NUTZZZ!

Ok, picture this..67 Camaro from the factory has an underdash 8-track player, 4 speaker, etc..now, when it gets to the dealer, the owner wants an AM/FM radio installed since they were not available from the factory..Now, I know this: You could get JUST an AM/FM mono even with the stereo 8-track there, OR get an AM/FM stereo..If the guy wanted the AM/FM stereo too, a multiplex unit was installed right OVER the hanging 8-track, correct? (assume this car has no console). OK, I figured out that to do this there needs to be a fader knob installed on the RH radio knob. The same one used if a car had just a rear seat speaker..This fader is to control eith 8-track or radio usage (otherwise both systems could technically work simutaniously) The thing I can't figure out is how the two speaker harnesses were connected????? I searched and found no other pigtail part #'s anywhere, so, how did they do it??? ten million dollar question!
THANKS!!!
 
#2 ·
You may want this moved to the 'electrical' section. I believe that 'Mark C' is a pretty good source (expert) on the audio systems for first gens. Sorry, I can't help.

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Dave
'69 Z11 Pace Car, 350/4 speed, manual top, console w/gauges, tilt rosewood wheel, AM radio
 
#3 ·
If you don't have A/C in a 67, you got an 8 track that looks like the 68/69 console mounted unit, except it was mounted under the center of the dash facing rearward. A/C car required a console, as there isn't room under the dash with the A/c duct work. The unit still sat on the front of the console facing back. 8 track was only available with AM or AM/FM mono radio in 67. The multiplex AM/FM unit used in 67 Camaros was a generic unit (4 knob unit under the passenger side of the dash) only installed by the dealer.

Normally the output of the radio only feeds the dash speaker and is totally separate from the 8 track outputs. If you ordered the U80 option (auxiliary speaker) you got a potentiometer that sits under the radio tuning knob that split the mono output into two signals. One goes to the dash, the other goes to the rear speaker that was part of the U80 option. If you got U80 with an 8 track, you already have the right rear speaker, so the output going to the rear speaker goes thru a switch in the 8 track unit and gets connected to the 8 track output to the right rear speaker. The speaker connection between the U80 fader is the green wire in the 8 track power harness. This is the 3 wire red, Green Black harness that plugs into the radio power connector in the dash harness. The 8 track tape switch is closed whenever a tape is not inserted into the player and this connects the radio rear speaker output to the right rear speaker output from the 8 track. The same switch cuts power off to the radio when a tape is being played so you won't smoke the output amplifiers in the radio when the 8 track is playing since You can not operate the 8 track unit in parallel to any kind of radio.

In 68 and 69 there are two different models of 8 track players. One is used with mono radios and the other is used with a multiplexed radio The ones used with multiplex radios that have an additional set of input wires from the output of the multiplex unit. These units have a 3 wire harness, and two 6 wire harnesses, an 8 wire harness to the heat sink up under the dash, and a black ground lead. Mono radio 8 tracks only have the 3 wire, a 6 wire speaker harness, the 8 wire heat sink connector, and the ground lead. The multiplex 8 track unit is installed in the wiring harness between the output connector on the multiplex unit and the speaker harness connector. The multiplex input is connected to the same switch that the mono radio uses, except it uses 4 sets of contacts instead of the 1 set the monos use. The radio sends it's multiplexed output to the 8 track input connector harness and as long as there is no tape in the player, the signal goes right out on the 8 track output harness to the speakers.

Since there is no 67 multiplexed 8 track unit you can not install an 8 track with a multiplex radio setup, unless you get a 68 or 69 multiplex 8 track unit. These are about as rare as they come. You could try to make up your own input harness and connect it to the tape switch, as all the necessary terminals are they inside the 8 track units, just no wires. You will end up with knobs all over the place as well, the 4 for the 67 dealer installed multiplex radio unit, and the 4 on the 8 track. The settings on one will have no effect on the other as the 8 track unit is nothing more than a junction, and switching point for connecting the wires from a common set of speakers to two separate stereo systems.

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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine
 
#4 ·
Hey Mark, thank you very much for taking the time to explain these things. The 68 and 69 8 track/multiplex systems I understand well but there are a few things I must differ with you on..first, 69 never used the 4-knob multiplex unit, correct? I believe all the controld were imcorporated into the radio making it a "blue light" unit and a seperate amplifier was mounted above the glove box, correct..ok, 69 is easy. 68's you've cleared up for me beiing there is a seperate set of wires designed to be used with the multiplex...but, the 67's are an odd ball..I have one of those original 67 Camaro assesory bookets...you know the one advertises floor mats, child proof door locks and the one I like "tri-volume horn for a strong, pleasant warning" HA HA! Is there such a thing as a pleasant warning? Anyway, in there it states "The AM/FM radio and Stereo Multiplex can be installed with a tape player" so there can be an amazing 8 knobs under the dash..I just can't figure out how the speaker harnesses are bound together. And, there is no seperate part #'s for multiplexes with 8-track and without..just one: 986932. If you look at an assy. manual you can see how the 8-track mounts using the underdash bracket..there are two sets of mounting positions and a plate that screw on over the player when multiplexes arent used. What do you think? Thanks again
 
#5 ·
The 69 and late 68 AM/FM multiplex units did away with the separate 4 knob multiplex units and moved the Bass, Treble, Balance and Fade knobs into the radio, and hid the multiplex unit behind the dash. Early 68's had a console mounted multiplex head unit with those 4 knobs in it.

There should be only one multiplex unit listed for 67, but if you could get an 8 track with the multiplex then there should be two 8 track units. One for use with mono radios and one for the stereo setup.

The connection of an 8 track to a multiplex unit is pretty straight forward. You unplug the 6 pin multiplex output harness from the speaker harness. You plug the multiplex harness into the 6 pin multiplex 8 track input harness, then you plug the 6 pin 8 track output harness into the speaker harness, and your done. I just don't have my Delco radio manual at work, so I can't check to see if there is such a thing as a 67 multiplex 8 track player. I'll check tonight from home. I can't remember ever seeing a 67 with a multiplex and an 8 track. I doubt I've ever seen more than one or two 69's besides mine with an 8 track and anykind of radio for that matter.

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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine
 
#6 ·
OK, that sounds right, but there's one problem..if the 8-track was installed at the factory and there were two different designes (one with multiplex and one without), how would the factory know which one to install since multiplex was only availadle from the dealer in 67? I doubt that the dealer would have to swap out the regular 8-track player for a different one when installing the mulitiplex. It would seem like a waste. Also, I have a dealer installed parts list and no where on it is an 8-track player mentioned either in base form or with a an AM/FM multiplex adaption. I just bought a 67 convertible that is trim tag coded 2U (8-track), has an AM/FM radio in the dash, the noise suppressor on the blower motor, correct, non-telescoping front antenna, and a cardboard cover under the inside dash speaker grill. There is a bracket under the dash that matches the one in the assy manual, but no multiplex or 8-track player around..so, I want to try to find out what was this original setup..

Thanks again for the assistance, Mark
 
#7 ·
I get the following part numbers for 8 track players:

7301001 67 and 68 Camaro Tape Stereo
7304161 68 Camaro Tape Stereo (A/C) (W/Console)
7305201 68 Camaro Tape Deck (W/Console)
7305211 68 Camaro Tape Deck
7305221 68 Camaro Multiplex Tape
7307811 68 1/2 Camaro Tape Player
7307821 68 1/2 Camaro Tape Player (Console)
7307831 68 1/2 Camaro Tape Player Multiplex
7307841 68 1/2 Camaro Tape Player Multiplex (Console)
91BT421 69 Camaro Tape Player Multiplex
91FT221 69 Camaro Tape Player

There is no 67 Camaro Multiplex Tape Player listed in the Delco Radio Service Manual. Dealers must have cobled together some other cars tape player system and adapted it to the camaro if thats what the customer wanted. There is a 67 Chevrolet Multiplex 8 track P/N 7300491. I don't have a picture of it (don't have the 67 Radio Service Manual). Dealer might have used that instead of a Camaro tape player.

Is your car a late production car? Maybe some 68 tapes were made available before the end of the model year.

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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine
 
#8 ·
Ok, thanks..I don't know..I give up..My car was built 2D. When I look at the bracket, I can see where both upper and lower mounting holes were used..I think I'm going to splice into the speaker harness and see what happends..all the other connections are simple using the fader as a changover device.So what you're saying is one couldn't get a multiplex in 67 Camaro?
Thanks Mark
 
#9 ·
You couldn't get one from the factory. Dealers used the Chevelle, Impala and Chevrolet multiplex adapter (the box with the 4 knobs on it) to give you the stereo output in the camaros. Combine that with the speakers from an 8 track setup and you get a multiplex radio system.

There wasn't a Camaro 8 track sytem that was compatible with this setup in 67. There might have been a buick, or pontiac unit that would work but I don't have the wiring diagrams, or pictures of these units. I know how to modify a Camaro non multiplex 8 track internal wiring to allow the multiplex to feed thru the 8 track unit to get to the speaker system, I just don't think a dealer would spend the time and effort to do this installation.



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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine
 
#11 ·
Gentleman,

Believe I have the answers to your questions. Although my time is at a premium, I find these posts interesting, as it raises new issues and ideas for my on-going research. I created the first and only on-line guide to the Chevelle audio world:
Radio Tech
as well as provided essential radio research material to Mr. Alan Colvin in his latest and greatest work "Corvette By the Numbers". I've also restored vintage GM radios. My research is always on-going, as I try to untangle the mystery that is stereo/multiplex/tape systems in post 1966 model year Chevrolets, focusing primarily on the Chevelle line.

To cut to the chase, yes I DO believe you could get the following in a 1967 Camaro;

An AM/FM stereo-multiplex radio AND an 8 track player.

This system literally was "thrown" together at the dealership when requested, and designed as an after-thought as far as the Delco engineers were concerned. Will post pictures of units (but not the installations) if/when I get the time.

This system utilized an ultra-rare switch. It was a small round "knob" that hung under the dash. It had a bracket that said "RADIO - TAPE". By turning the switch, you literally switch ALL of the power/speaker connections to or from the standard 4-knob multiplex control box OR the tape player which also had 4 control knobs to the 4-in vehicle speakers.

This was done to allievate dealer stress, this little switch linked "the two worlds". Both the traditional below-dash tape player and the below dash multiplex would normally not be founding "working" together, but they were out of necessity when the dealership needed to install a tape player when Am/Fm multiplex was already there. I've even seen an image in a dealer brochure (an artist's rendering mind you) showing something that totally blew my mind the first time I saw it. It showed the 4-knob MPX (multiplex adapter) STACKED! on top of the 4-knob tape player and the whole thing secured to the bottom of the dash.

I can not gurantee my findings 100%, however I just consulted my Sams Photofacts and my 1967 Delco manual, and the evidence seems to support what I have said. I do have a saved image of the rare mpx/tape switch (somewhere in my mounds of floppy disks of radio images!). The switch DOES exist, although I can not say it was used in a Camaro personally. Finding this switch is next to impo$$ible. If I ever find one, I will not sell it.

Interestingly enough, the Chevelle line (thus far) appears that if one ordered a am/Fm radio with multiplex stereo AND requested an 8-track player, the factory did a NICE job, thus installing a model 7300491 multiplex stereo adapter INSIDE the dash (this unit has no control knobs) and was linked to both the am/fm radio AND the typical 4-knob 8 track player (7300481) via cables. When the radio was tuned to an FM-stereo station, an indicator lamp IN THE 8 TRACK lit up "FM STEREO" controlled via the "hidden" mpx box (7300491). When an 8 track tape cartridge was inserted in the tape deck, the internal switch mechanism disabled power to the radio and mpx adapter as well as disconnecting the speaker loads from the radio's output and "reconnecting" them to the 8 track's output. Power was also applied to the 8 track, causing another indicator lamp on the 8 track to lite "STEREO TAPE". What was nice about this set-up was it took advantage of the technology (after all, it was FACTORY specified/installed) and required no manual human interaction when playing tapes (no little switch to switch under the dash).

I hope this helps. Please do not take everything as gospel--yet, I'm still doing confirmation work. The research on this "stuff" is very rewarding, yet tedious and time-consuming. I ask that you please do not e-mail me due to time constraints of already answering many, many radio questions for others.

Joe Hubka
 
#12 ·
Great input Joe thanks, that very interesting reading. Keep up the good work.

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.... Click aka Jim .. Cylinder Index = 35
Dover White 69RS 350/255 LM1, TH-350 auto., A/C
Blue Vinyl top, F&R spoilers, 3.08 Eaton Posi.
fold down rear seat, PDB, PS, Cowl Induction, Endura Bumper
My RS.. www.brainerd.net/~knudsen/69RS
 
#13 ·
Hey Joe! WOW! what an interesting observation..I think my car one of these "rare" combinations of multiplex mounted on top of 8-track..The thing that gets me is that this switch you say that is mounted under the dash..doesnt it do the same thing as the fader switch on the tuner knob of the radio? Do you have the part # of this switch? Could it be 987072? The thing that still intrigues me is how the 3 speaker harnesses came together? (one from 8 track, one from multiplex and one to speakers..I know that when an 8 track cassete was placed in the unit, an internal switch killed power to the radio and I thought the fader switch transfered the sound from multiplex to 8-track..I don't know..One last thing..I have a strange swich that came with a 67 Camaro wiring harness I aquired years ago..I wrote it off as a full size Pontiac switch for something..it has the identical wiring/connector set up as the fader switch, but the wiring from the switch to the connectors is approx. 1' long..BUT, it's a 4 position switch??? I'll take a pic of it and post it here tomorrow..maybe someone will recognize it..

THANKS again..GREAT info!!!! Keep up the great research
 
#14 ·
Originally posted by 1967 Panther:
The thing that gets me is that this switch you say that is mounted under the dash..doesnt it do the same thing as the fader switch on the tuner knob of the radio?

Panther, no, the fader control simply directs the full output power from the radio's output circuitry to 2 speakers (the front and the rear) and allows you to adjust to your tastes. The switch I speak of, has interconnect harness that "redirect" power and connections to all speakers whatever is currently in use (either the 8 track or the am/fm-stereo radio).

Do you have the part # of this switch? Could it be 987072?

I have some cool pictures and model number(s) of the switch, the bad news is where?! I'll have to dig thru my computer files this weekend perhaps.

The thing that still intrigues me is how the 3 speaker harnesses came together? (one from 8 track, one from multiplex and one to speakers.

Again, I'll try to post somethings later on


I know that when an 8 track cassete was placed in the unit, an internal switch killed power to the radio and I thought the fader switch transfered the sound from multiplex to 8-track..I don't know..

The fader switch didn't transfer and signals from radio to 8 track. There are (2) different things when it comes to faders. The traditional fader (the "slip-on" as I call it) was used ONLY on mono (non-stereo radios). This sat behind the tuning knob of the radio and controlled how much power was dissipated by the front or rear speaker. If you had an 8 track used in conjunction with a mono radio, there were wire provisions in the 8 track that allowed this fader on the radio to control the rear speaker (as it should). Once the 8 track was activated, the connection was OVERRIDDEN by the 8 track switch, and allowed the 8 -track's own fader to be used.

Stereo radios had fader apart of the MPX box. NOT on the radio itself (this of course changed in '69 as technology improved). 8 tracks also used with stereo radios (what this post is all about) also had faders (labeled "FRONT-REAR") to control their output. It all depended what was ordered, this dictated what specific 8 track, MPX and radio equipment model numbers were installed in a particular vehicle.


One last thing..I have a strange swich that came with a 67 Camaro wiring harness I aquired years ago..I wrote it off as a full size Pontiac switch for something..it has the identical wiring/connector set up as the fader switch, but the wiring from the switch to the connectors is approx. 1' long..BUT, it's a 4 position switch??? I'll take a pic of it and post it here tomorrow..maybe someone will recognize it..

Not sure, it may be a Buick/Olds/Pontiac selectable REVERB control.

Also, a typo in my first post, the Chevelle system used a 7300471 tape deck when interconnected to a hidden mpx control, not a 7300481

Joe
 
#16 ·
The 68 and 69 Camaros (with a console) all have an 8 track player with 4 knobs on the front of the player mounted on the console with the front of the player facing forward. There are two different types of 8 track players used in these years one for use with a mono radio, and one for use with a multiplex radio. The difference is in the number of wiring harnesses connected to the player. The multiplex units have an extra set of wires to connect the stereo output from the multiplex radio to the 4 speakers in the car, while the mono setup didn't need these wires since the 8 track speakers are totally separate from the radio speaker in mono cars.

68 Camaros equipped with a multiplex radio, but no 8 track player had a 4 knob control unit for the multiplex radio mounted in the console cover.

67 8 tracks look basiacally the same as the 68/69 unit but they sat on the front of the console, or in a bracket on the floor under the dash on top of the transmission tunnel, and have the heat sink built into the back of them, unlike the 68/69's which have a separate heat sink that is mounted up under the dash.
 
#18 ·
Okay guys. This thread was great for me in my search for all the correct components for my car (having an 8 track, multiplex and am/fm stereo all together). My car came factory with the 8 track and AM/FM Radio. The "Ultra Rare Switch" that connects the 8 track, Multiplex and AM/FM Stereo all together, does exist, because I have one that I located that is still in the original box. This switch was the last of the original components that I needed. If you need any pics of it let me know and I will send them to you. So to answer the final question, yes this switch actually exists.

Bruce.
 
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