gratsoy

I bought a two-piece AM/FM radio for my 70. I do not have a rear speaker in this car, and don't intend on installing one. I am wondering if I can still use this radio? Could I simply not install the multiplex unit and instead only install the dash unit?

Yellowstatue

Make sure the speaker fader is all the way to the front speaker.

gratsoy

Do you think I would be able to completely omit installing the multiplexer unit if I do this?

Yellowstatue

I think so, but not 100% sure.

rcorrigan5

I believe that, without the multiplex unit, you will only get half of the sound because it's a stereo unit, and only half of the sound will be hollow. Here's a better bet - you have a wonderful set-up that someone would most likely pay a good price to get. If it were me, I would try to sell the stereo radio/multiplex unit you have and look for an AM/FM mono radio with or without the fader dial on the right side. An AM/FM radio without the fader will give you what you want now and it gives you full sound on the front speaker. If you get one with the fader dial and the blue rear speaker wire, you still get full sound on the front speaker with the dial set to "front" and it gives you the option of perhaps installing the wiring and a rear speaker, which would give you full sound on both speakers.

I have a factory AM/FM mono radio with a rear speaker installed on my '68 4-4-2 (originally came with just an AM radio/front speaker only) and it sounds great, considering what you got in that day. I have an AM/FM stereo radio (complete with the multiplex unit) that originally came with my '69 4-4-2. To me, the radio in the '68 sounds much better than the stereo unit in the '69. I'm thinking that the technology back in that time for stereo was still somewhat new and it just seems to me the stereo reception is just not as good as just receiving the FM signal and getting full sound on both speakers.

Randy C.

gratsoy

I have heard the same from other people regarding the sound quality. I originally bought the multiplex unit because I wanted the correct 1970 radio - I wasn't aware there was a mono version for '70. I'll have to dig.
I will likely need to let this one go and get a proper unit. This was professionally restored, so hopefully I can find something similar.

Is the multiplex truly stereo sound? I was wondering if it was just a dual mono set up? Seems odd to have the right channel come out from the rear of the car.

RandyS

Yes, multiplex was the first commercial version of FM Stereo. I agree, stereo front and back is not really discernable by the human ear, it needs to be side to side to be really effective (unless you can somehow ride with your head turned.........)

gratsoy

Interesting. Were FM mono radio's even an option? I might have to stick with AM...

rcorrigan5

Good point about if the AM/FM mono was even available for the '70 model year. I don't see it listed in the publications that I have. I do see it as a U69 option for '68 and '69 (of which one would have had to order the U80 option if they wanted a rear speaker, too) but I don't see it for the '70 model year.

Randy C.

Rocketbrian

There was a 2 piece stereo unit in 70, a one piece stereo unit in both 71 and 72 and a one piece mono unit in 72. The faces all looked identical except for the lack of a "stereo" light in the 72 mono version. The mono unit was much cheaper to buy than the stereo version, most likely why it was offered. That may be the most suitable radio for your purposes.

Yellowstatue

Cutlass AM/FM was available in '67.

RetroRanger

maybe you could use a dash speaker like this for the stereo sound

https://www.crutchfield.com/learn/bl...ar-owners.aspx

gratsoy

Only issue is that the olds uses high resistance speakers - I think 10 ohms? So this would damage the radio.

I think I will locate a 72 mono FM unit and put my multiplex unit on the Classified board.

VC455

Garrett, the Vista Cruiser radio options for 1970 were U63 Deluxe Pushbutton Radio (this is the AM radio) and U58, the unit you bought.

And, as already noted, you cannot modify the multiplex radio so that only one channel is used. The main radio portion has two amplifier circuits and if you don't attach a speaker to the second circuit, you will damage that circuit.

Would it be an option for you to put a speaker under the front seat?

Best wishes,
Gary

gratsoy

There's certainly a lot of options to make this work - but at the end of the day I'm would be just rigging the radio up to work how it wasn't intended for my car.

The 72 Mono unit is a good option - while 2 years newer, it does match the proper appearance for my car. Plus, it's not un-reasonable to assume that some cars back in the 70's had one of these installed at the dealer when the owner wanted to upgrade to FM from their AM radio.

VC455

With the same logic, I put a 1971 stereo FM (no separate multiplexer) into my Vista Cruiser.