FM Radio rear speaker volume/reverb knob location

Ben Herman

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I just got word from the guy repairing my FM radio that it was a relatively quick fix and is now up and running. My car came with an AM radio so I don't know where the knob goes that controls the rear speaker volume/reverb. I assume some drilling will be needed if it goes in the dash. Does anyone have this installed that can grab some pics? Measurements to things to help me dril in the correct place if needed would be great as well.

Thanks,
Ben
 
The control knob is mounted on the bottom of the dash below the radio. My recall is that the reverb unit is mounted behind the rear seat back. At least that’s how it was on the 1966 300 4-door that I used to own.
 
Directly below the radio, at the bottom of the dash.

Cars could have simply a rear seat speaker option, OR the rear seat speaker and reverb option.
 
reverb unit?
I used to have a factory reverb in a 1960 Pontiac many years ago. From what I remember, the reverb delayed the sound to the rear speaker 1/10th of a second and created an echo so to speak. It was pretty neat until I went over a railroad track or bumpy road causing it to vibrate way too much.
 
Not sure if 66 and 67 are similar but the reverb unit (the box) goes under the rear seat and is screwed onto a bracket there. In my 67 300 I have the AM/FM radio and the reverb unit is turned on with a toggle that is just to the right of the power antenna switch. See photo, the toggles left to right are map light, p antenna and REV for reverb. Cam Shaft

IMG_0194.JPG


IMG_0215[1].JPG
 
Interesting!

65/66 reverbs use a fader knob to dial in the back speaker balance, and then you pull down on that same knob to engage the reverb. Reverb tank was mounted under the rear package tray between the speakers.
 
To the left of the drawer. Sort of under but just to the right of the ignition switch. So I guess it's a bit to the left of the radio... sorry! :)
There's no switch here in this photo, but you can see where it would go. Mirroring the placement of the two toggle switches on the left side of the steering column.

kilo dash in wagon 2.jpg
 
Here's what I have. Am I missing a trim piece? Also if anyone knows where that red wire goes I'd love to know. It comes off the knob.

View attachment 580437
I looked at the '66 FSM and on page 1-20, there's a diagram that shows red going to power. I was kind of surprised I didn't see a more complete wiring diagram, but maybe it's hidden in the other wiring diagrams back in the electrical section.

Don't have a FSM (factory service manual) ? Download one here: Service Manuals – MyMopar

Now I need to look for a reverb wiring diagram because I'm curious.
 
Did find this from Radio and Accessory Repair Information for Chrysler Imperials and Imperials

While that site isn't the easiest to navigate, there's a lot of good info, and not just for Imperials.


IMPORTANT

OPERATING INSTRUCTIONS FOR REAR SEAT RADIO SPEAKER EQUIPPED WITH REVERBERATOR

Your new automobile is equipped with a factory installed combination Rear Seat Speaker and Reverberator unit which produces outstanding sound reproduction.

How it Works: To simulate "music hall" acoustical effects, audio waves are delayed by an Electromechanical delay line and reamplified after 20 to 30 thousandths of a second. The final output is unique and of distinctive quality.

Reverberator Control: The Reverberator is controlled by a push-pull knob located near the radio. To turn the Reverberator "ON", pull the knob out. To turn the Reverberator "OFF", push the knob in. With the control knob in the "OFF" position, normal speaker performance is obtained without reverberation. Adjustment of the volume "mix" between the front and rear speaker is obtained by rotating the control knob. With this built-in fader control feature, the rear speaker control ring, located behind the right radio knob, is no longer used for mixing between speakers.

NOTE: The radio and the Reverberator are separately operated power units. When the radio is turned "OFF", the Reverberator should also be turned "OFF" by pushing the control knob in.

INSERT THESE INSTRUCTIONS IN YOUR OPERATING INSTRUCTION MANUAL​

Part Number: 2497388 - - - - - - - - - - - - - - - - - -
 
That's definitely a 65/66 Plymouth Dodge Fader/Reverb switch. Turns L/R to balance front to rear, and pulls down to turn on the reverb.

There will be a harness that goes to the reverb tank from the switch. The red wire goes to a Key On power buss at the fuse box.

Yes, you are missing a bezel for the switch... typically says R Speaker. I'll try to get a pic of mine and post it. FWIW, your switch's knob and bezel aren't technically correct for Chrysler.
 
I looked at the '66 FSM and on page 1-20, there's a diagram that shows red going to power. I was kind of surprised I didn't see a more complete wiring diagram, but maybe it's hidden in the other wiring diagrams back in the electrical section.

Don't have a FSM (factory service manual) ? Download one here: Service Manuals – MyMopar

Now I need to look for a reverb wiring diagram because I'm curious.
You'd think I would have thought of checking the manual. I have a paper copy sitting on the bookshelf. That explains why the reverb hasn't worked so far. The diagram does add to the confusion as to where the knob is installed.
 
That's definitely a 65/66 Plymouth Dodge Fader/Reverb switch. Turns L/R to balance front to rear, and pulls down to turn on the reverb.

There will be a harness that goes to the reverb tank from the switch. The red wire goes to a Key On power buss at the fuse box.

Yes, you are missing a bezel for the switch... typically says R Speaker. I'll try to get a pic of mine and post it. FWIW, your switch's knob and bezel aren't technically correct for Chrysler.
That certainly adds to the confusion. I understood the radio I have *only* fits a 66 Chrysler. Do you think the knob was swapped or is it just that no Newport would have had one?
 
Any radio could be optioned with reverb, not just Chrysler radios, as far as I know. Some Chrysler radios, especially the search tuner radios had wider knob spacing than standard radios available in both Chrysler and other cars. It actually resulted in 6 different radio dash plates for Chrysler alone... I bet the bean counters missed that one...

You can see the radio rear speaker switch just to the right of the ignition switch and to the left of the power antenna and map light switch in my 66 Canadian Monaco. In case you didn't know, Canadian Monacos used Plymouth dashes in 65 and 66. This particular car was ordered radio delete, and a Chrysler search tuner radio and power antenna and reverb system were installed at the dealership (long story). Holes were drilled for the shafts using the factory template, RIGHT THROUGH the radio delete cover!! LOL...

RADIO SPEAKER FADER SWITCH.jpg


More pics 004.jpg
 
Any radio could be optioned with reverb, not just Chrysler radios, as far as I know. Some Chrysler radios, especially the search tuner radios had wider knob spacing than standard radios available in both Chrysler and other cars. It actually resulted in 6 different radio dash plates for Chrysler alone... I bet the bean counters missed that one...

You can see the radio rear speaker switch just to the right of the ignition switch and to the left of the power antenna and map light switch in my 66 Canadian Monaco. In case you didn't know, Canadian Monacos used Plymouth dashes in 65 and 66. This particular car was ordered radio delete, and a Chrysler search tuner radio and power antenna and reverb system were installed at the dealership (long story). Holes were drilled for the shafts using the factory template, RIGHT THROUGH the radio delete cover!! LOL...

View attachment 580448

View attachment 580444
Well hearing about the spacing is pretty worrying. I sure hope mine fits. I have over $500 in it so far...
 
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