Car audio via Bluetooth FM adapter

[MilkyNoSugar]

I know I will not use the radio too much, and its sacrilege to some fitting a dash cam, phone mount and Bluetooth adapter to a classic car, but I have always done something similar in all my weekend sports and classic cars so far. It is occasionally nice to have some music on a long journey and I can also then use hands-free calling and audio instructions for the phone without replying on the phone speaker and mic.

Bit of a result tonight and I found I can successfully tune the original radio into a small Bluetooth FM adapter and then stream audio and calls from my phone. I have one of these in my other car so thought I would try it.

Avantree CK310 Bluetooth FM Transmitter with built in mic

https://www.amazon.co.uk/dp/B07TMYSXL8?psc=1&smid=A2JYKDL02CLV4Y&ref_=chk_typ_imgToDp

I already have a Quadlock phone holder with wireless charging and a dashcam and both just need USB power.

I will also use a small 12V to 5V 3A 15W Power Adapter to power the phone charger, BT FM adapter and dashcam. This can be hidden out of the way.

https://www.amazon.co.uk/dp/B08W21WSTH?psc=1&smid=A19VQ1SN4ZXLJG&ref_=chk_typ_imgToDp

Where is the best or easiest place to pick up a 12v live feed and earth in the cabin area, ideally under the dash or centre console? It needs to be live with the ignition rather than live all the time.

I do only appear to get sound out of the passenger speaker. I am not sure if the car even has two speakers under the dash or even if it's a stereo radio. I had read somewhere that stereo radios had the word stereo on them and mine does not as far as I can see. Before I start taking things apart, is stereo standard or an option on a 72 C3 convertible?

Any guidance is appreciated.

 

[teamzr1]

Refer to the RPO label in your car and the GM PDF book I gave you shows what the features and options were
U79 was with stereo
U69 did not

 

[MilkyNoSugar]

I had already looked at the manual and could not see either U69 or U79 on the Corvette order form that came with the car. There is a UL5 code and the rest of the text is unreadable. A quick search online suggests it is a Radio Delete code though so that's no help and implies the radio is an upgrade fitted at some point in the last 50 years.

The more research I am doing, the more I am sure it is a stereo radio, so expect I have a faulty speaker.

The radio looks like this

 

[teamzr1]

There should be a build sheet on top of the gas tank, might get to via behind rear license plate

If stereo, I would think the faceplate for the outer knobs would show as to adjusting left / right balance

 

[MilkyNoSugar]

I know the gas tank has been replaced by the previous owner. I expect the tatty-looking ad heat-damaged bits of paper I have in the folder may have come from there.

I have tried adjusting the two outer rings and they seem to change the tone/bass/treble rather than switching the balance. Even with a faulty speaker I would have expected the 1 working speaker volume level to change if the balance is working as expected.

Not a massive issue on the speakers.

The bit I could do with some guidance on is where to pick up a switched live and earth from. I have not found the fuse box/board yet. Where is it?

 

[teamzr1]

Looks like you have a mono radio, so only 1 speaker
If stereo, other speaker on right side



Fusebox on the firewall, up there where you can't even SEE it, above the driver's left toes above the dimmer switch

Not sure but this could be correct

Left side, starting at the top:
First slot is empty!
CLK LTR CTSY (courtesy lights and cigarette lighter , and clock)
TAIL LPS
STOP HAZ
little tiny fuse, lower left: INST LPS

on the right side, starting at the top:
WIPER
HEATER A/C
RADIO
DIR SIG BACK UP
GAUGES

In the middle are 3 "outlets" or plugs, labeled, top to bottom:
BAT (gives you continuous power "from the battery")
ACC (gives you power only when key is in the ACC position or on) here is switched power
IGN (gives power only when key is in the "on" position)

Look at attached wiring drawings PDFs

 

[MilkyNoSugar]

that is great. I really appreciate your help

 

[MilkyNoSugar]

So, I completed this job over the weekend and I am pleased with the results.

I fitted one of these USB power adapters in the cavity behind the outer footwell side panel. I picked up a live IGN feed from the fuse box and fitted an inline fuse. I got an earth from the metal birdcage (assume that's the right name for it) .


AITRIP 2 PCS Double USB Car Converter Module 12V to 5V 3A 15W Power Adapter DC to DC Reduced Voltage Regulator Car Power Converter Output Power Adapter

I then ran USB a USB cable in the gap behind the dash side panel on the drivers side and brought it out near the a pillar to mount one of these Bluetooth FM transmitters on the dash, tucked right in the corner behind the A pillar.



Avantree CK310 Bluetooth FM Transmitter for Car, Wireless Radio Adapter Hands Free Car kit with Magic Tape, Auto Power On Off with Car
https://www.amazon.co.uk/dp/B07TMYSXL8?psc=1&ref=ppx_yo2ov_dt_b_product_details
Tuned it and the radio to the same frequency and can play music from my phone, satnav audio and get audio calls through its built-in mic and radio speaker. The sound quality is not great but it's okay.

From the passenger side I ran a USB cable up the up inside of the dash, up the A-pillar, across the top of the screen to the dash cam mounted behind the mirror. A second USB cable, up the dash and across the dash, but tucked into the gap between the dash top and dash front to power my quad lock phone charger which is mounted on the screen and to the side of the wiper switch.

No visible cables apart from the last few cm.