Technical Hidden Bluetooth Sound System Install [Non Invasive]

If you are only interested in bluetooth connectivity from your phone then I would suggest using the Blaupunkt amp (or some similar type of amp). I installed mine in the trunk and ran a power cable and remote wire from the front of the car for the amp. Amp comes on when the car starts and the phone automatically connects.


https://www.amazon.com/gp/product/B08H7DR56W/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

The Amp is in the 1st post .
There is a link.
I connected 2 dedicated speakers on the parcel shelf directly to the amp.
My 57 radio has it's own speaker on the dash which has not been tampered with.
If I was to do this again, I would mount the Amp under the seat or parcel shelf and forget about the Aux input.
Bluetooth from the phone is good enough for my needs.

 

Great write up, going to have to use this amp on the '28. Phones are a necessary evil to me (I'm steeped in tech, but just don't care ), so old base model (low gbs) phones with a very low data plan and major music taste (70g and growing) means I own older iPods. Every car has it's own and the '28 will be the same, just picked up another 160g at the swapmeet for $5.

 

If you're a bit more handy with the soldering iron, I bought a tiny little board that has a passthru relay on it- turn the phone off and it disables the relay, allowing the original radio reciever to feed the power amplifier stage.
Enable it and it switches automatically to the Bluetooth, and that plays out via the power output stage instead.
No forgetting to switch it over. Only forget to switch the radio off... But that's a given.

Can even pull the board out, move one wire and the radio is back to standard.
You can't even see it, even eyeballing up under the dash, the radio has to be physically taken apart.

You even gotta wait for it to warm up.

 

@PhilA could you give a little more information on what you did? Maybe the circuit board info?

How does the phone control the relay?

 

I left that kinda vague but this is the board I used.
https://www.ebay.com/itm/403575058520
Standard 1V p-p input/output (line level), isolated from the circuit with a capacitor; I associated my phone with it. It does have a connector for an external antenna but I found the vent holes on the radio case to be large enough to allow Bluetooth radio through.
When the board powers up by default it's in passthru mode. When the phone connects to it, click. Audio from the Bluetooth is engaged and the radio reciever audio is disconnected automatically. Switching Bluetooth off on the phone puts the AM back on.
Only thing it can't do is process a phone call. If my phone rings, it disconnects.

Phil

 

Please clarify “door relay switch” as is this a relay named as such or just a standard 5 pin relay you’ve added in? Thanks

 

I used a standard 5-pin relay that powers the sound system from the 12v continuous side of fuse box.
This relay is activated on the primary side by the accessory side of the fuse box.(with ignition on)
I added a loop wire from the output wire to the primary circuit so it stays on when the ignition is switched off.
I added another relay in series to this loop wire (reverse post 87A) and connected the primary circuit to ground at a door switch
Once the door opens the relay switches to post 87 and disconnects the loop wire.
The ignition must be switched on again (for a moment) to re-activate the relay
The door can also be opened when the ignition is on and the relay stays activated by the ignition.

There was a few backfeed issues because the Chevy ignition switch shows continuity between the coil and the accessory circuit.

I post a schematic if you want one

 

No need for how you wired it. I just completed a buzzer set up using only one relay. With blue tooth on (switched hot) and ignition on, buzzer will not sound if doors open or dome light switch is used while car is running. Turn car off and forget to turn off blue tooth then doors or dome light switch will trigger buzzer. This was done by, buzzer red wire to switched hot for/from blue tooth, buzzer white wire to #87a terminal of relay, ignition switch on to relay coil #85terminal, ground wire to #86 terminal and door jamb wire to #30 terminal.