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Old School Alpine 7390 Bluetooth Input?

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
Printed Date: December 01, 2021 at 2:46 AM

Topic: Old School Alpine 7390 Bluetooth Input?

Posted By: FlyinHawaiian
Subject: Old School Alpine 7390 Bluetooth Input?
Date Posted: January 30, 2020 at 6:01 PM

Hey all,

I haven't played around with Alpine decks from the 80's since the 80's! Just got a 7390 head unit, new old stock, and now trying to install in an old Supra from the 80's. Looking for that period-correct setup (including using my old Proton 271 eq and the last 8" Collins USA B8 sub box I have layin' around!).

Question is, this unit has cd input (but no aux input), the old style 8 pin din (m-bus). Just looking to get an audio input to the stereo from a bt adapter for phone connectivity, anyone have an idea on an adapter that would give me either rca inputs, stereo 1/8" input, or even a complete bt adapter input to that din plug?

AI bus is a no-brainer, but I cannot find anything for this stereo. Shame too, as it was a phenomenal head unit for its time and still holds up to the majority of head units today. Would really hate to have to go the bt cassette adapter with this setup just to have my music play from my phone.



Posted By: feklio
Date Posted: April 16, 2020 at 4:01 PM
I had this unit back in 1989 along with the 6 Disc changer, It was Alpines top of the line unit at the time.


Posted By: i am an idiot
Date Posted: April 16, 2020 at 6:58 PM
Do you have a working M-Bus changer? If you do, I can dig up some notes and we can make this happen. If I remember correctly there is a shielded red and white cable in the larger cable. These were left and right audio coming from the changer. It is a matter of running those 2 wires out to a DPDT toggle or rocker switch. Common terminals back to the din plug, connect phone or audio from bt adapter to the other input of the switch. Switch in one position you are listening to the CD from the changer, other position will be your phone. You will have to run shield out and connect it to the shield of the bt adapter or cable coming from your phone.

Posted By: i am an idiot
Date Posted: April 16, 2020 at 7:07 PM
I am pretty sure that unit would not switch to the CD without a changer connected. If I am wrong about that, search fleabay for 3.5mm Jack AUX 8Pin M-BUS Audio Input Adapter Cable for Alpine

Posted By: FlyinHawaiian
Date Posted: April 17, 2020 at 9:13 AM
Hey all,
Thanks for the replies! I do have an m-bus changer, still brand new in box (a 5952 changer), but I was hoping not to have to install it in the car and switch between the two audio inputs (BT and changer via a switch).

I've searched around quite a bit on the m-bus data line and it is possible to link an input to the deck without a changer, but it requires building a small pc board and doing a bit of programming to make this board "talk" to the old 7390. In case anyone else is reading this thread and looking for info on how to do it, this link has a fair amount of info on the m-bus protocol and how to make an adapter to work:

For now, I'm using an BT cassette adapter that works okay, its not the best sounding connection but it allows me to listen to my music on my phone and that's really all I need. The Supra is really just a weekend cruiser and for going to car meets, so this works for now.

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