I would like to add a bluetooth receiver like this to the 9 Int 1 as it seems to be the simplest solution.

The radio has a phono jack and a tape jack. 

My first question is, which jack is the preferred jack to connect to?

If the phono jack is preferable, what type of cable should be used as the phono jack is not a modern RCA jack.  A modern RCA cable does not connect to it properly and the jack is just one input, not 2.  

If the tape jack is preferable, would a din3 cable work?

And for both jacks do I have to be concerned about the receiver being stereo and the radio mono?

Thanks for any help,

Mark

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Dear Mark,

It doesn’t matter if you use the phono input or the tape input. Both inputs end up to the same amplifier input. Phono would be somewhat easier as you have to press just one key Phono. For this input you can use simple banana plugs. I assume that the 3.5mm audio input is in reality the audio output of your Bluetooth device. I'm not sure if the output is stereo. If so, you have to join the two channels by using two resistors of approx.1.8 kOhm and connect it to the hot socket of the phono input.

I hope that helps,

Regards, Rolf

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Thank you Rolf.  I found a DIN cable that may work with the tape input.  

It appears that the phono input jack may work with a banana plug, but it doesn't seem like a solid connection.  If need be, I'll try that.

Thanks for your help,

Mark

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A follow up question.

I was able to use a DIN connector to connect the bluetooth reciever to the radio and I am able to transmit from my phone to the bluetooth and it plays well throught the radio.  The only problem is that I have to turn the radio up quite loud to get a volume level that I can listen to (the volumn on the phone is at maximum).  Is there a way to improve that?  Would the stereo to mono resistor suggestion that was made solve the problem?

Thanks

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Dear Mark,

You can try and bridge the two resisters, but I don't think it will increase much the volume.

Did you tried the phono input via a banana jack too?

Regards,

Rolf

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Thanks, Rolf.  I haven't tried the banana plug but I did try a different bluetooth receiver which didn't have the low volume problem.  Not sure why, but I'm considering this problem finished.

Mark

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Hello,

here I want to show you my solution for adding Bluetooth.

If somebody is interested, I can sell Kit´s für 19,-€ each Kit + shipping

Please watch my YouTube Video here:

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Thank you Matthias.  Your solution looks elegant and very similar to one I just ordered parts for as described in a video by Manuel Caldeira at Electronics Old and New on Youtube.  You can search his site for this video to see his solution.  I have ordered his boards and am waiting to receive them.

PCBWay PCB's for Tube Radio Bluetooth Module

I appreciate your response and the work you've put into your solution.

Regards,

Mark

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Yes he uses  the same dc/dc Converter, but he does Not habe a pre amp (for the same Volume in FM and Bluetooth) and He also Don t have Automatik Switch for the dc Converter & Bluetoothmodul.

The DC/DC Converter makes noisy in AM Bands and someone Times also in the FM band.

you can use a microswitch for his Modul to be switched on only when the pick up Button is Pressedienst.

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You have done a very nice job with this.  I particularly like the preamp. I will keep your kit in mind as I work on more radios.  

Mark

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