Hardwiring Bluetooth 5v-24v module internally to a 2220B

CrazyEye

CrazyEye

New Member
First post on here!
I'm sure many of you will cringe at the fact of adding bluetooth to a vintage receiver

However I've been wanting to do it for quiet some time now, I just recapped the entire receiver and had a lot of fun doing it. Everything is running right and voltages are in spec (or close enough) on the power supply board

My main idea was to go off the 14v J808 pin on the power supply and feed it straight to the module with a ground being literally anywhere with 3.5mm to rca spliced and soldered to the input of the aux rca internally then mounting the board to the metal chassis with some insulation to prevent any possible shorts to chassis..

However during my basic test to see if it actually works, the 14v J808 reads fine (13.5v) but when I attach the alligator clip feeding into the BT module the voltage seems to cut off every 3 seconds, I thought maybe it was the BT module turning off but when I put my meter to the actual J808 pin, the power supply it self seems to be interrupting the power. I'm assuming this is some kind of protection integrated into the power supply itself.. Would anyone have a recommendation on where I could get steady 5-24v DC from inside the unit itself?

Has anyone actually hardwired bluetooth to this particular amp or one similar to it?

I'm very new to vintage audio gear and the recap was the first time for me.
Online I found a few DC voltage outlets but 14v from J808 was the lowest I could find and it seems to be turning itself off :(
 
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I plugged a BT transmitter into my 2325 headphone jack and paired it with a BT speaker for use on my patio. Worked fine.
 
wurlyman said:
I plugged a BT transmitter into my 2325 headphone jack and paired it with a BT speaker for use on my patio. Worked fine.
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I wanted to wire in a BT receiver to accept BT from the phone or whatever I'm using to connect to. Transmitter would make sense to have BT speakers work but I want to do it in the opposite way, so I could send music to the receiver and have it play through to the wired speakers.
 
I thought about adding a Chromecast Audio to the inside of a Kenwood integrated amp but ultimately decided it was too much trouble. I think your best bet would be to add a small dedicated power supply circuit board and connect the mains side to the interior portion of the switched outlet on the back of the receiver. The power supply could introduce additional noise into the other circuitry, so it may need shielding. You may also run into problems with the BT signal being blocked by the metal case of the receiver.

I'd be wary of performing such a mod on a classic like the 2020B, but it could be fun on a cheaper amp/receiver that you don't mind hacking up a bit.

Alternatively, you could just plug the BT module's power adapter into the switched outlet on the back of the receiver so that it powers on when you turn the receiver on, it's a little clunky, but most BT receivers are so small that they can hide behind a receiver no problem.
 
CrazyEye said:
I wanted it inside, less clutter and I wouldn't have to plug it in. If I move my receiver from one place to another, it'll be all contained.
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If you simply must mount it inside, I second the notion that you will probably have to add a separate power supply for it as well.
 
zaskarx said:
I thought about adding a Chromecast Audio to the inside of a Kenwood integrated amp but ultimately decided it was too much trouble. I think your best bet would be to add a small dedicated power supply circuit board and connect the mains side to the interior portion of the switched outlet on the back of the receiver. The power supply could introduce additional noise into the other circuitry, so it may need shielding. You may also run into problems with the BT signal being blocked by the metal case of the receiver.

I'd be wary of performing such a mod on a classic like the 2020B, but it could be fun on a cheaper amp/receiver that you don't mind hacking up a bit.

Alternatively, you could just plug the BT module's power adapter into the switched outlet on the back of the receiver so that it powers on when you turn the receiver on, it's a little clunky, but most BT receivers are so small that they can hide behind a receiver no problem.
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That was my ultimate plan b. Taking an old phone charger and soldering the leads to the inside of the AC switched outlet and running a micro usb. shielding it would be very important. I was hoping there would be a positive line I could tap into and easy peezy, install complete. These old receivers are a whole different breed and respect is needed for these guys. I'm probably going to just accept defeat and not botch up a perfectly working/restored 2220B just for BT. Thanks for your reply zaskarx
I'm still open to suggestions if anyone has some info on finding an appropriate positive DC line lol
 
I added a Miccus RTX so I can do either transmit or receive. External because I will NOT add modern gadgets to the internals of a vintage Marantz!!! NO WAY!
Now the Blaupunkt in my 1966 VW is another matter. I had a BT transreceiver made by Aurora Design added to it. But I will NOT Mess with a Marantz!
 
I wonder how well a bluetooth module will receive inside a metal cabinet. I doubt it would work at all. (cabinet blocking bluetooth signal)
 
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I make up a bluetooth rig for some of my customers. I use a small 5 volt USB charger plugged into the switched AC outlet, with a bluetooth adaptor plugged into the USB, and a short stereo 3.5 mm to RCA adaptor going to the AUX or tape monitor on the receiver or amp. The bluetooth adaptor works, because it is outside the metal case..
 
zaskarx said:
Alternatively, you could just plug the BT module's power adapter into the switched outlet on the back of the receiver so that it powers on when you turn the receiver on, it's a little clunky, but most BT receivers are so small that they can hide behind a receiver no problem.
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This. This is an absolute perfect use of the switched outlet on the back. Use it for a low powered device such as a bluetooth receiver, Chromecast audio, etc.

It's amazing how these old receivers integrate in perfectly with modern technology. On my 2238B that I have in my basement, I can run a chromecast via the switched outlet and the Aux In and use the Pre-outs for a small powered subwoofer. Heck, many modern amps aren't as flexible as this.
 
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