Bluetooth receiver to old cassette player - UK Vintage Radio Repair and Restoration Discussion Forum

Lef de art · 22nd Mar 2024, 4:21 pm

Good evening guys.
I want to install a bluetooth receiver on a 1970 tape recorder. The problem is that when I use the internal cassette player power supply on the Bluetooth receiver there is a Very loud hum in the speakers. The Bluetooth light turns on but the hum is that loud that i can hear nothing at all!
It sounds like i connect dc voltage to the sound input!!! This does not happen when I use an external power source on bluetooth. However I would like to use the internal transformer of the cassette player and not add a second one. Does anyone know if I can do something to the bluetooth power supply with a circuit? Thanks in advance.

I use the correct dc voltages in both cases (internal or external power supply)

Lef de art · 22nd Mar 2024, 11:41 pm

And the problem is solved by using a B1212S-1W (isolated dc-dc converter 12v) .
Hope my post will help other similar situations.

Nickthedentist · 23rd Mar 2024, 9:32 am

Well done.

When I’ve done similar things, I’ve used one of those ultra miniature Vigortronix AC to DC converters with success.

22nd Mar 2024, 4:21 pm	#1
Lef de art Pentode Join Date: Oct 2019 Location: Nicosia, Cyprus. Posts: 165	Bluetooth receiver to old cassette player Good evening guys. I want to install a bluetooth receiver on a 1970 tape recorder. The problem is that when I use the internal cassette player power supply on the Bluetooth receiver there is a Very loud hum in the speakers. The Bluetooth light turns on but the hum is that loud that i can hear nothing at all! It sounds like i connect dc voltage to the sound input!!! This does not happen when I use an external power source on bluetooth. However I would like to use the internal transformer of the cassette player and not add a second one. Does anyone know if I can do something to the bluetooth power supply with a circuit? Thanks in advance. I use the correct dc voltages in both cases (internal or external power supply)

22nd Mar 2024, 11:41 pm	#2
Lef de art Pentode Join Date: Oct 2019 Location: Nicosia, Cyprus. Posts: 165	Re: Bluetooth receiver to old cassette player And the problem is solved by using a B1212S-1W (isolated dc-dc converter 12v) . Hope my post will help other similar situations.

23rd Mar 2024, 9:32 am	#3
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,871	Re: Bluetooth receiver to old cassette player Well done. When I’ve done similar things, I’ve used one of those ultra miniature Vigortronix AC to DC converters with success.