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 Post subject: Bluetooth Passive Amplifier
PostPosted: Mar Mon 05, 2018 1:19 pm 
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Joined: Feb Mon 27, 2017 4:53 am
Posts: 60
Location: Chicago
I have a number of working Grundig stereo consoles and was just building a few bluetooth connectors so that I can connect my phone via bluetooth and play music through the old stereo. I've been following this schematic with good success:


I have a Grundig KS 752 ( that works perfectly with the above passive amplifier. This stereo is a solid state version.

I created two more passive amps for other non-solid state stereos (, but the sound sounds as if the gain is turned all the way up. There's some distortion, but the sound level is good. I suspect that I need to add a resistor to each channel on the output side.

Any guidance on if resistors are need and what value or what the problem might be?

 Post subject: Re: Bluetooth Passive Amplifier
PostPosted: Mar Wed 07, 2018 3:41 am 
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Joined: Dec Sat 24, 2011 9:17 pm
Posts: 3158
Location: Vancouver Island, Canada
Could try this other circuit.

Watch the doughnut, not the hole.
Burl Ives, RIP, oldtimer.

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