I've been looking at Bluetooth modules for my projects. Modules like this Sure Electronics AA-AB41136 Bluetooth 4.0 Audio Receiver Board aptX +EDR 12 VDC sure are tempting. They're cheap and look like they're real easy to use. But I've read a lot about ground loop problems with these types of boards. It seems like the go to solution is to use audio coupling transformers, which I am not going to do.
I realize that a board like this probably doesn't isolate clean and dirty grounds. Combined with haphazard installation this could certainly create a ground loop problem, I would think.
Using a separate transformer winding to power the board is an obvious solution, but not usually practical. I presently have this Dayton Audio BTR01 Bluetooth Audio Receiver with 24-bit/48 kHz Optical Coaxial RCA Outputs which provides adequate service with no ground loop problem, but it's powered by a wall wart. As a DIYer, I obviously want to integrate the Bluetooth function into my preamp.
So I'm asking you to please share any experience or advice you have on this topic. Personally, I suspect that if I install it with my usual methods then I won't have the problem. I suspect that many people on the Web just don't know how to correctly wire audio circuits for low noise and distortion.
Thank you.
I realize that a board like this probably doesn't isolate clean and dirty grounds. Combined with haphazard installation this could certainly create a ground loop problem, I would think.
Using a separate transformer winding to power the board is an obvious solution, but not usually practical. I presently have this Dayton Audio BTR01 Bluetooth Audio Receiver with 24-bit/48 kHz Optical Coaxial RCA Outputs which provides adequate service with no ground loop problem, but it's powered by a wall wart. As a DIYer, I obviously want to integrate the Bluetooth function into my preamp.
So I'm asking you to please share any experience or advice you have on this topic. Personally, I suspect that if I install it with my usual methods then I won't have the problem. I suspect that many people on the Web just don't know how to correctly wire audio circuits for low noise and distortion.
Thank you.
Of course. The key word is isolated.
Many boards containing both Bluetooth and amplifiers are available. The site I linked to has a whole bunch of them. I'm not convinced that the engineers that designed these boards used drastic measures like a DC-DC converter to isolate the Bluetooth. It has to be how they wire the grounds. This is the trick that I must know.
I'll probably get one and experiment with it. I suspect that you can maybe isolate the grounds on the board by removing a jumper or cutting a trace.
I don't see why an audio device wouldn't have separate clean and dirty grounds. I often build my boards that way if called for. I understand that it could be confusing for some people.
Many boards containing both Bluetooth and amplifiers are available. The site I linked to has a whole bunch of them. I'm not convinced that the engineers that designed these boards used drastic measures like a DC-DC converter to isolate the Bluetooth. It has to be how they wire the grounds. This is the trick that I must know.
I'll probably get one and experiment with it. I suspect that you can maybe isolate the grounds on the board by removing a jumper or cutting a trace.
I don't see why an audio device wouldn't have separate clean and dirty grounds. I often build my boards that way if called for. I understand that it could be confusing for some people.
I've seen app notes for bluetooth chips where they recommend a small choke in series with the power line, and I expect this is to help suppress the high frequency switching noise which ends up affecting the audio when it returns through the ground connection. But a small isolated power supply works well, something like the B0505.
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