Hi All ,
I have just brought an Ak4493 Bluetooth module and am using it off the same 12v SLA 7amp battery as my chip amp TDA7377 (no noise when connected by 3.5mm to phone) and big surprise there’s now a bit of ground loop. Just wondering wether using 2 separate dc filters such as these may help .
Thanks in advance Simon https://www.aliexpress.com/item/100...param-url=scene:search|query_from:#nav-review
I have just brought an Ak4493 Bluetooth module and am using it off the same 12v SLA 7amp battery as my chip amp TDA7377 (no noise when connected by 3.5mm to phone) and big surprise there’s now a bit of ground loop. Just wondering wether using 2 separate dc filters such as these may help .
Thanks in advance Simon https://www.aliexpress.com/item/100...param-url=scene:search|query_from:#nav-review
You might try a hum-buster circuit to help isolate grounds:
Another thing you can do is reduce loop area of the ground loop. The bigger the loop, the more of an antenna it is.
That said, may I ask how you know the problem is due to a ground loop? Also, is there something in particular about the sound that suggests a ground loop as being the problem?
Another thing you can do is reduce loop area of the ground loop. The bigger the loop, the more of an antenna it is.
That said, may I ask how you know the problem is due to a ground loop? Also, is there something in particular about the sound that suggests a ground loop as being the problem?
Hi. Possible solution is isolated dc/dc converter, it will break ground loop. No filters will help in this case, as power ground from amplifier shares its input ground. Same apply to bluetooth module - same signal and power ground.
Or use separate power supply sources for bluetooth and amplifier, like separate batteries. Bigger one for amplifier,smaller for bluetooth.
Or use separate power supply sources for bluetooth and amplifier, like separate batteries. Bigger one for amplifier,smaller for bluetooth.
Agree that a test with two batteries might be useful to help with figuring out what's going on. Doesn't necessarily have to be a ground loop if all the circuitry is floating, although it could be.
There could also be issues with RF from the bluetooth module getting into the amp chip, or maybe something is oscillating when its all hooked together, etc.
There could also be issues with RF from the bluetooth module getting into the amp chip, or maybe something is oscillating when its all hooked together, etc.
Thanks All for the responses ,
I watched a YouTube video on types of background noise and it would seem to be “GPU noise” sort of static with rhythmic crackling ☺️and not a ground loop .
I brought a separate battery for the DAC but 6v Sla due to space (which should be within spec of the DAC) and this completely eliminated the noise and improved the sound quality . However the Bluetooth connection only worked when the battery was fresh off the charger so the DACs 5v to 20v spec is clearly off .
I ended up back with both on the main 12v battery using one of the AliExpress 20A Dc filters for the amp which almost completely cut the noise out ,could only hear with my ear to the speaker .
I may well try another one of these filters on the DAC or possibly find a very Compact 12V battery.
I watched a YouTube video on types of background noise and it would seem to be “GPU noise” sort of static with rhythmic crackling ☺️and not a ground loop .
I brought a separate battery for the DAC but 6v Sla due to space (which should be within spec of the DAC) and this completely eliminated the noise and improved the sound quality . However the Bluetooth connection only worked when the battery was fresh off the charger so the DACs 5v to 20v spec is clearly off .
I ended up back with both on the main 12v battery using one of the AliExpress 20A Dc filters for the amp which almost completely cut the noise out ,could only hear with my ear to the speaker .
I may well try another one of these filters on the DAC or possibly find a very Compact 12V battery.