Powering a preamp directly from the power amp rails is an issue as power amp rails are not clean but carry distorted version of the amplified signal and mains ripple.
Ground routing is important, ground loops can pickup hum. You have loops from power block to power amp to preamp because you power the preamp direct from the block, rather
than daisy-chaining it from the power amp (yes two power amps makes this problematical).
If you power the preamp unit separately and connect the screen for each audio interconnect you should have a loop-free system.
Ground routing is important, ground loops can pickup hum. You have loops from power block to power amp to preamp because you power the preamp direct from the block, rather
than daisy-chaining it from the power amp (yes two power amps makes this problematical).
If you power the preamp unit separately and connect the screen for each audio interconnect you should have a loop-free system.
Might wanna read the TPA3118 topic here for solutions, easiest and fastest fix is lowering the gain: Cheap TPA3118D2 boards, modding them and everything that comes with it
That bt module might be noisy too, you could try a dc-dc isolator in power rail. Best bt module I've used, had that isolator on board, good quality and noise free.
That bt module might be noisy too, you could try a dc-dc isolator in power rail. Best bt module I've used, had that isolator on board, good quality and noise free.
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