Hi
I have a 15VDC Switching power supply source I need to bring down to 5VDC to power a bluetooth receiver.
So far I tried a small Switch Buck converter and I get the EEEE switch frequency sound.
Is there a schematic to give a pure 5VDC supply without any background noise?
Thanks
I have a 15VDC Switching power supply source I need to bring down to 5VDC to power a bluetooth receiver.
So far I tried a small Switch Buck converter and I get the EEEE switch frequency sound.
Is there a schematic to give a pure 5VDC supply without any background noise?
Thanks
ok let me look into that.
thanks
thanks
Yes it definitely it,, so how do I clean it out? thanks.
If the current draw on the SMPS is under 3 amps, Mark Johnson's PO89ZB filter may clean it up. See: https://www.diyaudio.com/community/...all-warts-preamps-hpa-korg-nutube-etc.354213/
A kit with PCB and parts is sold in the DIYAudio store for little money, but I think they are currently sold out.
A kit with PCB and parts is sold in the DIYAudio store for little money, but I think they are currently sold out.
Try with brand new aa batteries... 1.65V each... 3 in series will give you a clean 5V DC. If that works, ditch the SMPS.... just avoid plugging them into the mains outlets full stop.
P = U x I. So (15 - 5) x I. With only 50 mA this will be 0.5W of energy wasted to heat. Also the regulator will need to filter out the garbage which is not its strongpoint when it are very high frequency signals.
You would do a good choice by having a mini 6..7V transformer, rectifier, filter cap and LDO. Clean power, clean designing. Certainly if the 15V is not needed at all.
You would do a good choice by having a mini 6..7V transformer, rectifier, filter cap and LDO. Clean power, clean designing. Certainly if the 15V is not needed at all.
Here in India, a 0-12 or 12-0-12 linear power supply is tapped to feed a 7805, for the FM / Bluetooth modules, and a capacitor to ground (small ceramic) is used as noise filter on both sides of the regulator.
A 7.5 to 12 V linear (transformer) based supply will work, you have still to figure out how to reduce noise from the SMPS, provided you still need it.
Those wall warts based on transformers are about $1.50 here, 7805 is also cheap.
For 50 mA, that is enough.
Add a small heat sink for safety's sake to the 7805.
Whacko left field solution is to use an old cell phone charger, try it...5V clean, see if it is noisy on the sound side.
Old Nokia chargers work very well, many are discarded for damaged pins, easy fix, one less for the landfill. Those are the old button phone chargers, many lying around the house unused as higher rated ones are needed for smart phones, and the pins are different.
A 7.5 to 12 V linear (transformer) based supply will work, you have still to figure out how to reduce noise from the SMPS, provided you still need it.
Those wall warts based on transformers are about $1.50 here, 7805 is also cheap.
For 50 mA, that is enough.
Add a small heat sink for safety's sake to the 7805.
Whacko left field solution is to use an old cell phone charger, try it...5V clean, see if it is noisy on the sound side.
Old Nokia chargers work very well, many are discarded for damaged pins, easy fix, one less for the landfill. Those are the old button phone chargers, many lying around the house unused as higher rated ones are needed for smart phones, and the pins are different.
