Hi everybody,
I'm working on a headphone amplifier project and I want to use an Arduino Mega Pro to control a MUSES72320 volume control board. The arduino needs 7-9V and a maximum of 200 mA. Since I want to integrate the power supply into the headphone amplifier case, I don't want to use a switching power supply to avoid high frequency disturbances.
Do you have a suggestion or schematic for this application?
I'm thinking about three solutions right now:
1. A transformator in combination with MUR860 diodes.
2. A transformator in combination with LM2574N-ADJ
3. Something like this for 7-9V: Security Check
Will option 2 or 3 introduce high frequency noise just like a conventional laptop switching power supply?
Thanks
seyl3r
I'm working on a headphone amplifier project and I want to use an Arduino Mega Pro to control a MUSES72320 volume control board. The arduino needs 7-9V and a maximum of 200 mA. Since I want to integrate the power supply into the headphone amplifier case, I don't want to use a switching power supply to avoid high frequency disturbances.
Do you have a suggestion or schematic for this application?
I'm thinking about three solutions right now:
1. A transformator in combination with MUR860 diodes.
2. A transformator in combination with LM2574N-ADJ
3. Something like this for 7-9V: Security Check
Will option 2 or 3 introduce high frequency noise just like a conventional laptop switching power supply?
Thanks
seyl3r
Exactly what DC voltage is available inside the amplifier?
Is it capable of an additional 200mA load?
Is it capable of an additional 200mA load?
@duncan2: Thanks, LM7809 seems discontinued :-/
@ rayma: Nothing really, I have +-15V from a commercial power supply for the headphone amplifier and the MUSES, however, I don't want to use this for the digital section.
@ rayma: Nothing really, I have +-15V from a commercial power supply for the headphone amplifier and the MUSES, however, I don't want to use this for the digital section.
7809T: Fairchild Semiconductor : IC LM7809CT 9V 1A Positive Voltage Regulator : ICs & Semiconductors
Also: use LM7805 plus two resistors or a 3.9V Zener.
You can use a 7805 (or any other 5V regulator) to power the microcontroller from your +18V analog supply.
The trick is to put the microcontroller in deep sleep with the clock off. That way it generates absolutely zero noise because it is completely off. Then you use a pin change interrupt to wake it up when one of the outputs from the volume rotary encoder changes state. The micro wakes up, does its job, then after a timeout without the knob turned, goas back to sleep.
You don't need the whole arduino, just the micro itself. That way you don't get noise from the USB chip, that you can't put to sleep.
The trick is to put the microcontroller in deep sleep with the clock off. That way it generates absolutely zero noise because it is completely off. Then you use a pin change interrupt to wake it up when one of the outputs from the volume rotary encoder changes state. The micro wakes up, does its job, then after a timeout without the knob turned, goas back to sleep.
You don't need the whole arduino, just the micro itself. That way you don't get noise from the USB chip, that you can't put to sleep.
@PRR: Thanks, that's seems like a good solution.
@peufeu: Do you think the arduino will add a lot of noise? I mean every DAC out there has a USB controller and clocks and stuff? I could also put a housing around it.
@peufeu: Do you think the arduino will add a lot of noise? I mean every DAC out there has a USB controller and clocks and stuff? I could also put a housing around it.
Arduino has pretty bad layout, no ground plane.
If you use just the micro, put it on your board, add a ground plane, there will be less noise. Also it takes less space and it's simpler, one less board in your box, no wires, tidier, etc.
If you put the micro to sleep with clock off, that's zero noise, and you don't have to build an extra power supply, that's time and money lol.
If you use just the micro, put it on your board, add a ground plane, there will be less noise. Also it takes less space and it's simpler, one less board in your box, no wires, tidier, etc.
If you put the micro to sleep with clock off, that's zero noise, and you don't have to build an extra power supply, that's time and money lol.
Sounds reasonable, however, I have never worked with a controller itself - have to learn how to program it the way I want it to work. Also, i have no idea if I can use libraries I used in my sketch (which is already finished an working).
In total, I want to
- control the MUSES board
- an RGB LED
- read a rotary encoder+button
- read a 3 way switch
- switch three relays
In total, I want to
- control the MUSES board
- an RGB LED
- read a rotary encoder+button
- read a 3 way switch
- switch three relays
You don't have to learn how to program it... If you use an arduino with the micro on a DIP socket, you pull it out of the socket, put it on your board in a socket, and that's it 😉
The atmega328P on arduino is pre-programmed with a bootloader that allows you to program it via its serial port, so if you connect TXD RXG GND pins of the micro to where they were on the arduino, you'll be able to program it using the USB chip on the arduino just like before.
Note if you control a RGB LED via PWM this can create audible noise if the PWM frequency is in the audio range, because the LED current has to go somewhere, and it should not couple into the audio ground... But if you just control it on/off, then there is no noise.
The atmega328P on arduino is pre-programmed with a bootloader that allows you to program it via its serial port, so if you connect TXD RXG GND pins of the micro to where they were on the arduino, you'll be able to program it using the USB chip on the arduino just like before.
Note if you control a RGB LED via PWM this can create audible noise if the PWM frequency is in the audio range, because the LED current has to go somewhere, and it should not couple into the audio ground... But if you just control it on/off, then there is no noise.
Almost any Arduino can do what you need. Look at the new Nano series. They have a much smaller footprint then the Mega. I have them in three different components. No noise issues. I always mount them on a steal plate and keep them as far as possible from the audio section.
Well, I'm using a MEGA right now which doesn't have a socket. If I do the wiring by myself I could use the ATMEGA328P-PU which is part of the UNO.
I think I'll start with the Mega Pro and hand wiring first and once everything's working as I want it, I'll do a PCB without the Arduino and messy wires 🙂.
Thanks!
I think I'll start with the Mega Pro and hand wiring first and once everything's working as I want it, I'll do a PCB without the Arduino and messy wires 🙂.
Thanks!