Hello everyone, I'm glad to be here.
My name is Giannis and i am from Greece
I am a fan of electronics, and DIY constructions
I'm trying to build a simple volume controller that receives a balanced stereo signal (L&R XLR In),
for example from mixing console output,
control the volume with Digital pot,and go out to amplifier with balanced signal again (L&R XLR Out).
After research and effort, I have been able to control and use digital potentiometers.
I use the arduino to control potentiometers like AD8402, MCP4231, DS1803 etc
Αfter research I see that need a circuit of OpAmps to make it work but I do not know
which OpAmp & materials to choose and which schematic to follow.
If you can guide me and help me it will be a great pleasure.
I know that some or most of you will laugh about what I am asking because
it is simple for you but it is about to drive me crazy 🤣🤣🤣
Sorry for my English
Thank you very much in advance
My name is Giannis and i am from Greece
I am a fan of electronics, and DIY constructions
I'm trying to build a simple volume controller that receives a balanced stereo signal (L&R XLR In),
for example from mixing console output,
control the volume with Digital pot,and go out to amplifier with balanced signal again (L&R XLR Out).
After research and effort, I have been able to control and use digital potentiometers.
I use the arduino to control potentiometers like AD8402, MCP4231, DS1803 etc
Αfter research I see that need a circuit of OpAmps to make it work but I do not know
which OpAmp & materials to choose and which schematic to follow.
If you can guide me and help me it will be a great pleasure.
I know that some or most of you will laugh about what I am asking because
it is simple for you but it is about to drive me crazy 🤣🤣🤣
Sorry for my English
Thank you very much in advance
A simple passive scheme could work too:
I've ignored ground connection - with digipots you have to ensure the signals sit between the digipot's rails.
I've ignored ground connection - with digipots you have to ensure the signals sit between the digipot's rails.
thanks for the reply, i had tried this method and it works,
the only problem is when come a hot signal from console and the potentiometer works at full,
starts to make noises, cracks & pops.
especially when I tried with ground in place of the 5k resistor.
You'll need some coupling caps to get rid of the "wiper noise". It also depends whether your attenuator breaks before making contact with the next volume step.
Not with the right audio-friendly digital pots (typically make before break and some switch at zero-crossings only too).
can you suggest any of them? I have tried many but more or less they have the same effect.
I have already tried @10Κ the AD8402, DS1803, MCP4131 - 4231 - 4251 - 4261 - 42010 . @10Κ
For stereo differential potentiometer I recommend this: https://www.ti.com/product/PGA4311 Maximum input voltage is 2.5Vrms. If you need higher input voltage go to 2 x PGA2320 or 2 x PGA2310.
True, but they all still have some weirdness that comes through at lower frequencies. Note, its not close to as severe as with an RK27 alps pot, but its there enough to detract from the "refinement" expected from a top end piece of equipment. In balanced form, using one stereo attenuator for each channel, the noise becomes more "common mode" and dealt with the balanced topology.
The PGA2320 sounds best to my ears out of all them. The PGA2310 has more distortion and sounds a bit more scooped out in the mids.