For my car audio system I need ground loop isolators. The signal then goes to a passive audio mixer and balanced audio (double isolated RCA cables still had alternator whine). I don't want to spend the necessary money on decent isolators with transformers, and I hear the whole idea is bad anyway.
I've bought IL300 analog optocouplers and drew the sample circuit from the datasheet. Only difference is how the ground reference needs to be vcc/2 since teh audio signal is AC and not DC. I'm not sure if I properly set up the power supplies. Is this correct? Do I need a simple rail splitter for VCC/2 instead of a resistor divider?
Datasheet
www.vishay.com/docs/83622/il300.pdf
I've bought IL300 analog optocouplers and drew the sample circuit from the datasheet. Only difference is how the ground reference needs to be vcc/2 since teh audio signal is AC and not DC. I'm not sure if I properly set up the power supplies. Is this correct? Do I need a simple rail splitter for VCC/2 instead of a resistor divider?
Datasheet
www.vishay.com/docs/83622/il300.pdf
An externally hosted image should be here but it was not working when we last tested it.
No need for the circuit. You can use capacitors in both the connections, i.e. signal and ground.
Gajanan Phadte
Gajanan Phadte
Your biasing is wrong, you should use 0V as signal ground and capacitively couple Vcc/2 to the op-amp inputs. Look up battery or single supply powered op-amp circuits for some ideas.
Do not do this! That has the potential to spoil your audio and will make no difference to the problem.
I have looked into this issue before and found that simply adding a little PCB with balanced outputs close to the head unit solved the alternator whine problem. Obviously my boot mounted crossover had balanced inputs.
Keep us informed as I have been looking at this chip as an alternative to transformers myself. I went with transformers in the end though as I felt the chip had inherent limitations for audio signals.
Do not do this! That has the potential to spoil your audio and will make no difference to the problem.
I have looked into this issue before and found that simply adding a little PCB with balanced outputs close to the head unit solved the alternator whine problem. Obviously my boot mounted crossover had balanced inputs.
Keep us informed as I have been looking at this chip as an alternative to transformers myself. I went with transformers in the end though as I felt the chip had inherent limitations for audio signals.
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What size/type of cap would you suggest? Would a different value be used in the common connection?
It is already suggested to one poster earlier and it works. Think it to be like a transformer.
Gajanan Phadte
Gajanan Phadte
It is nothing like a transformers action.
If you consider the frequency of what you want to pass and what you want to filter, you can see it will never work.
If you consider the frequency of what you want to pass and what you want to filter, you can see it will never work.
hmm I can't decode all of that
now I'm using a TLE2426 to set up a proper virtual ground like with the CMOY circuits I've used a lot
Virtual Ground Circuits
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