I wish to make a small, USB-powered USB audio solution for use with headphones.
Is there something better I could use than say the PCM2706, while still being practical? (I hope so!)
I'm fine with making PCBs, working with SMD, etc. I'm not familiar with what chips would be best for this though-- what I would use for a home set up would sound great, but not be possible in a reasonable size or all from USB power. What is the best I can get that fits these constraints?
Is there something better I could use than say the PCM2706, while still being practical? (I hope so!)
I'm fine with making PCBs, working with SMD, etc. I'm not familiar with what chips would be best for this though-- what I would use for a home set up would sound great, but not be possible in a reasonable size or all from USB power. What is the best I can get that fits these constraints?
Do you mean a single chip solution like the PCM2706 that has a built in D/A and amp or
something like the PCM2706 that provides I2S out.
something like the PCM2706 that provides I2S out.
A one-chip solution like the PCM270x can offer would be great - but I have no problem with a multi-chip solution provided it works, and I'm assuming this is what is probably needed to get the best sound.
To get the "best" sound can depend on how much $ you want to spend.
PCM270x is a good starting point.
Adding a seperate D/A chip will improve the sound.
WM8524, AK4430 and ES9023 are pretty easy to implement.
There are much better USB receiver chips than the PCM270x but
they all suffer from NDA and having to deal with the manufacturer or
you need to be pretty handy with programming.
If you're after the best sound (and from what I'm reading it seems you are) then start with a TDA1387. I haven't found better sound at anywhere near the price. It takes I2S input so it'll need a USB adapter chip that puts out that. After the DAC you can use an AD815 which works at 5V quite nicely and it'll do I/V duty as well as power your headphones (it has minimum 400mA output current capability).
Adding a DC to DC converter to power an opamp with + and - might help. There are DIP and SIP modules that don't take up much space.
I vote for CM6631A. It's worth the extra effort, everything sounds more solidified, like you put jelly in a freezer.
For the headphone amplification stage you can consider ADA4627-1
For the headphone amplification stage you can consider ADA4627-1
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