Your DSD file is one thing; getting its bits to the DAC's converter is another. Over USB there are two transports: native DSD and DoP. The confusion to clear up first: both deliver the identical, unaltered DSD bits. The difference is purely in how they're packaged for the trip.
Native DSD
Native DSD sends the raw 1-bit stream to the DAC as DSD, with no wrapping. It's the most direct transport and supports the highest rates — but it isn't "class-compliant," so it generally needs a vendor-specific driver (on Windows, that usually means an ASIO driver). On platforms that don't allow such drivers, native DSD isn't available.
DoP (DSD over PCM)
DoP is a clever packaging trick. It takes the DSD bits and tucks them into the lower 16 bits of
ordinary 24-bit PCM frames, then stamps the top byte with a marker that alternates
between 0x05 and 0xFA on each frame. To the USB audio system it
looks like normal PCM, so it sails through the standard class-compliant driver
every modern OS already has. The DAC, seeing that telltale alternating marker, knows to unwrap the
frames and treat the contents as DSD.
The catch with DoP: rate and fragility
Because DoP carries DSD inside a PCM carrier, it needs a PCM rate high enough to fit. DSD64 rides in a 176.4 kHz/24-bit carrier; each higher DSD rate needs a proportionally higher carrier (DSD128 → 352.8 kHz, DSD256 → 705.6 kHz). At some point the carrier rate outruns what the USB link or DAC supports, which is where native DSD's headroom matters for the very high rates.
DoP's other property is fragility: since the markers live in the sample data, any volume change, resample, or DSP corrupts them, the DAC loses its DSD lock, and you get a blast of white noise. That's the whole reason DSD playback must be bit-exact.
Side by side
| Native DSD | DoP | |
|---|---|---|
| Packaging | Raw 1-bit stream | DSD wrapped in PCM frames |
| Driver | Vendor / ASIO needed | Class-compliant (built in) |
| Lossy? | No | No — bit-transparent |
| Top rate | Higher (DSD512+) | Limited by PCM carrier rate |
| Used on iOS? | No | Yes — the standard path |
Which one are you using?
On iOS and iPadOS, it's DoP — Apple's class-compliant USB audio has no native-DSD path, so DoP is how DSD reaches a USB DAC (see DSD on iPhone). On Windows with a vendor ASIO driver you may be on native DSD; on macOS and Linux it's typically DoP. Sound-quality-wise it doesn't matter: same bits, same music. Native only pulls ahead at the extreme rates DoP's carrier can't reach.
Whatever the chip does with those bits once they arrive is a separate story — inside your DAC. And if you're streaming from a computer, the 1-bit bridge just ships the file's bytes faster; the app still owns the DoP framing and the bit-exact path.