BTR AMP
DSD (Direct Stream Digital) is the 1-bit, ultra-high-sample-rate format behind SACD, developed by Sony and Philips. The waveform is encoded as pulse density, with noise shaping delivering roughly 120 dB of audible-band dynamic range. Downloads usually come as .dsf or .dff files:
| Rate | Sample frequency | ≈ PCM resolution |
|---|---|---|
| DSD64 | 2.8224 MHz | 24-bit/88.2 kHz |
| DSD128 | 5.6448 MHz | 24-bit/176.4 kHz |
| DSD256 | 11.2896 MHz | 24-bit/352.8 kHz |
Why iPhone can't play DSD natively
iOS has no DSD support — the built-in Music app cannot open a .dsf or .dff file, and no iPhone hardware plays a 1-bit stream directly. Every DSD setup on iOS therefore runs through a player app, which either packs the untouched bitstream into PCM frames for an external DAC (DoP) or converts it to PCM in real time. The DSD guide explains both paths and how to choose a DAC.
How BTR AMP plays DSD
BTR AMP plays DSD from DSD64 up to DSD256 — the maximum achievable on iOS. Connect a USB DAC that supports DoP and the original DSD bitstream is delivered bit-perfect, nothing resampled or converted. On any other output — wired headphones, Bluetooth, AirPlay, car audio — DSD converts to high-resolution 352.8 kHz PCM on the fly, and output behavior is tunable per device in settings.
DoP packs the raw DSD bits into PCM carrier frames — 176.4 kHz for DSD64, 352.8 kHz for DSD128, 705.6 kHz for DSD256 — so a DAC’s maximum PCM input rate is also its maximum DoP rate. The DSD guide covers the mechanics and what to check on a spec sheet.
DSD tracks sit in the same library as FLAC, ALAC, and every other supported format, with the exact codec shown on every track. DSD playback shipped in version 22.0 and is a Pro feature.
Getting your DSD files onto your iPhone
DSD albums are large — several gigabytes at DSD256 — so a fast local transfer pays off.
Send files over Wi-Fi from any browser on your computer (Connect → Wi-Fi Transfer), pull them from Google Drive, OneDrive, iCloud Drive, an SMB share, or WebDAV, use AirDrop, or play straight from a USB drive. The transfer guide walks through each method, and the importing guide covers the details.