Feature One Amp for All Your Sources: One reason ST-01-PRO has stayed relevant over the years is simple: it keeps your favorite sources ready in one system. Bluetooth 5.0, PC-USB, optical, coaxial and RCA keep phones, TVs, computers and players connected without swapping cables, while USB drive playback adds direct support for lossless WAV, FLAC and APE. Confident Power for Home HiFi: Brings serious drive to your stereo system. Its TPA3250 delivers up to 100W × 2 at 4Ω for 3–8Ω passive speakers, while the included 24V power supply is ready to drive most home speakers with ease. Add a powered subwoofer through the pre-out for an easy 2.1 upgrade, or connect active speakers or another amp as your system grows. Warm Character with Personal Tuning: Voiced around carefully selected GE 4BZ6 tubes for satisfying sound from the start, it brings a smoother character to vocals and instruments, while the warm tube glow adds unmistakable classic HiFi appeal. Bass and treble controls offer ±6 dB adjustment, making it easy to fine-tune the balance for your speakers, room and music. Watch Your Music Come Alive: The custom VU meter gives every track a visible pulse, while AGC automatically adapts to changing signal levels, keeping the needle expressive from quiet passages to dynamic peaks. Framed by warm tube glow, gold accents and an aluminum chassis, ST-01-PRO becomes as captivating to watch as it is to hear. Stay in Control from Your Seat: Switch inputs, adjust volume, mute, and manage Bluetooth or USB playback from the remote, while clear front-panel indicators show exactly which source is active. Clear Bluetooth pairing for easier reconnection, and toggle the 10-second no-signal auto-mute to keep idle moments quiet. Parameters Brand: Douk Audio Model: ST-01-PRO Audio Inputs: Bluetooth 5.0 / PC-USB / Coaxial / Optical / RCA / USB Drive Audio Outputs: Speaker Output (Banana Jacks) / 3.5 mm Pre-Out Maximum Output Power: 100 W × 2 @ 4 Ω Speaker Impedance: 3–8 Ω Amplifier Chip: TPA3250 Supported Sampling Rates: PC-USB: Up to 96 kHz / 24-bit Bluetooth: Up to 48 kHz / 24-bit Coaxial / Optical: Up to 192 kHz / 24-bit USB Drive Audio Formats: MP3 / WAV / WMA / FLAC / APE Maximum USB Drive Capacity: 64 GB USB Drive File System: FAT32 Bass / Treble Adjustment: ±6 dB Supported PC-USB Systems: Windows XP / 7 / 8 / 10 / 11, macOS, Linux Frequency Response: 20 Hz–20 kHz (±1 dB) SNR: ≥98 dB THD: 0.07% Power Input: DC 18–30 V Included Power Adapter: 24 V DC Dimensions (W × D × H): 115 × 98 × 54 mm / 4.53 × 3.86 × 2.13 in Net Weight: 671 g / 1.48 lb Package Dimensions (W × D × H): 295 × 225 × 85 mm / 11.61 × 8.56 × 3.35 in Package Weight: 1.4 kg / 3.09 lb Packing List 1 × ST-01 PRO Amplifier 2 × Vacuum Tubes 1 × 24V DC Power Adapter (ONLY provided when selecting the power option at purchase) 1 × Remote Control (2 × AAA batteries not included) 1 × Bluetooth Antenna 1 × Optical Cable 1 × USB Cable 1 × User Manual FAQ Q: Why is there no sound from the optical or coaxial input? A: Make sure the optical or coaxial port on your source device is an output, not an input. When connecting a TV, set the digital audio format to PCM and select a supported sampling rate. Q: Why is there no music after inserting a USB drive? A: Switch ST-01-PRO to BT/USB mode and make sure the USB drive is FAT32 formatted and no larger than 64 GB. Supported formats include MP3, WAV, WMA, FLAC and APE. Q: Can I connect a phone through the PC-USB input? A: Yes. It supports OTG and includes an OTG-compatible USB cable for direct connection to compatible USB-C phones and tablets. For iPhones or iPads with a Lightning port, a high-current camera adapter is required. Q: Why does the input indicator go out while adjusting volume? A: This is normal. At minimum volume, the BT/USB indicator flashes; at maximum, the PC-USB indicator flashes. The current input indicator temporarily turns off and returns once adjustment stops. Q: Do volume, bass and treble adjustments affect both outputs? A: Yes. Q: Can the vacuum tubes be replaced? A: Yes. ST-01 PRO uses 4BZ6 tubes and should only be replaced with the same model. The supplied tube model may vary by production batch; please refer to the actual product received. Q: Are batteries included for the remote control? A: No. The remote control requires 2 × AAA batteries, which are not included.

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