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Nobsound DA3 HiFi Bluetooth Tube Amplifier with Coaxial, Optical and USB Inputs Review

An integrated tube amplifier rated 35W x 2 at 4 ohms, with two 6J1 tubes in the preamp stage, Bluetooth, USB, coaxial, optical and dual RCA inputs, plus a headphone output and a pre-out for subwoofers.

3.83.8 out of 5 starsUpdated October 14, 2026
$189.99Price checked October 14, 2026
Check price at Douk Audio
Nobsound DA3 HiFi Bluetooth Tube Amplifier with Coaxial, Optical and USB Inputs

Our verdict

The Nobsound DA3 is a flexible tube-hybrid integrated amp for $189.99, rated 35W x 2 into 4 ohms with two 6J1 tubes up front and just about every input a modern listener needs — Bluetooth, USB file playback, coaxial, optical and dual RCA. Tone controls, a headphone jack and a subwoofer pre-out add everyday convenience. Its 1% THD and 70dB SNR signal a warm, colored sound; confirm the 110V/220V mains version for your region.

Best for
A one-box tube-hybrid desk or shelf system feeding passive speakers, with digital, wireless and vinyl-era sources all able to connect
Skip if
You want ruler-flat measured performance or deep bass extension below 60Hz, or you need confirmed 120V operation before ordering
Check price at Douk AudioHow we research

The Nobsound DA3 is an integrated tube amplifier priced at $189.99. It combines a tube preamp stage with solid-state power amplification: two Beijing 6J1 tubes shape the signal ahead of an output stage rated at 35W x 2 into 4 ohms and 25W x 2 into 8 ohms, driving speakers through banana jacks.

Connectivity is the DA3's strongest suit. Alongside standard RCA inputs and speaker outputs it offers Bluetooth, USB lossless playback from a U-disk (up to 128GB, supporting FLAC, APE, MP2, MP3, WMA, AAC, MP4, M4A and WAV), optical and coaxial digital inputs, a PRE OUT for active subwoofers and a 3.5mm headphone output. Dual RCA inputs make it easy to connect and compare two sources, and a dedicated input switch with indicator light keeps operation simple.

The tube design is credited with a rich, smooth and warm character and a subtle harmonic richness that makes vocals sound natural and detailed. Independent treble and bass adjustments let you tailor the balance by genre. The power supply is built around a 90W transformer and four 2200uF 35V electrolytic capacitors for clean, stable delivery, in a chassis measuring 170x259x147mm and weighing about 3kg.

The published specifications are honest about the design's priorities: frequency response of 60Hz-20kHz (±3dB), SNR of 70dB, THD of 1% and RCA input sensitivity of 500mV. That profile suits listeners chasing tube warmth rather than ruler-flat neutrality. Note also that the spec sheet lists AC 110V/220V input, so check which mains version you are ordering for your country.

Shipping is worldwide with free and expedited options, and cost varies by country. At 3kg net, this amplifier ships via DHL, UPS or FedEx in an estimated 5-8 days rather than by airmail. Import duties and customs fees are the customer's responsibility. Free 30-day returns with a full refund and a 1-year warranty apply to all items, excluding orders placed by mistake, man-made damage or misuse, subjective change of mind, and anything else outside the warranty terms.

What we liked

  • Tube-hybrid integrated design: two 6J1 tubes in the preamp stage add harmonic richness and warmth to vocals
  • Unusually broad inputs for the price — Bluetooth, USB playback from a U-disk, coaxial, optical and two RCA pairs
  • U-disk playback supports FLAC, APE, MP3, WMA, AAC, MP4, M4A and WAV files up to 128GB
  • Independent treble and bass controls, a headphone output and a pre-out for active subwoofers cover more use cases than a plain power amp
  • Beefy power section with a 90W transformer and four 2200uF capacitors, plus an input indicator light and dedicated input switch for easy switching

Worth noting

  • The published specs are modest — THD of 1% and SNR of 70dB — so this is a warm, characterful amp rather than a measurements-first one
  • The spec sheet lists AC 110V / 220V input, so confirm the mains-voltage version for your country before ordering
  • The frequency response is quoted as 60Hz-20kHz (±3dB), which limits deep bass extension compared with wider-bandwidth designs

Questions before you buy

What can I connect to the DA3?

Bluetooth devices, a USB U-disk with audio files, coaxial and optical digital sources, and two stereo RCA inputs. Outputs include banana speaker jacks, a stereo RCA PRE OUT for active subwoofers and a 3.5mm headphone jack.

What file formats does USB playback support?

U-disk playback supports FLAC, APE, MP2, MP3, WMA, AAC, MP4, M4A and WAV, with a maximum storage of 128GB.

What is the output power?

35W x 2 at 4 ohms or 25W x 2 at 8 ohms, from a design using two 6J1 tubes, a 90W transformer and four 2200uF 35V capacitors.

What are the shipping and warranty terms?

Worldwide shipping with free and expedited options; at around 3kg this amp ships by DHL/UPS/FedEx in about 5-8 days. Import duties are the customer's responsibility. Free 30-day returns for a full refund and a 1-year warranty apply, excluding orders by mistake, misuse, change of mind and anything outside the warranty terms.

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