Douk Audio Tube Amplifiers Compared: Three Hybrids and Two Amps With Tubes in the Power Stage
Five Douk Audio and Nobsound tube amplifiers from $109.99 to $349.99: three hybrids and two with tubes in the power stage. Listed power is given at different loads, and the DA7 lists AC 220V only.
This page compares five tube amplifiers sold on doukaudio.com. Three are hybrids that put tubes ahead of a chip or solid-state power stage: the Douk Audio ST-01 PRO and X1 and the Nobsound DA3. Two have tubes in the power stage: the Nobsound F2 and DA7. They cost from $109.99 to $349.99, as priced on October 26, 2026. Douk Audio and Nobsound are two brand names sold by the same store, whose contact page says it is run by Shenzhen Anba Technology Co., Ltd (Shenzhen, China) and HONGKONG LONGSHENG Import and Export Trading Co., Limited (Hong Kong). We have reviewed ten tube amplifiers there; the other five are the F3 at $299.99, the F5 and AV-525 at $459.99 each, the T6PRO at $139.99 without a power adapter and the ST-02. Product figures are the store's own: we have not listened to or measured these amplifiers.
Three things decide what you are buying. First, where the tubes sit. Of the ten we reviewed, only the F2, F3, F5 and DA7 use them in the power stage, the part that drives the speakers; the other six put tubes in the front end ahead of a chip or transistor power stage. Second, how the power is labeled. The ST-01 PRO's 100W+100W and the X1's 160W+160W, both at 4 ohm, are labeled max output power, the X1's with its 32V/5A supply. The DA3's 35W x 2 and the DA7's 12W x 2, both at 4 ohm, are labeled rated, and the F2's 9W x 2 is RMS at 8 ohm. None of the five pages gives a distortion level at the rated power. Third, mains power. The DA7 page lists AC 220V only, while the F2 prints AC 110V-120V / 220V-240V and the DA3 AC 110V / 220V without saying which version ships.
Returns are the part of Douk Audio's terms to read twice. The current return and refund page, read on October 25, 2026, says to ask within 30 days of delivery, wait for approval and ship the item back within 7 days of approval. The item needs all its packaging and accessories and no excessive wear, or the store can refuse it or refund only part of the price. Original and expedited shipping, duties, taxes and customs charges are not refunded unless the law requires it or the store made the error, and the page does not say who pays return postage. An older refund page still online excludes mistaken orders and change-of-mind returns from free after-sale service and gives a 1-year warranty. The current warranty page says 24 months for manufacturing defects, with free repair, a replacement unit and free shipping both ways for covered repairs.
Shipping is quoted two ways. The current shipping page says orders are generally processed no later than the next business day and arrive in 2-8 business days, with duties, taxes and customs fees included in the checkout price unless noted. An older page still online says airmail takes 10-25 days for parcels under 2 kg, DHL, UPS or FedEx 5-8 days above that, and the store is not responsible for import duties. Prices can depend on the destination you pick: the DA7 is $349.99 for the US, UK and EU and $469.99 for AU and Other, and the X1's Other option is $148.99. Two product pages we did not pick carry notices of their own: on October 25, 2026 the F3's still read 'Orders Begin Shipping After July 20,2026.' and the ST-02's said shipping to all regions starts December 1.
At a glance
| Pick | Price | Tubes and power stage | Listed power | Inputs | Outputs, as listed | Supply at this price | Where to buy |
|---|---|---|---|---|---|---|---|
| Entry price with PC-USB, optical and coaxial inputsST-01 PRO Bluetooth Tube Amplifier | From $109.99 | GE 4BZ6 (text) or 6K4 (description); TPA3250 power chip | Max 100W+100W into 4 ohm; rating gives no supply or distortion level | Bluetooth 5.0, PC-USB, coaxial, optical, RCA, U-disk (64G) | Banana speaker jacks, 3.5mm AUX pre-out | 24V adapter in the box; DC 18-30V input | Check price at Douk Audio |
| Turntable (MM phono) input and a supply in the boxDouk Audio X1 Bluetooth Tube Amplifier 160W | $139.99 | JAN5725 x2 (JAN5654 elsewhere); TDA7498E class-D chip | Max 160W+160W into 4 ohm, with its 32V/5A supply | Bluetooth 5.0, stereo RCA, MM phono | Banana speaker jacks, subwoofer output | 32V/5A supply in the box; DC 19V-35V input | Check price at Douk Audio |
| Hybrid with a headphone jack and a pre-outNobsound DA3 Bluetooth Tube Amplifier | $189.99 | 2x 6J1 preamp tubes; solid-state power stage | Rated 35W x 2 at 4 ohm; 25W x 2 at 8 ohm | Bluetooth (no version given), 2 RCA, coaxial, optical, U-disk (128G) | Banana jacks, stereo RCA pre-out, 3.5mm headphone | AC 110V / 220V IN; no power cord on packing list | Check price at Douk Audio |
| Single-ended Class A with swappable tubesNobsound F2 Single-Ended Class A Tube Amplifier | $349.99 | 5U4G rectifier, 6SN7GT preamp, 6CA7 power; Class A | 9W x 2 RMS at 8 ohm, ultralinear; no 4 ohm figure | 2 sets of stereo RCA with a front selector | Banana speaker jacks | AC 110V-120V / 220V-240V; power cable in the box | Check price at Douk Audio |
| Tubes in the power stage, plus Bluetooth and USBNobsound DA7 Vacuum Tube Power Amplifier | $349.99 | 4x 6P1 power tubes, 3x 6N1 driver tubes | Rated 12W x 2 at 4 ohm; 8W x 2 at 8 ohm; no distortion level | Bluetooth 5.3/5.0, dual RCA, USB (U-disk to 128GB) | Banana speaker jacks, stereo RCA | AC 220V IN only; power cord in the box | Check price at Douk Audio |
1. Entry price with PC-USB, optical and coaxial inputs
ST-01 PRO Bluetooth Tube Amplifier
The cheapest and smallest of the five (115 x 98 x 54mm): a hybrid listed from $109.99, the same for every shipping destination, with a 24V adapter, a remote without batteries, a USB cable and an antenna in the box. Its table lists a max output power of 100W+100W into 4 ohm, with no distortion level or supply voltage given for that rating. The page names the tube GE 4BZ6 in its text and 6K4 in its description, with no count, and gives USB as 96KHz/24Bit in the parameters but up to 32-bit/768kHz in the features.
- Best for
- Desktop or near-field listeners with small passive bookshelf speakers who want Bluetooth and digital inputs with a tube-hybrid look.
- Skip if
- Anyone needing to drive larger, less-efficient speakers at real volume, or expecting a classic warm tube sound straight out of the box.
2. Turntable (MM phono) input and a supply in the box
Douk Audio X1 Bluetooth Tube Amplifier 160W
$139.99 includes the 32V/5A supply and, per the packing list, two JAN5725 tubes, though a feature heading and a later paragraph say JAN5654 and the page does not say which pair ships. A TDA7498E class-D chip is listed at a maximum of 160W+160W into 4 ohm, with THD of 0.5% and SNR above 90dB and no test conditions. It is the only pick whose page lists a phono input (MM), and it has a subwoofer output; no headphone output is listed. The store's data also lists a crossed-out price well above $139.99, which nothing shows was ever charged.
- Best for
- Turntable owners who want one desktop amp covering vinyl, Bluetooth and a 2.1 subwoofer setup.
- Skip if
- You use a moving-coil cartridge, or you want a genuine tube power stage or a headphone output.
3. Hybrid with a headphone jack and a pre-out
Nobsound DA3 Bluetooth Tube Amplifier
$189.99 buys two Beijing 6J1 tubes in the preamp stage ahead of solid-state power, rated 35W x 2 at 4 ohm and 25W x 2 at 8 ohm, with THD of 1% and SNR of 70dB and no test conditions. It is the only pick whose page lists a headphone output (3.5mm, with no power or impedance range given), and it has a stereo RCA pre-out for active subwoofers. The packing list shows only the amplifier and a Bluetooth antenna, with no power cord or remote, and the page prints AC 110V / 220V IN without saying which version ships.
- 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
4. Single-ended Class A with swappable tubes
Nobsound F2 Single-Ended Class A Tube Amplifier
$349.99 buys an 8.60kg single-ended Class A amplifier with a 5U4G rectifier, a 6SN7GT preamp tube and 6CA7 power tubes, all pluggable, with replacements named for each. It lists 9W x 2 RMS at 8 ohm in ultralinear operation and THD under 1% at 1kHz, but no figure at 4 ohm and no distortion level at the rated power; it recommends speakers rated 10-100W at 88dB or higher. The packing list names the amplifier, a power cable and a manual, with no separate line for the tubes, and the page prints AC 110V-120V / 220V-240V without saying which version ships to the US.
- Best for
- Listeners with efficient passive speakers who want real single-ended Class A tube sound and the freedom to roll all three tube types.
- Skip if
- Your speakers are inefficient or power-hungry, you need digital or phono inputs onboard, or shelf space is tight for an 8.6kg amp.
5. Tubes in the power stage, plus Bluetooth and USB
Nobsound DA7 Vacuum Tube Power Amplifier
$349.99 is the price for US, UK and EU destinations; the store's options price AU and Other at $469.99. It uses four 6P1 power tubes and three 6N1 driver tubes and is rated 12W x 2 at 4 ohm and 8W x 2 at 8 ohm, with THD of 1% at 1kHz and no distortion level at the ratings. Against the F2 at that price, it adds Bluetooth 5.3/5.0, USB with U-disk playback to 128GB and twin analog VU meters, but names no replacement tubes. The page lists AC 220V IN only; its packing list names the amplifier, a power cord and an antenna, with no separate line for the tubes.
- Best for
- Listeners who want genuine tube amplification with modern inputs — Bluetooth, USB files and RCA — paired with efficient speakers in a small or medium room
- Skip if
- Your speakers are low-efficiency or the room is large, or you are on 110-120V mains and cannot confirm the correct voltage version
How we compared
We compared these amplifiers from the store's product pages, as summarized in our full review of each, and from Douk Audio's current and older shipping, return and refund pages, its 24-month warranty page and its contact page, all read on October 25, 2026. We have not listened to or measured these amplifiers: 'listed' on this page means printed on the store's page, and every power, tube, input and size figure is the store's own.
Where a listing or the store's own pages disagree or leave a gap, this page says so. The main cases: the ST-01 PRO's tube (GE 4BZ6 in the page text, 6K4 in the description, no count) and its USB resolution (96KHz/24Bit against up to 32-bit/768kHz); the X1's tube (JAN5725 in the packing list, JAN5654 named in a heading); the T6PRO's and ST-02's 300W x 2 headlines, which no supply in their own tables reaches; the F5's 110V version, listed as unavailable; the F3's July shipping notice; the store's shipping page (2-8 business days, duties included) against its older one (airmail 10-25 days, duties not covered); and its 24-month warranty page against the older refund page's 1 year. The picks are labeled by need, not ranked against each other; each price comes from the pick's review and was last checked on the date shown beside it.
Each pick links to its full review and the sources behind it. How we research
Questions before you buy
Are Douk Audio tube amplifiers real tube amplifiers?
It depends on the model. Of the ten we reviewed, four use tubes in the power stage: the F2 (6CA7), F3 (PL84), F5 (6L6) and DA7 (6P1). The other six pair tubes with a solid-state power stage: a TPA3250, TPA3255 or TDA7498E chip on the ST-01 PRO, T6PRO, ST-02 and X1, Toshiba transistors on the AV-525 and a solid-state stage on the DA3. Several pages name their tubes two ways, so check the tube listed on the product page.
How much power do Douk Audio tube amplifiers put out?
The DA7 lists a rated 12W x 2 at 4 ohm and 8W x 2 at 8 ohm, the DA3 a rated 35W x 2 at 4 ohm and 25W x 2 at 8 ohm, and the F2 9W x 2 RMS at 8 ohm, while the ST-01 PRO and X1 list a max output power of 100W+100W and 160W+160W at 4 ohm. The T6PRO and ST-02 headline 300W x 2, yet no supply in their own tables reaches it; the T6PRO's 32V/5A row gives 78W+78W. All are listed figures with different labels and no distortion level at the rating, so they are not like for like.
Do Douk Audio tube amplifiers run on 120V US power?
Check each page. The DA7 lists AC 220V only, and the F5 lists 220V as the version currently available, with 110V unavailable. The F2 prints AC 110V-120V / 220V-240V and the DA3 AC 110V / 220V, and neither says which version ships; the F3 lists AC 100-240V and the AV-525 gives no input voltage. The ST-01 PRO, X1 and ST-02 list a DC adapter in the box, the X1's with no plug type given; the T6PRO's $139.99 option has none. Ask [email protected] in writing before you order.
Which Douk Audio tube amplifier has a phono input or a headphone output?
Of the ten we reviewed, only the X1 lists a phono input. It is listed as MM, and the X1's page does not say whether a moving-coil cartridge works. Only the DA3 (3.5mm) and the ST-02 list a headphone output. The X1, T6PRO and AV-525 reviews say their pages list none; the F2, F3, F5, DA7 and ST-01 PRO pages list banana speaker jacks, plus a stereo RCA output on the DA7 and a 3.5mm AUX pre-out on the ST-01 PRO.
What is Douk Audio's return policy for its amplifiers?
The current return and refund page says to ask within 30 days of delivery, wait for approval and ship the item back within 7 days of approval. Items need all packaging and accessories and no excessive wear, or the store can refuse them or refund part of the price. Original and expedited shipping, duties, taxes and customs charges are not refunded unless the law requires it or the store made the error, and the page does not say who pays return postage. The older refund page excludes mistaken orders and change-of-mind returns.
How long does Douk Audio shipping take, and are duties included?
The current shipping page says orders are generally processed no later than the next business day and arrive in 2-8 business days, with duties, taxes and customs fees included in the checkout price unless noted. An older shipping page still online says airmail takes 10-25 days for parcels under 2 kg, DHL, UPS or FedEx 5-8 days above that, and the store is not responsible for import duties. Check the delivery estimate and any duties at checkout.