Vacuum tube and tube-hybrid amplifiers, from single-ended Class A designs to Bluetooth integrated amps, with tube types, power and inputs.
Douk Audio F5 Single-Ended Class A Amplifier — read reviewA pure Class A single-ended tube power amp Douk Audio rates at 6W+6W, built on 6L6 and 6N1 tubes with tube-rolling sockets.
Nobsound DA3 Bluetooth Tube Amplifier — read reviewAn 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.
Nobsound DA7 Vacuum Tube Power Amplifier — read reviewA pure tube power amplifier with four 6P1 output tubes and three 6N1 driver tubes, rated 12W x 2 into 4 ohms, with Bluetooth 5.3, USB 3.0, dual RCA inputs and twin analog VU meters.
ST-01 PRO Bluetooth Tube Amplifier — read reviewA vacuum-tube hybrid amplifier with Bluetooth 5.0, USB DAC, and digital inputs, built for desktop hi-fi setups with passive bookshelf speakers.
Nobsound F2 Single-Ended Class A Tube Amplifier — read reviewA single-ended Class A tube amplifier delivering 9W x 2 into 8 ohm with 5U4G rectifier, 6SN7GT preamp and 6CA7 power tubes, all pluggable for tube rolling.
Douk Audio F3 Single-Ended Class A Amplifier — read reviewA single-ended Class A tube amplifier delivering 3.2W x 2 through GE 6DK6 driver and Valvo PL84 output tubes, with a real-time spectrum display and a handcrafted wood cabinet.
Douk Audio ST-02 Integrated Tube Amplifier — read reviewA 2.1-ready integrated amplifier combining a DAC, TPA3255 speaker amp, ECC83 tube stage and headphone amp in one chassis, with Bluetooth 5.4 and a dedicated subwoofer output. Listed as a pre-sale item.
Douk Audio T6PRO TPA3255 Tube Amplifier — read reviewHybrid stereo amplifier that pairs JAN5725 tubes with a TPA3255 Class D power stage for up to 300W per channel, adding Bluetooth 5.1, RCA and AUX inputs, a wide dual VU meter and a super-bass control.
Douk Audio X1 Bluetooth Tube Amplifier 160W — read reviewA $139.99 desktop tube amplifier with 160W + 160W of TDA7498E power, an MM phono input for turntables, aptX-HD Bluetooth and a subwoofer output for 2.1.
Nobsound AV-525 Bluetooth Vacuum Tube Amplifier — read reviewA hybrid tube and transistor amp Douk Audio rates at 100W+100W into 4 ohm, with Bluetooth, optical, coaxial and USB inputs.
All 10 tube amplifiers reviewed here come from one store, Douk Audio's store at doukaudio.com (six Douk Audio and four Nobsound), priced from $109.99 (the ST-01 PRO, listed as 'from') to $459.99 as priced on October 23, 2026. First work out where the tubes sit. Only four have tubes in the power stage that drives the speakers: the F2, F3 and F5 single-ended Class A amplifiers (a design whose output stage stays switched on) and the DA7. The other six are hybrids, with tubes in the preamp stage and transistors or a class D chip driving the speakers: the ST-01 PRO, ST-02, T6PRO, X1, AV-525 and DA3. The three Class A models are rated at 3.2W (F3), 6W (F5) and 9W (F2) per channel, and their reviews say they need efficient speakers; the F2 page recommends a sensitivity of 88dB or higher, meaning how loud the speaker plays for a given power.
Power figures need care. The ST-01 PRO is rated 100W+100W into 4 ohms, but its review reports that one independent reviewer measured about 30W per channel at 8 ohms. The AV-525's product page gives 100W+100W into 4 ohms and 70W+70W into 8 ohms, while the printed manual lists 200W+200W and a 64GB U-disk limit against the page's 128GB; the review used the product page and says to ask the store which applies to your unit. The F5's 6W+6W is Douk Audio's figure, and a forum thread estimated about 5.5W per channel. The T6PRO lists up to 300W per channel from its TPA3255 chip, a maximum that depends on the adapter and speakers; the DA3 lists 35W x 2 at 4 ohms and the DA7 12W x 2 at 4 ohms.
Check the mains voltage and the store's terms. The F5 lists AC 220V as the version shipped and marks its 110V version unavailable, so its review says buyers on 120V power should confirm with the store whether a step-up converter is needed; the DA7 lists AC 220V and the DA3 110V/220V, and both reviews say to confirm the version for your country. Douk Audio's store applies the same terms to every listing: shipping in 2-8 business days with duties, taxes and customs included in the checkout price unless noted (the ST-01 PRO review adds free shipping; none of the others gives a fee); returns requested within 30 days of delivery and approved by Douk first, shipped back within 7 days of approval, with original shipping fees and duties not refunded; and a 24-month warranty, although an older policy page still says 1 year.
Plan for handling and delivery. The ST-02 ($239.99) is a pre-sale listing, so expect a wait before dispatch; the AV-525's remote ships without batteries; and the T6PRO's base variants ship without a power adapter. The F3 must have speakers connected before it is switched on, because a missing load can damage its output transformer, and its tubes need 30-60 minutes to reach operating temperature. The DA7 has seven tubes and weighs 7.6kg, the F2 8.6kg. Only the DA3 lists a headphone jack, and the F5 takes two analog RCA sources only, with no digital input, phono stage or Bluetooth.
| Review | Price | Power | Tubes | Inputs |
|---|---|---|---|---|
| Douk Audio F5 Single-Ended Class A Amplifier | $459.99 | 6W+6W, pure Class A single-ended, into 4 or 8 ohm (Douk Audio's figure) | 6L6 x2 output + 6N1 x1 driver, pluggable for tube rolling | 2 groups of stereo RCA, per the page |
| Nobsound DA3 Bluetooth Tube Amplifier | $189.99 | 35W x 2 at 4 ohms / 25W x 2 at 8 ohms, 90W transformer | 2x 6J1 tubes in the preamp stage | Bluetooth, USB (U-disk up to 128GB), coaxial, optical, 2x stereo RCA |
| Nobsound DA7 Vacuum Tube Power Amplifier | $349.99 | 12W x 2 at 4 ohms and 8W x 2 at 8 ohms, 150W total consumption | 4x 6P1 power tubes plus 3x 6N1 for voltage amplification and driver stages | Bluetooth 5.3/5.0, USB 3.0, dual RCA in; banana speaker jacks and stereo RCA out |
| ST-01 PRO Bluetooth Tube Amplifier | From $109.99 | 100W + 100W into 4 ohm per the page; matches 3-8 ohm speakers | GE 4BZ6 per the page text, 6K4 per its description (count not given); TPA3250 power chip | Bluetooth 5.0, PC-USB, coaxial, optical, RCA, U-disk |
| Nobsound F2 Single-Ended Class A Tube Amplifier | $349.99 | 9W x 2 RMS at 8 ohm, ultralinear Class A operation | 5U4G rectifier, 6SN7GT preamp, 6CA7 power - all pluggable for rolling | 2 sets of stereo RCA with a front selector |
| Douk Audio F3 Single-Ended Class A Amplifier | $299.99 | 3.2W x 2 pure Class A, single-ended | GE 6DK6 drivers and Valvo PL84 output tubes | RCA line input for DACs, CD players and streamers |
| Douk Audio ST-02 Integrated Tube Amplifier | $239.99 | 300W x 2 max at 4 ohm; 107W+107W at 4 ohm with the 36V/6A adapter in the box | Custom ECC83, 180V high-voltage operation | Bluetooth 5.4, PC-USB, optical, coaxial, RCA, USB drives |
| Douk Audio T6PRO TPA3255 Tube Amplifier | $139.99 | Up to 300W per channel into 4-8 ohm speakers | JAN5725, run at 100V for true tube amplification | Bluetooth 5.1, 2x stereo RCA, 3.5mm AUX |
| Douk Audio X1 Bluetooth Tube Amplifier 160W | $139.99 | 32V/5A power supply included | JAN5725 in pluggable sockets for tube rolling | MM phono, Bluetooth 5.0 (QCC3034, aptX/aptX-HD), stereo RCA |
| Nobsound AV-525 Bluetooth Vacuum Tube Amplifier | $459.99 | 100W+100W into 4 ohm; 70W+70W into 8 ohm (Douk Audio's product-page figure) | EL84/6K4/5726 preamp tubes, WY2P rectifier; 4x Toshiba 5200 + 4x 1943 transistors (page text says 6A2/5726) | Bluetooth 5.0, USB U-disk, coaxial, optical, 2x stereo RCA |
It depends on what you want. The four with tube power stages are low in power (3.2W to 12W per channel) and suit efficient speakers. The hybrids add inputs such as Bluetooth, USB, optical and coaxial and more power from a solid-state stage, but the X1 review calls it tube-flavoured rather than a full tube power amp, and one independent reviewer found the ST-01 PRO's stock tone cooler than expected until EQ was adjusted. Decide on speakers, room size and inputs first.
Efficient ones. The F2 page recommends passive speakers rated 10-100W with sensitivity of 88dB or higher, at 4-8 ohms. The F2, F3, F5 and DA7 reviews say they need efficient speakers, and the ST-01 PRO review calls it a desktop or near-field amplifier for small to medium bookshelf speakers. The ST-02 and T6PRO list 4-8 ohm passive speakers.
Read them as the store's figures. The ST-01 PRO is rated 100W+100W into 4 ohms, but one independent reviewer measured about 30W per channel at 8 ohms. The AV-525 page says 100W+100W into 4 ohms while its manual says 200W+200W. The T6PRO's 300W per channel is a maximum that depends on the adapter and speakers. Ask the store which figures apply to the unit you will receive.
Check the version. The F5 lists AC 220V as shipped and its 110V version as unavailable, and its review says buyers on 120V mains should ask the store whether a step-up converter is required. The DA7 lists AC 220V and the DA3 110V/220V, and both reviews say to confirm the mains version for your country before ordering.
A tube rectifier is a tube that turns mains AC into the DC the circuit uses; the F2 has a 5U4G and the AV-525 a WY2P. Tube rolling means swapping tubes to change the sound. The F2's rectifier, 6SN7GT preamp and 6CA7 power tubes are all pluggable, as are the F5's 6L6 and 6N1 and the X1's JAN5725, but the listings name only certain replacements.
Douk Audio's store allows a return request within 30 days of delivery. Douk must approve it first, the item goes back within 7 days of approval, and original shipping fees and duties aren't refunded. The warranty is 24 months from purchase for manufacturing defects, with free repair or replacement, excluding accidental damage, unauthorized modification and misuse, although an older policy page still says 1 year.