Douk Audio D2 15W Linear Power Supply Review
A 15W linear power supply with sub-20uV ripple, one DC and one USB-A 5V output, and a sealed transformer plus LM1085IT regulator for noise-sensitive 5V audio devices.
Our verdict
The D2 is an $89.99 linear power supply for 5V desktop gear: DACs, DDCs, Raspberry Pi boards, USB audio devices and small headphone amps that are held back by noisy switching adapters. It quotes under 20uV of ripple, uses a sealed transformer with an LM1085IT regulator and Panasonic FM capacitors, and offers one DC and one USB-A output at up to 15W total. It is fixed at 5V and the two outputs share the 2.5A budget - and Douk Audio warns ground noise can appear if you power two devices at once.
- Best for
- Owners of 5V desktop audio gear - DACs, DDCs, Raspberry Pi streamers - who want to swap switching adapters for a low-ripple linear supply.
- Skip if
- Your device needs anything other than 5V, you plan to run two hungry devices at full rated current, or you need adjustable output voltage.
Why 3.6/5: Lifted by a stated 5V, 2.5A rating, plug size, input voltages, size, weights and a cable set in the box. Held back by ripple figures that differ on the page (20uV and 23uV), a 15W rating that 5V at 2.5A does not reach and sound claims with no measurements.
The Douk Audio D2 is a 15W linear power supply priced at $89.99. It replaces ordinary switching power adapters with clean, stable 5V DC power, helping reduce power-related noise and interference for a darker background, smoother highs and more natural detail in a compact HiFi system.
The headline number is ripple noise below 20uV under no-load conditions, with 15W output power and up to 2.5A current - a low-noise foundation for sensitive audio circuits. Inside, a custom sealed transformer feeds an LM1085IT voltage regulator with Panasonic FM capacitors and a PTC resettable fuse, a combination chosen for steady 5V output, low-ripple DC power and added circuit protection.
The D2 provides two outputs: one USB-A and one DC jack, so it can power two compatible 5V devices at the same time - typical targets are DACs, DDCs, Raspberry Pi boards, USB audio devices and headphone amps. Two limits are worth knowing: the total current drawn from both outputs must not exceed the 2.5A rating, and Douk Audio notes ground noise can occur with some device combinations when powering two at once, in which case they recommend powering only one device. The DC jack is 5.5mm/2.5mm and works with 5.5mm/2.1mm plugs, and the output is fixed at 5V with only about +/-0.5V of fine adjustment available. The CNC-machined aluminum chassis is compact and stack-friendly with better heat dissipation than a plastic brick.
Specifications
| Spec | Page says |
|---|---|
| Brand | Douk Audio |
| Model | D2 |
| Output Interface | DC / USB Port |
| Output Voltage | DC 5V |
| Output Power | 15W |
| Rated Output Current | 2.5A |
| Ripple Noise | No load <23μV |
| DC Output Connector | 5.5 × 2.5 mm, positive inside and negative outside, compatible with 5.5 × 2.1 mm |
| Input Voltage | AC 110V–120V / AC 220V–240V |
| Dimensions (W × D × H) | 125 × 80 × 40 mm / 4.92 × 3.15 × 1.57 in |
| Net Weight | 600 g / 1.32 lb |
| Package Weight | 900 g / 1.98 lb |
| Packing list | 1* D2, 1* DC Cable, 1* Power Cable |
| Ripple (feature text) | below 20μV under no-load conditions |
| Outputs (feature text) | 1×USB-A and 1×DC; the total current of both must stay within the rating |
How it compares
The D2 is the 5V member of the group's linear supplies. The Douk Audio D2-PRO 35W Linear Power Supply with Dual DC 12V Outputs review ($129.99, $40.00 more, for its US option) has a fixed 12V output on two DC jacks with a 2.5A maximum and a sealed toroidal transformer, in a larger 115 x 161 x 62mm, 1.33kg case. Its page gives ripple as 28uV RMS (no load), against 'below 20uV' in the D2's feature text and '<23uV' in its Parameters; neither page states the measurement method. Both list the same 5.5 x 2.5mm plug (compatible with 5.5 x 2.1mm) and a 2.5A rating, so the real choice is the voltage your device needs, 5V or 12V.
The Douk Audio DC Power Supply Adapter review ($24.99, $65.00 less) is a different kind of product: regulated adapters for amplifiers whose options start at 19V, so none fits a 5V device, and its page gives no ripple figure. Choose the D2 for a 5V DAC, streamer, Raspberry Pi or USB audio device, the D2-PRO for 12V gear, and the adapter family only for a Douk Audio or Nobsound amplifier that needs 19V to 48V.
Shipping, returns and warranty
- Shipping: Douk Audio's 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 otherwise.
- Older shipping terms are still online: airmail at 10-25 days for parcels under 2 kg, DHL, UPS or FedEx at 5-8 days above that, and a line saying the store is not responsible for import duties. Check the delivery estimate and any duties at checkout.
- Returns: ask within 30 days of delivery and wait for approval before sending anything; an approved return has to ship within 7 days. Items need all packaging and accessories and no excessive wear, or the store can refuse them or refund part of the price. Refunds go to the original payment method after inspection.
- Not refunded: original and expedited shipping, duties, taxes and customs charges, unless the law requires it or the store made the error. The return page does not say who pays return postage, and the older refund page excludes mistaken orders and change-of-mind returns from free after-sale service.
- Warranty: 24 months from purchase for manufacturing defects, with free repair, a replacement unit and free shipping both ways for covered repairs. Drops, liquid, DIY repairs, lightning, extreme temperatures and misuse are excluded (partial fees may apply), and damage from weak packing on the way back may not be covered. The older refund page still says 1 year.
- Seller: the site is run by Shenzhen Anba Technology Co., Ltd (Shenzhen, China) and HONGKONG LONGSHENG Import and Export Trading Co., Limited (Hong Kong); support is by email at [email protected]. These terms cover orders placed on doukaudio.com; other sellers apply their own.
For this product, the page offers 'Shipping from' choices of US, UK, EU, AU and China and shows Free Shipping, 2-8 Days Arrival, 30-Day Return and 2-Year Warranty badges near the price.
What we liked
- Ripple below 20uV under no load gives 5V audio circuits a clean, stable foundation versus switching adapters
- Dual outputs - one DC jack and one USB-A - can power two compatible 5V devices at once
- Quality parts include a custom sealed transformer, LM1085IT voltage regulator, Panasonic FM capacitors and a PTC resettable fuse
- Compact CNC-machined aluminum chassis is stack-friendly and improves heat dissipation
- Aimed at exactly the devices that benefit most: DACs, DDCs, Raspberry Pi and USB audio gear
Worth noting
- Output voltage is fixed at 5V with only about +/-0.5V of fine-tuning, so it suits 5V devices only
- The two outputs share the rated current - total draw must stay within the 2.5A rating rather than 2.5A each
- Douk Audio notes ground noise can appear when powering two devices at once, and recommends using the D2 with a single device if that happens
Questions before you buy
Can both D2 outputs be used simultaneously at full rated current?
No. You can connect two output devices at the same time, but the total current drawn from both outputs must not exceed the rated output current.
Is the output voltage adjustable?
The output voltage is essentially fixed at 5V and can only be fine-tuned within about +/-0.5V; normally no adjustment is required.
Will ground noise occur if I power two devices at once?
It depends on the connected devices. If ground noise occurs when powering two devices, Douk Audio recommends using the D2 to power only one device.
My device needs 5V / 1A - is the D2's 2.5A output safe to use?
Yes. 2.5A is the maximum available current, and your device will only draw the current it needs, so it can be used safely.
Sources & verification
What this review is based on and the day we last read it. Specs and claims from the maker are the maker’s own; the verdict and the rating are ours.
From the store
- Douk Audio product pagePrice $89.99 for every ships-from option, features, parameters (5V, 15W, 2.5A, ripple, plug, input, size, weights), packing list and FAQs.Read October 25, 2026
- Douk Audio shipping policyOrders are generally processed no later than the next business day, 2-8 business days in transit, duties, taxes and customs fees included at checkout unless notedRead October 25, 2026
- Douk Audio older shipping policyOlder terms still online: airmail 10-25 days under 2 kg, DHL/UPS/FedEx 5-8 days above, store not responsible for import dutiesRead October 25, 2026
- Douk Audio return and refund policy30 days from delivery with prior approval, ship back within 7 days; shipping, duties and taxes not refunded unless the store erredRead October 25, 2026
- Douk Audio older refund policyOlder terms still online: 30-day free return or refund and a 1-year warranty; mistaken orders and change of mind are excludedRead October 25, 2026
- Douk Audio 24-month warranty page24 months from purchase for manufacturing defects: free repair, replacement unit and two-way shipping for covered repairs; lists exclusionsRead October 25, 2026
- Douk Audio contact pageSite run by Shenzhen Anba Technology Co., Ltd and HONGKONG LONGSHENG Import and Export Trading Co., Limited; support emailRead October 25, 2026
What we couldn’t verify
- Ripple: the review's 'below 20uV' comes from the feature text, while the page's Parameters list 'No load <23uV'; the store's own product description gives that Parameters line as '<20uV', so its two texts disagree. The Ripple row shows both figures; neither has a stated bandwidth or method.
- The page lists 15W output power, but 5V at its rated 2.5A comes to 12.5W; it does not say what the 15W refers to.
- The input is listed as 'AC 110V-120V / AC 220V-240V' with no mention of a voltage switch or separate regional versions; the 'Shipping from' options (US, UK, EU, AU, China) all cost the same.
- 'Darker background, smoother highs, more natural detail' and 'ultra-high PSRR' are page claims; the page gives no PSRR figure, load regulation or independent noise measurement.
- The FAQ says the D2 runs warmer than a switching supply and that ground noise can appear when two devices share it; it gives no temperature or ground-isolation figure.
Spotted an error or something out of date? Tell us and we’ll fix it and update the date.
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