Price: $685 (Quad Rail)

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Formed in 2007, HDPLEX Ltd. had and still has this single mission of producing high quality fan-less computer cases with minimalist design features.

Two of our prototype products, the H5.S and the H10.ODD, gained immediate recognition once they were released into the consumer market.

During the design process of our signature fan-less chassis, we found it rather hard to locate small, silent, and fan-less power supplies on the market, which gradually became a huge obstacle in creating truly versatile fan-less computer case. This turned out to be a turning point in our expansion strategy: we listened and took our customers’ feedback into consideration, and eventually we stepped into the realm of fan-less, highly efficient, silent power supply. It is now known as our NanoATX series.

The NanoATX Power Supply is an internal AC-DC adapter + DC-ATX converter combination, which is fully ATX compliant. Such combination is compact, fan-less yet rather powerful, replacing bulky and loud ATX/SFX power supply for small form factor PC. Our NanoATX Power Supply has enjoyed tremendous popularity in many SFF PC projects, such as the NFC S4.

Our first attempt is the 120W AC-DC and 160W DC-ATX combo, released in 2013.

With the NanoATX combo in place, our classic H1 fan-less PC case was introduced in 2014, to replace its chunkier predecessor, the H3 series. H1 remains the smallest ITX PC case which fully supports internal power supply solution and does not rely on external AC adapter. The H1 series also provide optional back plate for Thin-ITX motherboard.

Year 2016 saw the birth of our direct-plug 160W DC-ATX, replacing two prior models: the none-direct-plug 160W DC-ATX and 300W AC-DC with PFC adapter. The 160W DC-ATX immediately became a market leader, as it is the only direct-plug DC-ATX converter which supports PCIExpress rail and modular output. Our NanoATX product line now offers two fully passive internal power supply solutions for customers with such demands.

Our company has made a long journey and we never stop the pursuit for excellence. To commemorate our core value as well as the 10th anniversary of our company, we will soon present the 2nd Gen H1/H1.SODD and HDPLEX Cube. We look forward to a new chapter in the next 10 years.

Build & Specifications

  • Twelve Linear Technology LT3045 chips for two adjustable rails to achieve extremely low noise.
  • Hi-End Audio ELNA Super 10000µf Capacitor, One for Each Rail, Eliminating Phase Distortion
  • High Quality 300W Silent R-Core Transformer provides clean energy
  • High Precision Over-Current Protection and Over Temperature Protection Achieved by LM2904+MCU Control
  • Separated Ground for Each Output Rail
  • EMI/RFI Circuit to Prevent AC Grid Pollution
  • No Humming or Buzz noise for 50Hz and Peak load, 100% Silent
  • High Quality Neutrik XLR Connector for All Outputs
  • Low ripple noise and void of high frequency noise
  • 19V/10A XLR Output Supprt Thin ITX/NUC/Auralic Aries Mini/HDPLEX 4000W DC-ATX Converter
  • 12V/10A XLR Output Support Legacy Wavelet DAC/Qnap Nas/PicoPSU or 12V based CE device.
  • Two independent adjustable output is 3.3V/5V/7.5V/9V/12V/15V and 3AMP MAX. Each rail uses six LT3045 chips. It supports SoTM PCIE USB card/MicroRendu/Upton USB Regen/ PPA (Paul Professional Audio) USB Audio card and Squeezebox.
  • Passive aluminum chassis guarantee absolute silent and stable operation


The HDPLEX is very popular among HTPC and audiophiles alike. And for good reason. You get great sound, four outputs (two adjustable), and a single enclosure. For that reason alone, I feel like it’s worth the price of admission. The 300W kind of sits between the budget and high-end gear – but remains very flexible. For what it’s worth, I own two of these supplies and don’t plan on selling them.

The Sound

The HDPLEX 300W is one of the more organic sounding power supplies on this list. It is all about tonal intent and musicality. However, it does skip over some of the technicalities and special effects that some audiophiles enjoy. You won’t ever feel like “they’re in the room,” but it’s a raw sound with good resolution and imaging.

Brass sounds particularly descriptive with the HDPLEX 300W. Horns have riveting textures and the spatial information is transmitted wonderfully. I would say this power supply sounds more romantic than it is dark. There are clear details but it isn’t too clean. Although there is a slight edginess in the upper mids, the HDPLEX is surprisingly quiet. The blanket of warmth is overlayed in heightened sound space. This is great for appreciating reverbs and resonances in live recordings.


The biggest problem with the HDPLEX 300W is the flatter layering compared to the higher-end offerings. Everything is closer together and overlayed on top of each other. At times, the music will sound congested and clumsy. It’s not pancake flat (thank goodness), but it’s getting there.

The lack of acoustic molding is very obvious. Everything sounds more 2D and not well outlined. As such, imaging is more smeared and not very focused. It doesn’t expand or layer out the soundstage well and there just isn’t a lot of spatial clarity. Textures are a little soft and the presentation isn’t meaty enough to “feel” the music. In other words, not a very tangible sound.

Unfortunately, the bass won’t crack the floor open. In fact, it’s a bit on the lighter side in comparison to some of the other power supplies. It’s tight and textured but doesn’t protrude. That said, it does have decent slam and attack. Bass guitars and cellos don’t have that grunt and thickness to the sound – but it’s still believable.

Who Should Buy the HDPLEX 300W?

Well for one, if you need four rails, it’s tough to beat the form factor, performance, and price of the HDPLEX 300W. The effective cost is only $170 per rail!

The HDPLEX represents a middle ground where you get tonal satisfaction, sufficient detail, enough upper-frequency life, and unscathed dynamic expression. Aside from tone, it doesn’t particularly excel at anything but takes it all in stride. It’s like going to a restaurant with a B health rating. It’ll have a few violations but the food is better than some pedantic A-rated places. So for the money, I find it really hard to be too critical.



  • Ostensibly natural, warmish natural tone

  • Quiet background

  • Good resolution

  • Overall great tonal balance

  • Best value at $170 per rail

  • Imaging isn't the greatest

  • A bit of grain and roughness. So not the most smoothest or connective.

  • Not a full-bodied sound

  • Soundstage isn't very deep

  • Not very tangible.


vs. Sean Jacobs DC4

  • The DC4 has a much larger and meater sound.
  • The DC4 has a slightly wider soundstage
  • The HDPlex has more air and shine
  • The DC4 is in another league when talking about texture, body, and overall dimensionality.
  • DC4 sounds more real in every way, but the tonality of the HDPlex is more natural.
  • DC4 has more control and gravity…and quite a bit more bass

vs. JCAT Optimo 3 Duo

  • Optimo 3 Duo has much better layering and separation.
  • HDPLEX has more texture
  • Optimo 3 Duo has far better molding.
  • Tone is true for both in different ways. The Optimo is darker, the HDPLEX is warmer…but perfection is in the middle.
  • Optimo is smoother and quieter.

vs. Paul Hynes SR4-12

  • HDPLEX is more vivid and airy
  • HDPLEX’s tone is a little more grey-brown in comparison to the SR4-12
  • SR4-12 has heftier bass but it’s tighter on the HDPLEX.
  • The SR4-12 is smoother and more shaped out
  • HDPLEX has better resolution and has a blacker background
  • SR4-12 has much more natural tone.
  • The HDPLEX is speedier and more light-footed. But it’s rougher and leaner.
  • HDPLEX has more obvious outlines.

vs. Fidelizer Nikola2

  • The Nikola2 is meatier and more dynamic.
  • The Nikola2 is the better power supply but slightly pricier for a single rail (instead of 4)