REVIEW: HDPLEX 200W LPSU Linear Power Supply

For this review we took a closer look at the HDPlex 200W linear power supply. Asking price is 395$. A budget friendly lineair PSU, but is it worth the investment?

HDPLEX

HDPLEX is a company that specializes in fanless cases and power supplies for computer audio purposes. They are located in Hong Kong and this year they celebrate their 10 year existence. HDPLEX is famous amongst CAT users because the company offers decent quality at an affordable price.

What did you just say about your CAT? Well, it’s not a cute pet I’m talking about. CAT stands for Computer Audio Transport, a computer dedicated to audio only. An ideal way to play your digital files – high resolution PCM or DSD are recommended – and this computer is optimized in every aspect possible (hardware, software,….). If you build a decent CAT, and when using a decent external dac, for its price such setup is hard to beat when compared to current off-the-shelf alternatives.

Lineair power supply versus switching power supply

There are two main designs for the DC power supplies: Linear DC Power Supplies and Switching DC Power Supplies.

The traditional linear power supplies are typically heavy, durable, and have low noise across low and high frequencies. For this reason they are mostly suitable for lower power applications where the weight does not pose a problem. The switching power supplies are much lighter, more efficient, durable, and have limited high frequency noise due to the design. For this reason, the switching power supplies are not suitable for high frequency audio applications but are great for high power applications.

Linear DC power supplies were the mainstay of power conversion until the late 1970’s. With the advancement of switching power supply technology, linear power supplies are less popular today but still find themselves indispensable in applications that require very low ripple and noise. A linear power supply uses a big transformer to drop voltage from an AC line to much lower AC voltage, and then uses a series of rectifier circuitry and filtering processes to produce a very clean DC voltage.  That low DC voltage is then regulated into the desired voltage level by dropping the difference in voltage across a transistor or IC (the shunt regulator).

(Source: http://www.mastechpowersupplies.com/linear-power-supply-vs-switching-power-supply.html)

Setup used

 

I used the HDPLEX 200W lineair power supply on a new CAT (computer audio transport) I recently built myself and which consists of these components:

• Streacom FC9 Alpha case
• Intel i5 4570T
• Asus B85-MG motherboard
• PPA Studio OCXO clock on motherboard for input
• PPA Studio USB V3 card with OCXO clock for output
• PPA Studio 160W Pico PSU
• PPA Studio 2x 4Gb dual-channel 1.600 MHz DDR3 RAM
• 250 Gb Samsung 850 EVO SSD coupled to aluminium grounding block
• PPA Studio Red V3 SATA cable

Gebruikte software & OS optimalisatie:

• Windows Server 2016 standard GUI with Roon Server running as default shell
• Audiophile Optimizer 2.2 beta 5
• JPLAY 2.6 UltraStream mode
• Fidelizer Pro 7.9
• Project Lasso

I connected the HDPLEX 200W LPSU like this:

• 5V / 3A output connected to the PPA USB V3 card
• 12V / 10A output connected to the PPA 160W Pico PSU which powers the rest of the PC (SSD, motherboard/CPU, PPA OCXO clock for motherboard)
• XLR to DC jack power cables to connect the HDPLEX 200W LPSU to the PC are custom made by love cable
• Power cable to connect the HDPLEX to the mains is also love cable.

Other components:

• Mytek Brooklyn DAC with 100W HDPlex LPSU
• Lipinski L70 active reference monitors
• All cables by love cable
• Kemp elektronics Power Source
• Creaktiv Trend 4/4 hifi rack, all components coupled / decoupled with BlueStone plates & Creaktiv rubber dampers

HDPLEX 200W LPSU

Connections

The HDPlex 200W LPSU uses a “True Separate Ground Design”. There is no shared ground connection & no cross RFI/EMI interference on the different outputs used. The output rails are as follows:

• 19V via XLR
• 12V via XLR
• 5V via XLR
• 9V (user adjustable between 5V & 19.5V) via XLR
• 5V via usb type C

ELNA capacitors

The HDPlex 200W LPSU uses ELNA capacitors. These capacitors are widely used in high-end audio components for their sound characteristics. According to the manufacturer’s website they have a ripple Noise measurement of less than 3mv on the 19VDC/12VDC/9V/5V output.

 

Sound Quality

What I noticed immediately was the lower noise floor and the gain in tranquility. Upon using the 200W HDPlex lineair power supply I realized that music had been more restless prior to using this LPSU.

Anouar Brahem “Le Pas Du Chat Noir” (ECM, WAV 44 Khz/16 bit rip from original CD) is a beautifully recorded combination of Brahem’s Oud with piano & accordeon. Very emotional and atmospheric. A lush for the ear on a good installation. The addition of the HDPlex lineair power supply could let me hear deeper into the music. The piano was more focused, had more body, was perceived more “real”. The attack and decay of the Oud was beautifully rendered. The accordeon a treat for the mid woofers of my loudspeakers.

Babatunde Olatunji “Circle of Drums” (Chesky Records, DSD64 ripped from original SACD) is one of my references to test focus, control & impact of a system. Since these three characteristics were all improved with the HDPlex LPSU, the album was a treat to listen to. What also struck me, since noise floor got lower, I could hear more micro details in the different percussive elements the players use. Soundstage was wide, open & focused as never before. The rendition was tightly controlled & had fierce impact on my set of active Lipinski L70 monitors.

These monitors are active with a pure class A operation, no opamps in the signal path and a true reference amongst sound engineers (for instance Universal Mastering and Mobile Fidelity Sound Labs use Lipinski for their critical monitoring). But although they are a “reference”, they are only 2-way loudspeakers. It always surprises me that they actually perform full range, with a decent amount of impact, normally not expected from such small speakers. And when listening to Circle of Drums with the HDPlex in place,this surprise was even bigger.

2L is a label I discovered some years ago but has recently regained my interest, and I’m digging deeper into their recordings, exploring their catalogue. What interests me about this label is their philosophy: they try to recreate the live feeling (ambience, natural acoustics,…) by eliminating the studio environment (small room, closed-in walls thus unwanted reflections or unnatural perception of the performance). Instead 2L uses spacious acoustic venues (churches for instance) where they not only capture the performance but also the natural ambience and reverberations of the musician playing in this location, thus recreating the live feeling for the listener when reproducing the recording. These recordings are often made in DXD which is (in my opinion at least) about the summum of hires.

Piano improvisations by Ola Gjeilo (2L, WAV 192 Khz/24 bit downloaded from HDTracks.com) is such an example. Solo piano improvisations, recorded in the Sofienberg Church in Oslo, Norway. With the HDPlex in place, this recording really comes to live. I already liked the way my installation portraid the acoustic space but I am now even better able to differenciate every nuance in pianoplay, and the natural ambience of the church. A blissful experience to say the least.

 

HDPLEX 200W PSU & Mytek Brooklyn DAC

The improvements on my CAT were impressive. Would this also be the case when I would use another 200W PSU on my DAC? I contacted Larry at HDPLEX. Since I liked the improvement so much, so I decided to buy two units. One for my CAT & the other for my Mytek Brooklyn.

Immediately upon connecting the second HDPLEX to my DAC, the improvements were prominent. Again, more tranquility, more control, a quieter background (so more microdetails), more slam & impact. What also struck me was that the stereo image had grown. When this happens, sometimes the different instruments or voices can sound thinner. In this case the exact opposite had happened. Everything sounded bigger, with more detail, more lifelike, more real.

When listening to very good recordings of voices, like Diana Krall “Love Scenes” (DSD64, rip from original SACD) I could hear more details: I could hear her lips move with every word, her breathing after each sentence, even the saliva in her mouth passed by. A very lifelike & realistic experience!

The same happened with instruments. I recently bought the complete discography of young guitar genius Justin Johnson. On his album “Smoke & Mirrors” (WAV 16 bit / 44 KHz, ripped from original CD) he plays roots & blues on all kind of antique stringed instruments. The albums of Justin Johnson are mastered at Yes Master Studio in Nashville were they also use Lipinski monitoring (like I do) and recording quality is great. When he plays his strings they are displayed in such a realistic manner. I could hear every pluck, every vibration, the wood or metal guitar body, and so on. I was sitting in my sofa, listening with such amazement. I was shocked that this could be achieved with audio reproduction. One word: stunning.

 

HDPLEX 200W & router playing Tidal

Since I ordered two pieces from Larry at HDPLEX for my DAC & CAT, this left me with the review sample as a spare unit.

A couple of weeks later I got a visit from Frans, a Dutch audiophile who wanted to buy my old 100W HDPLEX. He would use the PSU to power his external cd-dvd-writer. He makes audio DVD’s for music playback. He claims that using the HDPLEX on the external writer brings a more silent background, more tranquility & more control into the music. The same findings I had when using the HDPLEX on my CAT & DAC. He also wanted to give me another tip: he told me that putting your router in the correct polarity would bring improvement when playing music via Tidal. Since I have star wiring around the house, I always have correct polarity. Nevertheless, all my components power plugs are connected in the same direction. I already knew that correct polarity can improve one’s system, but according to Frans, most people seem to forget this on their router.

So I did an experiment…

I hooked up the spare 200W HDPLEX to my router. I used a basic power cord and the basic XLR/DC minijack cord. The ethernet cable that connects the router with the CAT is decent: top of the line love cable. I don’t use wifi.

Normally I play music files from my SSD or from external HDD’s. I have a Tidal subscription but barely use it because Tidal is limited to flac 16/44 and I mainly listen to high resolution files.

I only listened music that I also have as audio files and that I had listened via Tidal prior to using the HDPLEX:

 

Conclusion

Everything just seems right, the music makes complete sence now. The HDPlex 200W linair PSU removed one of the last “weak links” in my CAT setup, enabling me to fully enjoy its potential, with complete focus on the music and the performance. Even my Tidal experience got improved when using this PSU on my router.

Of course there are even better power supplies on the market, or you could build your own. Another option would be using batteries to power your devices. People who don’t like such hassle, or people that just want a decent price / quality lineair power supply should look no further. HDPLEX will do the trick. Listening with these units was a real treat, and even more… simply stunning.

Where can I buy the HDPLEX 200W LPSU?

You can buy the HDPLEX 200W linear power supply via AudioPC.shop