Thursday, January 6, 2022

Audiophile DC Power Supplies Supertest


In a simple world, switched-mode power supplies should end up in the bin. Linear power supplies rule because that is what everyone says. Let's have a look at whether there is any wisdom in conventional audiophile thinking?

The power supplies on test will be divided into two groups. The first group will be used to power  a Melco N100 Digital Music Library, which accepts a 12V power supply. The second group will be used to power a Weiss INT204 USB/SPDIF bridge that accepts a 6-9V power supply. 

Identical power cords will be used in all cases - an Oyaide Black Mamba. The power supplies will also be switched on one hour before any critical listening is done. Three tracks were played, To whom I give my heart by 2V1G, Colleen's dream by Pat Coil, and Chitlins Con Carne by Kenny Burrell.

12V Power Supplies 

Asian Power Devices DA-48T12 - FOC

This is the laptop brick power supply that is bundled with the Melco N100. It is rated for 4A of current. Unlike all of the other power supplies on test here, the AC inlet is a figure of eight type instead of an IEC inlet. A suitable converter was used to ensure that the same power cord could be used here. This turned out to be an important factor. Using an aftermarket figure of eight power cord (a more modest model compared to the Oyaide Black Mamba) killed the sonics of the Asian Power Devices brick. 

The sonics from the stock power supply was passable at their best. Bass lines while smooth and rounded, lacked depth and power. Vocals while warm and pleasant, were also lacking in clarity and definition. The two vocalists in the 2V1G track as an example, could not be clearly distinguished in the soundstage. The better power supplies in comparison clearly placed one singer in the center, and the other, a few feet away on the left. High frequencies were also lacking in crispness, extension and were a bit dull sounding.

Jay's Audio LPS25VA - USD 168

This is a super-regulated design derived from Walt Jung's super-regulator circuit. High-quality parts are used like a 25VA Talema mains transformer, Phillips BC reservoir caps, and Panasonic FC decoupling caps. This is a surprise given the modest price tag of the LPS25VA.

A front LED panel shows the output voltage, and a trimmer pot on the rear permits fine adjustments to the output voltage.

Somehow this power supply failed to float my boat. There was nothing particularly offensive about the sonics, but nothing to write home about either. While this is a more "quiet" sounding power supply compared to the Asian Power Devices and Meanwell bricks, there is a lack of attack and extension on both the low and high frequencies.   

Kingrex PSU Mk II - USD 419

An oldie but goodie. The Kingrex used to be a popular recommendation, but newer products on the market are more sophisticated from a technical point of view. Nevertheless, this model is still worthy of consideration. Featuring a 48VA toroidal transformer and a massive power supply, the Kingrex can be picked up at an affordable price on the pre-owned market.

Looking under the hood, this looks like a simple electronic design, with a three-pin regulator, and a variable resistor to set the output voltage.

I used my personally constructed DC lead for this, a Neotech PCOCC copper cable. The original lead was long lost in my hi-fi jungle.

Listening to the Kingrex brought back good memories. A competent performer in all departments, the Kingrex has good bass, and sparkling extended highs. Cymbals in particular, are reproduced with a crisp strike and decay. The midrange is warm and smooth, but some fine detail is lost. While the bass has weight, it lacked the tightness and slam managed by the best of the power supplies here. 

Pat Coil's piano playing and the saxophonist on Chitlins Con Carne lacked some impact and attack as an example.      

Kingrex SLAP - USD 450

Creative naming from Kingrex's marketing department! The SLAP is a Sealed Lead-Acid Battery Power supply unit. Weighing a whopping 7 kg, this brick is fuss-free with a built-in battery management circuit. Some people think that battery power is the only way to be truly isolated from the nasties on the electricity grid.

Meanwell GST60A12-P1J - USD 18

Meanwell is one of the big names in industrial and commercial power supplies. The model on test here is a 12V/5A brick switched-mode power supply. The Meanwell provided massive bang-for-the-buck. Users of the Melco that are on a tight budget could consider this as a no-brainer upgrade. You get better bass authority and control, clearer and more distinct vocals, and more extended highs. The Meanwell will not pose a threat to any of the better power supplies here, but you can't argue with its value proposition. 

Paul Hynes SR4-12 - GBP 342

The SR4 comes in two models, the SR4-12 which has user-selectable voltage settings from 5 to 12V, and the SR4-19 which has voltage settings from 9-19V.

The SR4 utilises a balanced mains isolation transformer and a discrete regulator circuit. Current output is 2A continuous and 20A for transients. The SR4-12 was tested with a silver wire DC lead that may be purchased from Paul Hynes as an option. 

I enjoyed listening to the SR4-12, although I felt that the sonics were shaped by the silver wire DC lead to a large extent. Quiet and confident-sounding, the Paul Hynes has lovely silky highs that are extended, yet delicate and refined. Authority and control are behind that of the Plixir Elite, and busy mixes did get a little bit messy at times.

If your musical diet consists of small-scale classical and jazz pieces, or female vocals, the SR4-12 will really suit you. 

Plixir Elite BDC 6A - S$ 1,059.30

Proudly made in Singapore, the Elite BDC features a balanced power transformer and three-stage noise regulation. This is the usual power supply used with the Melco. The Plixir has a firm and neutral sound, with good control over transients. This is a highly resolving power supply and a reference standard for me.

Sean Jacobs DC4 - from GBP 5,400 (no typo!)

The DC4 is the power supply that people talk about in hushed tones amongst those in the know. Entry to this hallowed circle requires very deep pockets and one additional rack - this power supply is as big as an amplifier.

The model I had on hand is able of supplying three 12V supplies, so that brings down the cost of ownership somewhat. Current is limited to 2A per rail due to "CX" module fitted in the regulator module, although this can be bypassed for higher current delivery. The stiff asking price buys you premium parts such as a custom-made toroidal transformer, Neotech OCC internal wiring, Vishay Z-foil naked resistors and Audionote Kaisei capacitors in critical sections.

Using a silver wire DC cable from Sean Jacobs, this power supply blew away most of the competition. While this is not the most forceful, incisive or dynamic sounding power supply, the DC4 was able to serve up extremely high amounts of detail while sounding natural and textured. The DC4 nailed timing, sounding just right. It has a level of refinement and quietness that exceeds even the Plixir Elite. However the Plixir has better slam and bass punch, and dishes up a very close level of performance for a lot less money. Like most statement-fi products, whether the price tag is justified depends on personal opinion.

Sbooster BOTW Power & Precision Eco - GBP 260

The Sbooster supports up to 3A of current and has selectable voltage between 12-13.2V. The Sbooster utilises a dual-stage mains filter and Earth line choke. The unit on test is the original model, which has since been replaced by a MkII version.

This is definitely a good step-up from stock power supplies, with a very quiet background and an increase in resolution and control. Bass has less authority than the Plixir and there is subtle grain and splash in vocals and transients. The midrange is also forward, which results in soundstage that is projected forward. 

SOtM sPS-500 - USD 500

Unlike its competitors, the sPS-500 is a switched-mode power supply. It has user-selectable voltages ranging from 7-19V and is capable of supplying up to 5A of current at 12V and 3.3A at 19V. The DC output socket uses a Hirose connector that will test your soldering skills if you intend to construct your own DC cable. As the supplied cable is annoyingly short, you will likely need to order an aftermarket cable.

This sPS-500 has a very precise presentation, with very focused imaging and soundstaging. Bass is nimble, tight and deep, but drier compared to most of the other power supplies on test there. Subjectively, music sounds brighter with a noticeably uplift in treble energy and "air". Vocals also have a subtle degree of projection. Music has a very crisp presentation to it, although vocals have more sibilance compared to the rest of the power supplies. 

Uptone Audio JS-2 - USD 925

The JS-2 has two independent and separately adjustable regulated outputs ranging from 5-12VDC with 5A current capability. Uptone took the unusual path of using a choke filtered power supply, an approach that is more commonly used in tube equipment and is less popular due to the increase in weight and cost. You get two power supplies for the price, which makes it easier to swallow.

6-9V Power Supplies

Meanwell GS25A07 - FOC

This is the stock power supply that is bundled with the Uptone Audio Ultracap. The model is discontinued, but the successor retails for around USD20. Voltage is 7.5V and the current rating is 2.93A.   

Uptone Audio Ultracap LPS-1 - USD 395

Based on super or ultra-capacitors, the LPS-1 was a ground-breaking product at its time. Voltage is selectable between 3.3, 5 and 7V with 1A current rating. Charging and bank-switching is handled by a microprocessor.

Uptone Audio Ultracap LPS-1.2 - USD 435

The successor to the LPS-1 covers voltages between 5 and 12V. Current rating at all voltages is 1.1A. New output voltage regulators are used in parallel to reduce noise as well as output impedance. 

To be continued ... 


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