Degawa Power Supply Modules

During mid-2000s, Mr. Saburo Degawa introduced his newly designed power supply circuit that he named as the Second Generation Series Power Supply.  He presented papers at AES Convention in Tokyo, and published articles in “Audio Technology MJ Musen to Jikken” and “Radio Gijutsu”, premier monthly magazines for technically oriented and DIY audiophiles in Japan.  Measured and computer simulated results presented by Degawa showed 46% reduction in ripple (according to the Patent document) and up to 200 fold reduction in rectifier induced noise level compared to conventional bridge rectified power supply circuit; and output impedance lower than that of a typical battery based power supply. His new design, commonly referred to as Degawa PS (power supply), was extremely well received by the Japanese DIY audiophile community and created a bit of a quiet sensation amongst those in the know who expressed significant sound quality improvements.  Saburo applied for and was awarded five patents between 2005-2007 associated with his PS design.  His patents are licensed to some of the notable Japanese HiFi manufacturers including Esoteric and Acoustic Revive.  His own company, A&R Lab, produces Degawa power supply components/modules primarily aimed at the DIY audiophile community in Japan.  Jean Hiraga introduced Degawa PS at European Triode Festival 2014.  Jean is a well known French HiFi journalist who was noted as a legend in the world of audio publishing by Sixmoons. com (https://6moons.com/industryfeatures/hiraga/hiraga.html). 

 

About Mr. Saburo Degawa

In Japanese, a masculine given name Saburo, signifies that he is the third son of the family.  A graduate of Tokai Communication Engineering Technical College, Mr. Saburo Degawa had a long and successful career of over 40 years in product development at International Rectifier Japan Company Limited (IR Japan) a subsidiary of International Rectifier which is now part of Infineon Technologies AG (https://www.infineon.com/ ), a spun off of Siemens AG, one of the world leading semiconductor manufacturers.  IR Japan was credited as the first company in Japan to develop and manufacture silicon rectifiers. The company is now a part of the Kyocera Group, a Japanese multinational ceramics and electronics giant (https://global.kyocera.com/).

 

In the hay days of consumer electronic appliance manufacturing industry in Japan, Degawa was assigned to projects to develop of fast recovery diode rectifiers and Schottky barrier diodes for HiFi equipment specifically design to improve their sound quality. Being an avid audiophile and a music lover himself, these assignments lead him to begin tinkering power supply units of his own stereo gears on his spare time.  Upon retiring from IR Japan in 2003, Saburo established his own company, A&R Lab to market electronic parts and components. and offered equipment modification services for audiophiles.  At the same time, he continued to refine and prefect his power supply designs obtaining the patents.  

 

Degawa Power Supply

I am not an electronic engineer but just an avid DIY audio enthusiast so, I will try my best to explain technical aspects of Degawa Power Supply but if you notice any errors, please forgive me and feel free to send me a kind email notifying me of the error(s) J.

 

In a nut shell, Degawa PS incorporates a”Sub-Rectifying Circuit” which generates additional rectified DC current that compensates for voltage drops of the main rectifying circuit as seen in the two oscilloscope screen shots below (figures 1 and 2).  Saburo’s ingenuity was to include measures to help ensure that the two rectified currents integrate seamlessly compensating each other’s voltage drops.  This was achieved through choice of rectifier diodes with different recovery times; add components (e.g. resistors/inductors/diodes) to match impedances and adjust phases of the two rectified DC current streams.

Fig. 1 Conventional rectifier circuit 

(Source: Hiraga, Jean, “AC line and electronic audio devices, their mutual noise pollution effects”, a presentation at European Triode Festival 2014, Berlin, Germany)

 

Fig 2: Degawa Power Supply circuit

 (Source: Hiraga, Jean, “AC line and electronic audio devices, their mutual noise pollution effects”, a presentation at European Triode Festival 2014, Berlin, Germany)

 

Degawa PS module is produced by Saburo’s A&R Lab. New Generation rectifier modules (as he calls them) are designed to replace variety of conventional PS  devices and circuits.  There are many models offered to meet variety of rectifier topologies based on solid states and vacuum tubes rectifiers with varying voltage and current rating. 

 

Fig. 3: Various Degawa PSU Modules: New Generation rectifier modules (Front)  and LCMs and CPMs.

 

 

Degawa PS module is produced by Saburo’s A&R Lab. New Generation rectifier modules (as he calls them) are designed to replace variety of conventional PS  devices and circuits.  There are many models offered to meet variety of rectifier topologies based on solid states and vacuum tubes rectifiers with varying voltage and current rating. 

 

Below  is a simplified schematic diagram of a full wave bridge rectifier replaced with Degawa Rectifer module.  All of the Degawa rectifier modules require an additional capacitor (Cx above) to be installed.  The recommended capacitance of the Cx is about the double the capcitance of the original capacitor (C above).

 

Fig. 4:  Simplified example schematic of Degawa PSU

Source: A&R Lab

 

In addition to the Degawa New Generation rectifier module, there are two complimentary components: LCM (Line Control Module) and CPM (Capacitor Potential Module) primarily aimed to further reduce noises from rectified DC power. 

 

Fig. 5:LCM  Installed 

While no technical information is disclosed, LCM act as a filter just like the so called pi-filer (choke/ resister or capacitor/resistor).  Mr. Degawa claims its effect as in the chart below.  Where red line represent using typical “Pi” filtering and the green line presents using LCM.

 

Fig. 6: Noise spectrum Fourier analysis comparison on rectified power supply

LCM (green) vs Conventional bridge rectifier and resistor capacitor filtering (red dotted) 

(Source: Degawa, Saburo, Presentation at Japan Triode Meeting in Fukuoka, May 2017)

 

Fig. 7:  Installed CPM 

 

 

CPM on the other hand is aimed reduce noise by filtering and re-directing noise induced by back electromotive force (BEMF) and counter-electromotive force (CEMF) to ground and recovering positive current into circuit. 

Fig. 8:  Simplified example schematics diagram of fully fitted: 

Degawa Rectifier Module + LCM+CPM

Source: A&R Lab   

 

How's the sound?

There are so many different designs, tweaks in the hobby of HiFi/Audio with claims of objective/subjective improvements on sound.  For example, variety of cables (analogue/digital), curved traces on PCB, audiophile grade capacitors, audiophile grade fuse, cryogenically treating parts, solder infused with precious metals, and components, insulators, Bybee quantum purifiers, nano  etc.  Most of them, considered as dubious at the time of introduction, but many eventually gained acceptance. With almost 40 years of being immersed into this hobby, I now try to keep an open mind.  But I try not to judge things until I actually hear them.  If I am intrigued enough with a particular tweak that compels enough then I will try it.  When I try, I ask my family members to take a listen to see if they could hear the difference and if so, whether they like the change.  This helps my prejudice of favoring the tweak just because I may have vested interest to justify the cost.  Having an open mind, ultimately, helped me to improve the sound of my system.

  

Fig. 9: Installed Degawa Rectifier Module for the heater PSU

of Audio Note Kits L3 Pre-Amp 

 

When I first heard about Degawa PSU, around mid-2000s, naturally I was skeptical.  I decided to try only after a very close audiophile friend who writes for Japanese HiFi magazines enthusiastically endorsed Degawa modules.  Even then, I only took a small first step.  I purchased two CPMs because they were the cheapest of the Degawa modules.  I used them in digital board PSU of my AudioNote Kits DAC3.1 Signature.  I was pleasantly surprised with the outcome.  The sound become smoother less grain and and less brightness, at the same time, I was hearing more details of the recordings.    

 

After this experience, I installed CPM in my Audio Note Kits L1 Phono stage subsequently to my Audio Note Kits L3 Preamp and the results were consistent.  Eventually, I installed LCM, then the rectifier modules to the heater PSU circuits.  I have experience varying degrees of clearly notable improvements in the direction as listed below consistently with each and every addition of Degawa PSU modules:

  • In general, sound become:
    • more natural with more realistic timbre of human voices and acoustic instruments;
    • more clear and details and at the same time increased amount of warmth; and
    • less harsh/bright and significantly reduced listening fatigue from not so well recorded/mastered recordings;
  • Improved tightness, definition and substance of bass; 
  • Improved detail retrieval at low volumes and the sound can be played louder with less constraints.  

 

Fig.10: Degawa Rectifier Module is also available in Vacuum Tube like casing (above is  a larger casing).  Please note that it is not a plug-and-replace module.  Modification to add capacitor is still required ( see Fig. 5 above)

 

The biggest surprise came when I installed Degawa rectifier unit to my Power Amp’s (Audio Note Kits Kit One) B+ power supply.  First I was surprised by the improved level of weight and definition of low frequency notes.  Double bass and bass drums not only sounded more substantial but it clearly improved definition. Resonance from the body of the bass and attacks on bass drum are much easier to discern.  Human voices gained more substance as illusion of a singer between the two speakers sounded a bit more real.  A spatial rendition improved adding depth and width to the soundstage.  The overall outcome was that improved illusion of the music is being played in the room as opposed to sound coming from two speakers.  This was a change from tube rectification (5U4GB).  I always believed that tube rectification was better than that of solid state.  But replacing tube rectifier with Degawa PS was a revelation and completely changed my mind.  Overall, the changes resulting from Degawa PS module is like upgrading one’s equipment the next level but without drastically changing their sonic character.  My Audio Note Kits equipment retained the so called “house sound” of Audio Note UK that I am very much fond of but almost all sonic quality attributes were improved.

 

Fig.11: Degawa Rectifier Module smaller Vacuum Tube like casing.  

 

I hope I made you curious about Degawa power supply enough for you to want to try them.  I do understand that making such a decision without listening would be like taking leap of faith.  But I believe, this is something many of us who are into DIY HiFi often do, because to experiment is the only way to find out if something would help improve the sound of your system to your liking or not.

 

How/Where to buy Degawa PSU modules

Before reading any further, please note that I am not affiliated or related in any way or form to Mr. Degawa, A&R Lab or any of its retailers that handles their product.  Also, I have not and will not receive any incentives, financial or otherwise, from Mr. Degawa, A&R Lab or any of its retailers and affiliates. I am adding this section because my target readers of this webpage are the DIY audiophiles living outside of Japan and Degawa PSU modules, at the time of this writing are only sold in Japan.  I would like to introduce a way purchase Degawa PS modules from where you may be. 

 

Although I am originally from Japan, due to my work, I had live outside of my home country for over 30 years.  Therefore, just as the readers may be, I also had to find a way to purchase Degawa modules from outside of Japan.  The particular retailer I used was Pract Sound System which is a web only store (http://www.practsoundsystem.com/) that is in business for almost twenty years. Its proprietor, Mr. Nagahisa Okamoto, is an avid audiophile himself and has a day job of being an electric engineer catering to utility companies working at one of the major industrial manufacturing companies of Japan.  The way to place an order is to send him an email with your requirements (i.e. which module you wish to purchase, quantity and the voltage/current rating required, where it is to be shipped to etc.) and  Mr. Okamoto will reply back with his price estimate including shipping and paypal fees.  He ships via International Express Mail Service.

 

Perils of Do-it-Yourself HiFi equipment modification

 

I have installed Degawa PSU modules in most of my HiFi equipment and I am very happy with the results and experienced no issues so far.  So, I don’t mean to deter you from tying the Degawa PSU modules, but to I would just like to remind the risks.  I would consider modification using the Degawa PSU is for the well skilled DIYer’s because it is a modification to equipment’s power supply which could be hazardous due to the high voltage that are often involved.  So please do it with extreme care. Needless to say, any modification will not only void manufacturer’s warranty but a manufacturer is likely to refuse repairing modified products. Therefore, please proceed with modification at your own risk. 

 

 

Links

A&R Lab: http://www7b.biglobe.ne.jp/~degawa/

 

An audiophile passion (Une passion audiophile): A French audiophile, Dominique-Tanguy's blog about  HiFi.  He has build a 211 SET amp with Degawa modules: http://unepassionaudiophile.fr/laventure-du-set-211%C2%B2/

 

(This page was added on 06 Sept. 2019)

 

Hifi power supply, audio note kit, audio note kit one, black gate capacitors, VCap, CuTF, European Triode Festival, Jean Hiraga, Saburo Degawa,