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November 2007
Enjoy the Music.com Review Magazine
CSE Isolation Regulator RK-100
Review By Wong Kok Chieat
Click here to e-mail reviewer


CSE Isolation Regulator RK-100  In certain parts of the world, due to geographical reasons, many products just could not get enough coverage and exposure that they more than deserve. At times, audiophile consumers over here in Singapore and Malaysia have limited choices. Even when more and more people are willing and confident to trade online, some brands are just so remotely unreachable!

This is especially true for audio products from Japan, not so much on Japanese cars though. The lack of exposure is not due to their remoteness on the map. In fact, there are just so few places we could not reach nowadays. The lack of exposure for Japanese audio products is due solely to one reason. That is majority of the Japanese brands are reluctant to do export for their products. Indeed, the Japanese audio scene had practiced closed market for many years. They are mainly catering to domestic needs, rather than open for international markets.

It was not until recent years that brands like TAOC, Oyaide, Acrolink and CSE started to crop up in Asian markets like Hong Kong, Taiwan and Singapore that people started to get excited and curious over the Japanese products. TAOC is no stranger for people serious in isolation and support products. The same applies for Oyaide on connectors and receptacles, while Acrolink is well known for their high purity stress free copper cables.


The Company

The matter for review is the RK-100 AC regenerator from CSE. A search on the Internet returned results mainly in Japanese, which I do not comprehend at all. Lucky the CSE products are selling quite well in Hong Kong that I managed to get some Chinese write ups. Let's start off with a bit of background on CSE.

CSE stands for Chubu System Engineering. The company has got their root deeply planted in R&D for power products like power cords, isolation transformers and AC regenerator. Even with 20 years of history, its exposure in western countries is almost non-existence. In Japan, CSE has domestically garnered a name for itself from its power conditioning products.

There are basically two types of products from CSE's power cleansing solutions, namely the Isolation Balanceformer and the Isolation Regulator. The Isolation Balanceformer is none other than a balanced power supply, but what sets them apart is the high quality WB transformer employed within. Compared to traditional EI transformer, WB transformer differs in winding method, which accordingly yields higher magnetic efficiencies. Do a search for WB transformer and you could understand more about the structure of this design.

The Isolation Regulator, which is what under review today, is basically turning incoming AC to DC, and subsequently regenerating the DC back to AC again. This is not new technology as it has been employed back during the World War II time. It was brands like PS Audio and Accuphase that brought it to audio usage. Do correct me if I am wrong as I remember reading elsewhere that they are not the first.


The Product

The RK-100, upon unpacking, exudes sturdy build quality with no nonsense, industrial design. This reflects Japanese's down to earth nature and focus on practicality rather than eye candy appeal. The front fascia is 0.8mm of solid aluminum with "CSE Isolation Regulator RK-100" nicely printed in the center, in three separate lines. Directly below is where you could find two flip switches and three different colored LEDs.

The left one is a two-position flip switch where when flipped up gives you 60Hz of pure and clean sine wave. When needed, you could flip it down to give out equally clean and pure 50Hz sine wave. This is especially useful to analogue buffs where 50 Hz maintains rock steady spinning RPM to their beloved turntables. Use this if you don't want to listen to chipmunks sing.

The right one is basically a three-position switch with up as Operate, down as Through and middle as Off. The green LED lights up when in Operate mode while the yellow lights up when in Through mode. The red one would light up when the unit is running out of steam. Bear in mind that the unit is limited to only 100W of capacity. The Through mode sets the unit in bypass mode, which is particularly useful if you always keep your front end in stand by mode. This helps in preserving the lifespan of the RK-100 as well as saving electricity bill. RK-100 consumes 50W even when idling.

From the back, there are one IEC receptacle and two US type outlets. There is an Output Voltage Selector clearly marked as Normal Voltage or Special Voltage. The Normal Voltage is nothing more than outputting at 220V while the Special Voltage just outputs at 230V. I had mine set to Special Voltage, which is 230V, to fit my 230V Rega Apollo CD player. The RK-100 is powered by Harmonic Tech's Fantasy power cord while Stealth Cloude Nine Full is used from RK-100 to power the CD player.

From the feel of connecting the RK-100 to my existing setup, the snugly fit receptacle and outlets confides me further in Japanese reliability. I have no doubt in its usefulness in my setup. In fact, the unit runs mildly warm even without air conditioning. Heat dissipation is good with the unit returning to room temperature in about ten to fifteen minutes from the moment it is turned off. I have mine running 7/24 more than a week for running in purpose.


The Sound

Prior to putting the RK-100 in action, my setup is already open sounding with a balanced frequency response. Music played with lifelike rawness and moved "freely" as the Bladelius Thor MKII integrated amplifier delivers ample guts to my ATC SCM20T. The inherent shortcomings are just due to the Rega Apollo CD player. While no slouch in its own price class, the rest of my rigs just show its limited low frequency quantity and recessed high frequency. Anyway, we are not going to be bogged down by this, aren't we?

Since I am covering the audio scene in this part of our Asian continents, I am going to use software more widely listened here. It's not that we could not get great software often used in printed publications; I just feel that we could relate more to the ones we use in this part of the world. And I often use Chinese pop CDs to test rather than audiophile approved CDs. I find that at times, it is much harder to reproduced pop CDs in a balanced manner. On the other hand, the chances of Audiophile approved CDs sounding bad is just so minimal.

The first run, I used Miriam's latest collection album [Gold Label 5099951190927] where she sings recent hits in the Hong Kong pop scene. In track 2, the arrangement is just a simple piano accompanying Miriam's singing. With the RK-100 switched to Through mode, the piano sounded dry, dull and simply decayed prematurely. When switched to 60 Hz mode, I was greeted with piano notes that sounded so weighty, full, tangible and rich in harmonic overtones.

Vocal snapped into sharp focus and took a more bodily presence. The vocal energy emerged more concentrated from the middle. Without RK-100, Miriam seemed not able to pull her act together. With RK-100, Miriam sung with greater attentiveness and emotions. At the same time, it was easier to dissect the fine details in Miriam's singing and the gradient of her vocal strength has got better micro-steps. There was more refinement in the outline of Miriam's vocal and the flow was more effortless.

In track 4, playing without the RK-100, the presentation seemed a bit lethargic. With the RK-100, the drummer has got a better grip and contributed greatly in capturing the correct intensity. The track became so much more enjoyable with the correct pace. However, it was in this track that I discovered the effects of RK-100 running in 50 Hz mode. When switched to 50 Hz, the presentation opened up considerably.

The presentation took a slightly thinner manner; the highs took a more sparkling appearance. There was more attack to the high hats and the leading edge was more pronounced. The overall frequency response was lifted upwards with greater high frequency extension. The low frequency took a slight compromise in quantity but remained solidly planted. Vocal came out slightly thinner with more pronounced sibilance, but it was never unbearable. However, the sibilance was never worse than running in Through mode, it might be due to the reduced richness that brought about the perception of more pronounced sibilance. With 50 Hz, music played at greater dynamism, yet, never compromised in refinement.

Next up, I played A Pan's latest album [Logistic Entertainment LE-001]. Pan Yue Yun is a veteran singer from Taiwan, in this album, she sings some of her best work in new jazzy arrangements with 96 Khz/24bit mixing and mastering. Not only this, the album was recorded in a concurrent manner where the singer and musicians performed simultaneously. Any mistake would mean starting all over again.

For this album, I played only in 60 Hz as I found it to be having the most balance with top, middle and bottom frequency response evenly distributed. And music played with more composure and finesse, too. There was just no way could I switch back to running direct from the wall. At first, running without the RK-100, one might perceive the songs played more dynamically with better lifelike rawness. Upon switching the RK-100 to Operate mode, you would realize why in the first place you ventured into this hobby.

Just right after I pressed play, it was like I have been transported to the venue. Everything emerged from pitch-black darkness. The percussionist played with such agility and tautness. Piano played in such direct manner that at times, I could feel it playing in front of me. The kick drum was presented with great authority and force, lending a solid beat to the songs. With RK-100 in operation, one could actually "see" the oscillation of the double bass strings. Above all else, listening to this kind of recordings helped in appreciating the correct tonal accuracy, RK-100 just brought this to a heightened revelation!

Micro dynamic improved by leaps and bounds, yet, this improved resolution came with great smoothness and refinement. As Pan Yue Yun sung in great force, one could listen deeply into her emotions; as she trailed in frailty, it moved you immensely that you could only gasp in desperation! Singer-listener interactions became so direct that the rigs just disappeared, leaving only the music and the listener. By putting the RK-100 to Through mode, all these liquid qualities just went out of the window.

Next up, I played White Snow in Early Spring by Wong Ching [HUGO HRP 7188-2], a veteran musician playing pi-pa. You would not fail to find this in many audio shops in this part of the world. Here, depending on the context of your setup, one could either choose 50 Hz or 60 Hz operation.

Just by playing the first track, one could tell a lot about the setup. Indeed, we only play track 1 if we ever use this as a test disc. With the RK-100 set to 60 Hz, similar to early observations, the pi-pa took a more bodily presence. However, the pi-pa did not emerge singularly in a tiny vertical space, but one could perceive the minute differences between the horizontal distances of the strings. The strings have got such substantial and bouncy quality to them.

Towards the end of the track, there would be a gradual build up of speed and intensity. The RK-100 brought about huge improvements in terms of micro and macro dynamic, in addition to that, the gradient in the in-between levels were also vividly presented. The drum behind was fast and full as it played with increased strength. The reverberation was also accurately reproduced that the seamless fore and aft continuity was laid bare in front of you.

By just a flip of a switch to 50 Hz, the presentation became more forward and snappy. There was more leading edge to the drum at a slight compromise in fullness. The "ease-ness" in 60 Hz was replaced with a more crispy, immediate and sparkly presentation. Depending on mood and the nature of your setup, one could easily find the best fit.



Even as I am using a less than ideal CD player while waiting for my Bladelius Freja SE multi-format player, I am reaping tremendous improvements from the addition of CSE RK-100 into my setup. Mind you though, this is a unit that I bought even before the invitation of writing reviews for Enjoy the Music.com. I have been contributing a while to a local audio blog, and all these while I have been writing on stuff that I have bought with my hard earned money. Also note though the unit vibrates internally, and differently when set to 50 Hz or 60 Hz operation. However, the transformers do not produce alarming hum even when I put my ear virtually sticking to the unit. The rubber feet are adequate in isolating the unit, but as all anal audiophile would do, I will be adding some isolation feet to see if I could improve further in mileage.

I suffered many a time from buying solely based on reviews, but for the CSE RK-100, it earned my unreserved recommendation. I hope you could benefit from it also!


Associated Equipment

Source: Rega Apollo CD player
Amplification: Bladelius Thor MKII
Speakers: ATC SCM20T
Speaker cables: AQ DBS Mont Blanc
Interconnect: AQ DBS Cheetah
Power cords:
   Oyaide Tunami GPX for amplifier
   Harmonic Tech Fantasy for RK-100
   Stealth Cloude 9 Full for source



Sub-bass (10Hz - 60Hz)

Mid-bass (80Hz - 200Hz)

Midrange (200Hz - 3,000Hz)

High-frequencies (3,000Hz on up)



Inner Resolution

Soundscape width front

Soundscape width rear  
Soundscape depth behind speakers

Soundscape extension into the room


Fit And Finish

Self Noise

Value for the Money



Type: Electrical isolation transformer
Input Voltage: 220V
Output Voltage: 220V or 230V
Output Power: 100W
Output Frequency: 50Hz or 60Hz
Power Outlets: 2, US type
Power Consumption: 50W idling
Dimensions:  217 x 93 x 379 (WxHxD in mm)
Weight: 8 Kg.
Listed Price: SGD 1,900 (or JP¥89,000 tax included)


Company Information

CSE, Chubu System Engineering
Voice: 0584-89-7791
Fax: 0584-89-5696
E-mail: host@cse-inc.co.jp
Website: www.cse.ne.jp 













































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