Rubycon Black Gate VK 150uF/350V, VK 22uF/350, WKZ 100uF/500V

Audio Note Kaisei Polar 100uF/500V, Non polar 50uF/500V




Black Gate (BG) capacitors, known for their unparalleled musical performance and relatively high price tag, have been out of production since 2006. The BG capacitors amaze us with extreme quietness, pitch dark back grounds, huge sounds stage, staggering amount of low level musical information and harmonics and spectacular dynamics. While having a cult status among audiophile circles, BG are often misjudged because out of the box the BG capacitors tend to sound the opposite stated above, quite lame and top end less sound associated with typical electrolytic capacitor. The misjudgement often occurs because people who judged them never really heard their true potential given the very long run in time and the required repeated run in after the device has been switched off and particularly being switched off for a prolonged period of time (>3 days). BG caps undergo serious transformation during the first 100 hours of continuous run in time. Once the initial 100h or so pass BG continue to improve becoming closer what I would call close to a perfect capacitor possible in a real world.

KAISEI is the latest offering exclusive by Audio Note UK ought to close the gap in the audiophile power supply capacitor market left by BG.

Both capacitors are/were produced in Japan by Rubycon.


Comparison conditions:

Comparison was made using a pair of identical Signature DACs by SW1X Audio Design.

All capacitors were used in the HV power supply section of the 6N6P/6N30P tube output stage.

All judgements expressed are a result based on a head to head comparison two identical DAC circuits before and after the burn in period of many hundred hours.

 BG pros:

  • Pitch dark background
  • Brutal dynamics and radiant energy across the whole frequency spectrum
  • Addictive mid- bass quality and quantity


BG cons:

  • BG caps are not perfect; they lack clarity in the top midrange end (relative to KAISEI)
  • Many hundreds of hours run in time
  • Availability and price


KAISEI pros:

  • Superb clarity /Transparency/Resolution but retaining warm sound
  • Complete lack of haze relative to BG
  • Silky smoothness in the midrange a la paper in oil foil (PIO) type caps
  • Fluidity in dynamics comparable to solid film capacitors
  • Frequency extension associated with non polar version of BG
  • Sound nice straight out the box with much less run in time needed


KAISEI cons:

  • Not the last word in dynamics and mid bass weight relative to BG WKZ (one of the best sounding power supply caps known to me)
  • Similar price relative to the original Black Gate retail price


In sum, KAISEI are not BG caps but are close in some aspects such as clarity are even better than BG. Clarity and complete lack of haze on the mid top end is a very notable improvement of KAISEI over BG. Overall the new KAISEI are reminiscent of the old out of production Elna Cerafine 350/500V caps where KAISEI offer a significantly better bottom end and midrange qualities. I would rather classify the KAISEI to be an improved cross between BG and the old out of production 350/500V Cerafines. KAISEI are one of the very revealing sounding caps out there.

KAISEI are very promising capacitors indeed. In our book, the KAISEI caps are ones the better in production power supply capacitors available today.

The only downside is that the LF range is lacking fullness relative to BG and the price.

Nevertheless, we all are patiently awaiting the long promised BG replacement and hopefully there will be a further improvement.




SW1X Audio Design Philosophy

Black Gate Capacitors

Informed and Rational Choice

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bruce frederick
bruce frederick

Have you been able to connect the Kaisei non polar is Super E configuration?



Which one is better polar or non polar kaisei in signal path? (100 VDC value) How are they compare to popular caps such as Elna Slimic II or Muse KZ. Thanks


I want to change all caps of AN Conquer. Would it be a good idea to use AN caps for high voltage and black gate or Simlic for all low voltage one which are all below 50v. I love dark and low noise but all other AN quality of mid you described of AN. Best wishes

Lex Barringer
Lex Barringer

This is not really a fair comparison, you need to get the exact capacity, tolerance, voltage and specific use of the capacitors to compare them.Having different uF values will give you different results because you need to change the other components in the circuit to tweak and tune for your application and that’s a problem because that will change the sonic qualities observed and heard.

Ever think of this scenario?


Did you try to by-pass a Kaisai capacitor with a much smaller “high speed” teflon cap. Eg. a 220 microF Kaisai and a 0,1 microF VH teflon. Any suggestion on results?


Hi, what’s your take between BG PK vs AN standard for digital power supply (DAC 2.1x). I have some spare PK’s, but my DAC came with the AN standards on the digital board. Will it be a worthwhile upgrade, thank you.

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