Arizona Cactus
paper in oil capacitors




Arizona Capacitors, based in the US, manufacture highly regarded audio signal capacitors as part of a huge range of both Audio and Industrial capacitors. The Cactus capacitors are made in collaboration with Mr. Shirokazu Yazaki.

There are 3 different versions. They are all similarly priced but vary in their composition of the internal dielectric slightly.
All of them use aluminum foil electrode and are impregnated with high purity mineral oils. The case is hermetically sealed into an insulated electro-tin plated brass tube with glass to metal compression end seals with soft solder to the ends to ensure a complete hermetic seal. The lead outs are tinned OFC copper.





Red Cactus, C85805e
made up of a kraft paper dielectric.

Capacitance / Voltage

Diameter x Length (mm)


Price each
ex.VAT
Price each
incl .VAT
     
 
 
0,10 uF / 600V
15 x 44
 
25.58
30.95
0,22 uF / 600V
15 x 48
 
26.78
32.40
0,47uF / 600V
20 x 61
 
28.31
34.25


Green Cactus, C50313
made up of a kraft paper and Mylar dielectric, with a higher proportion being paper.

Capacitance / Voltage

Diameter x Length (mm)


Price each
ex.VAT
Price each
incl .VAT
     
 
 
0,10 uF / 600V
15 x 44
 
25.58
30.95
0,22 uF / 600V
17 x 52
 
26.78
32.40
0,47uF / 600V
26 x 58
 
28.31
34.25


Blue Cactus, C50309
made up of a kraft paper and Mylar dielectric, with a higher proportion being Mylar.

Capacitance / Voltage

Diameter x Length (mm)


Price each
ex.VAT
Price each
incl .VAT
     
 
 
0,10 uF / 600V
15 x 44
 
25.58
30.95
0,22 uF / 600V
20 x 49
 
26.78
32.40
0,47 uF / 600V
20 x 56
 
28.31
34.25





Arizona Cactus capacitors.


On the very informational web site"Jeffsplace"
Mr. Shirokazu Yazakiof tells us how he came to the development of the Cactus capacitors and he explains the sound differences between the Red, Green and Blue line.

The complete text can be found with the following link: Upgrading of the coupling capacitor: The Red, Blue, and Green Cactus Capacitors, True Fame of Made In USA

Below is a summary of the article.

Simply stated, I have felt the sound and the tone of the Red, Blue and Green Cactus hermetic sealed oil-filled capacitors by Arizona Capacitors, Inc., to be so desirable, and I have loved them for their tone that is full of warmth, depth, and sweetness. The unique very rich and organic mid-low range of these capacitors brings out the healing and the comfort of my favorite music.

Encounter with Arizona Capacitors, Inc.

I would like to describe my lucky encounter with Arizona Capacitors, Inc., in early June of 2010. I had just started to study how to bring out the full potential of our reference Class-D amplifier design, in early 2007. At this early stage, I had reached the conclusion that the quality of the capacitors for the low-pass filter had major effects on the final sound quality of the Class-D amplifier. The low-pass filter is made of a pair of one inductor and one capacitor, and it works effectively in providing the analog signal current for driving the loudspeaker at the final stage of the Class-D amplifier. It needs a particular specified inductor and a signal use capacitor, 0.47µF, and so it would be just like low-pass filter of speaker network, with the only difference being the crossover frequency is around 400 kHz. I suppose you could imagine the importance of the capacitor used in the low-pass filter for getting the most desirable sound.

Thanks to the passion of the forerunner of tube amplifier enthusiasts in Japan, I was able to get easily a lot of types and brands of NOS vintage hermetic seal capacitors, like Sprague Vitamin Q, also Sprague HYREL, Dearbone, Aerovox, West Cap, and others, like the NOS Black Beauty and Black Cat, because of their favor in the consumer market. Searching for nice sounding capacitors has been very interesting work for me, and I found out about the enormous sound potential of NOS hermetic seal oil-filled capacitors that were made for defense use in the USA. By the end of 2009, I had reached the conclusion that my favorite capacitor for use in this filter was a vintage oil-filled capacitors by West-Cap, 0.47/600, that made for the US military in 1967. As a coupling capacitor it also remarkably improved the sound of my old WE310A driven DA30 non-feedback SET, with its sound gaining in musicality and with a fascinating and beautiful mid-low range. It’s a NOS vintage capacitor, but it did not have too much heavy bass or old fashioned tone like the famous Sprague Vitamin Q.

Well, Banno-san (my fellow engineer, who is not only a skillful engineer of analog and digital circuitry even now, but also he plays the piano very much, and has been playing the cello now for more than five years) and I, decided we had to find a currently produced capacitor just like the West-Cap for our Class-D amplifier, when we started Spec Corporation. Thankfully, I was blessed to come across Arizona Capacitors, Inc., at that time, and succeeded in contacting them, the day after founding our new Spec Corporation company on January 7th of 2010.

Type C 85805, Red Cactus

At first we ordered a custom capacitor made of only Kraft paper and aluminum foil that was our prototype of the Red Cactus. Yes, the Red Cactus is a genuine paper in oil (PIO) hermetic sealed capacitor. On March 15th of 2010 we received the first samples from Arizona Capacitors. With these samples, we were able select several oils to try for impregnation, to hear which best fit the sound we desired. The first Red Cactus’ tone was very impressive for us, and the mid-high range was simply fascinatingly beautiful, so pure, and sophisticated.
The tone might fit best for chamber music, especially for violin and female vocals, I believe. That’s why I called it Red Cactus, as the attractive tone reminded me of a certain beautiful Hollywood movie star from the old days. Even now, we use this Red Cactus as the main capacitor in our top of the line amplifier, the RSA-F33EX, and the Red Cactus is Banno-san’s personal choice for its pure tone.

Type C50309, Blue Cactus

The type C50309, which I called the Blue Cactus, was developed to compensate for some of the weakness in the low range of the Red Cactus. The dielectric materials of the Blue Cactus are made of the combination of Kraft paper and Mylar film. Accordingly the construction of the Blue Cactus was just the same as the vintage NOS West-Cap, which I so loved. The greatest virtue of the Blue Cactus is its recreation of the rich and powerful sound of the vintage hermetic seal capacitors made in USA, and so the sound has a gorgeous and strong mid-low range.
Of course, the sound of this Blue Cactus surpassed the vintage West-Cap with the transmitted signal information, especially in the mid-high range. In other words, we could say the dynamic S/N ratio and frequency range, were much improved to our hearing, I felt. We have also mainly used Blue Cactus capacitors in ourRSA-M3EX amplifier, and I suppose the rich timbre and the massive sound of M3EX owes much to the Blue Cactus capacitor. I named the Blue Cactus capacitor after the vast clear blue skies of Tucson, Arizona, that I experienced at the Pima Air & Space museum, when I visited on October 3rd in 2015.

Type C50313, Green Cactus

The type C50313, Green Cactus capacitor, was released in the summer of 2014, as our latest Arizona Capacitor. I wanted to achieve a brand-new sound for a hermetic seal capacitor, and Daryl-san’s (the former general manager of Arizona Capacitors, Inc.) idea was to increase the thickness ratio of Kraft paper to Mylar film. Our goal was that the tonal character, from mid to high end, would be close to the sound of the Red Cactus capacitor, a genuine paper in oil (PIO) capacitor, but with the added benefit of a mid-low range that would be like the Blue Cactus capacitor. It turned out the sound of the Green Cactus capacitor was nothing like a vintage capacitor’s sound, and the Green Cactus capacitor has a clarity through its entire exceptionally wide range. I feel somewhat like the Green Cactus capacitor has the sound of the best polypropylene film capacitor, but is still very organic and natural sounding, which is something polypropylene film could never achieve at that level. And so I believe, this Green Cactus capacitor could easily fit in well for a high-resolution music source in the present day. When I named the Green Cactus, I was thinking of the majestic scenery of Yosemite National Park in California, filled with granite cliffs, waterfalls, clear streams, and its beautiful giant green sequoia groves.

Cactus marking and Outside Foil

I would like you to know the true meaning of Cactus marking, printed on the Red, Blue and Green Cactus capacitors. This Cactus marking is the old logo of Arizona Capacitors, Inc., and the marking side shows the outer foil of the capacitor. The outer circumference of a tubular capacitor’s body must inevitably be one side of its electrode, and this is called the outer foil. The outside foil is connected to one lead wire of the capacitor, and of course the inner side foil is connect to the other lead wire. Sometimes inductive noise can be induced on the outside foil by some kind of external electrical condition, but when the lead of outside foil is connected to ground, the inductive noise flows into the ground. Also, it is better to install the lead wire of the outside foil into the lower voltage side, or closer to ground.

When you use Red, Blue and Green Cactus, Arizona Capacitors, let me remind you that each Cactus marking points out the end of outside foil, and these capacitors have been produced and managed under the quality control of Arizona Capacitors, Inc. to be labeled in such a way.

Physicality of Raw material and Tone Characteristic of Capacitor

I remember well, when Banno-san said to me in early January 2010, after his hearing comparison test of a lot of types of capacitors, including the latest high quality polypropylene capacitors, that “It is just like I heard the sound of the mechanical vibration, or some kind of resonance, of the raw materials of each type of dielectric or electrode itself.” Banno-san could very clearly hear how the capacitor’s raw materials have much affect on the mechanical and sound character of each capacitor, I think.

Well, the capacitor for signal use works like this: The signal voltage is superimposed on the DC that flows into one side of the capacitor’s electrode, and the capacitor blocks the DC so that only the signal current is at the other side of electrode. In this filtering process, the fluctuation of the electric charge produces mechanical vibration on the dielectric and the electrode. This kind of vibration leads to a modulation of the signal as it flows through the capacitor, I understand. For this reason, the raw material of the dielectric and electrode will be be very influential for the tone characteristic of the capacitor.

I fully agree what Daryl-san once said to me, that “Capacitors manufactured with exclusively film, such as polyester, polypropylene, Teflon, are described as fast responding, often associated with harsh tonal quality. Additionally, these (typically) dry units also exhibit sonic resonant tendencies that can also yield unwanted effects on the sound quality. Oil filled or impregnated capacitors tend to dampen this effect, giving superior tonal qualities. In addition, by combining various ratios of Kraft paper and film, the tonal qualities can be manipulated to a desired effect.” In the sound of the Red, Blue, and Green Cactus capacitors, I recognize the common desirable and comfortable tone character in these capacitors, which partly comes from the from the character of the Kraft paper. I suppose you know very well that high quality Kraft paper is made of genuine pulp, and the main raw material of the pulp is from a conifer tree. When I think of such a conifer, I’m also reminded of the simply natural and comfortable low range of my Altec 414A, which I have loved so long a time. The fabric the woofer was made of is the highest quality pulp from conifers with a long fiber length. I regard Kraft paper as exactly the same sort of natural material, and so it comes as no surprise that the tone of the Kraft paper is organic enough that it warms my heart.

At present, undoubtedly metalized polypropylene capacitors are the mainstream capacitor for signal use in speaker networks. I fully agree that metalized polypropylene capacitors have a modern and very neat tone, with fine details and resolution, and I know very well that this sort of sound might be accepted and highly appreciated by a lot of music lovers around the world.

But I have felt the tone of metalized polypropylene capacitors don’t have the natural warmth of human touch, and lacks the true naturalness of the hermetic seal oil-filled capacitor that is made of mainly Kraft paper as the dielectric. I suppose it might come from the fact that the frequency also has a level of characteristic vibration, and with polypropylene it would be higher because of the high Young’s modulus (hardness) and the small value of internal loss. I think the metalized electrode might emphasize the tendency.

About the foil of an electrode, Banno-san and I, had experienced the tone of aluminum, tin and copper under the condition of the same dielectric material and oil. Tin foil’s tone, we felt was insensitive and cloudy. The tone of copper foil was too rich for timbre for our hearing. We selected aluminum foil because of its natural and organic tone for the Red, Blue and Green Cactus capacitors.

Once again, we found out the importance of balance between hardness and internal loss. Well, I would like to point out again that while our hearing senses can easily recognize these differences in tonality, there is not any measuring method or tools that can describe why this is so. There is much that is unknown about the world of physical properties and the mysteries of natural materials, and so listening must be one of our truths for analog technology, I understand.