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TEST ACUSTICI SUI CONDENSATORI AUDIO (RASSEGNA DI TUTTI I MODELLI DISPONIBILI)

Humble Homemade Hifi


Capacitor Test

The subjective results of this test are meant to give you a basic idea of the sonic differences between capacitors when used in loudspeaker filters. I test all the capacitors in the signal path of tweeter and midrange circuits in loudspeaker crossovers and try them out in both series- and parallel crossovers. The capacitors are tested in different loudspeakers, varying from the ones I happen to be building at the time to the many demo speakers I have. I also use solid-state and tube amplification, analogue and digital source equipment and several different interlinks and speaker-cables during the process of evaluation that takes several months of extensive listening. Testing is done by listening to various good quality recordings on CD and vinyl and everyday high Kbs streaming internet radio. The evaluation consists of listening with just one pair of capacitors (so no switching) over a longer period of time. This is then repeated with a different capacitor. This way I get a good idea of what each capacitor does and doesn't do. Finally I do direct comparsions with previously tested types to determine the rating. Over time I may re-evaluate my previous conclusions as new capacitors enter the contest. I give each participant a rating. This scale is based purely on sound quality; price has been left out of consideration. A higher rating does not automatically mean that one capacitor is better than another. A hi-Fi system is a very complex sum of many variables, a capacitor is only one part of that total, so depending on implementation things may vary a little. On the other hand you can be assured that capacitor A with a 6 point rating won't "beat" capacitor B with a 10 point rating.

Why do capacitors sound different?

In the past capacitors were just capacitors and sound quality was determined by the dialectric material with polypropylene considered by many as "the best" seeing as this type of capacitor had the lowest losses. But technology of the 21st century has brought us new measuring techniques and insights and there seems to be more to it. We can now measure things that were not possible a few years ago. In a nut-shell: microphony is the keyword - the mechanical resonance, a key feature of audio capacitors. This is a physical deformation of the capacitor walls which occurs as a result of the audio signal passing through the component – much like an electrostatic speaker. This resonance is dependent on the size, shape, materials and manufacturing parameters of the capacitors. This effect has been known about for years as it plays a part in the impulse strength of capacitors. However, the effect has never been considered to be significant enough to affect a hi-fi system’s audio reproduction due to the low energy involved. For more indepth information read the Clarity Cap white paper on mechanical resonances inside capacitors. Another interesting article was written by Martin Colloms back in 1985 in which he tested several capacitors on their sonic differences. Also look at the equivalent circuit diagram of a capacitor, this also explains a lot. A capacitor is more than just capacitance C!

So far I have tested the following capacitors (in alphabetical order):


Amp Ohm FP-CA-AU polypropylene

Amp Ohm PF-XAL-AL alu / paper in oil

Amp Ohm PF-XAL-W-AL alu / paper in wax

Amp Ohm FE-XAL-AL alu / polyster in oil

Ansar CPA polypropylene 450VDC

Arcotronics MKP-C-4G

ASC X386S MKP in oil

Audience Auricap MKP *

Audio Cap PPMF MKP

Audio Cap Theta PPT MKP-Sn

Axon True Cap

Cicada Pure Aluminium Foil 100VDC

Cicada Pure Copper Foil 100VDC

Clarity Cap PWA

Clarity Cap APW

Clarity Cap PX

Clarity Cap SA

Clarity Cap ESA

Clarity Cap MR *

Clarity Cap DTAC

Ducati 4.16.10 MKP

Duelund VSF Cu-foil / paper *

Duelund CAST Cu-foil / paper in oil *

Duelund RS Cu-foil / paper in wax *

Epcos B32523-Q3475-K26 MKT

Epcos B32656-A6475-J MKP

Epcos B32774-D1505-K MKP

Erse Pulse-X 630VDC

Erse Transient-X 1200VDC

Evox-Rifa PHE 426

Evox-Rifa PHE 450

Evox-Rifa SMR

Hovland MusiCap

Hovland SuperCap (Robert Hovland Series) *

Inco Sintex 45T D2BS

Intertechnik Audyn Cap FFC alu-foil PIO

Intertechnik Audyn Cap Kp Sn

Intertechnik Audyn Cap MKP-QS

Intertechnik Audyn Cap Plus

Intertechnik Audyn Cap Reference *

Intertechnik Audyn Cap True Silver

Intertechnik Audyn True Copper Cap *

Jantzen Audio Cross Cap 400VDC

Jantzen Audio Standard Z-Cap

Jantzen Audio Superior Z-Cap *

Jantzen Audio Silver Z-Cap

Jantzen Audio Silver Gold Z-Cap

JB Capacitors JFX 250VDC

JB Capacitors JFX 630VDC

JB Capacitors JSX 250VDC

JB Capacitors JSX 630VDC

Jupiter HT BeesWax Paper Cryo

Jupiter Flat Stacked Beeswax Cryo *

Le Clanché PPM MKP *

LCR FSC tubular foil polystyrene

Mundorf MCap 250VDC MKP

Mundorf MCap 400VDC MKP

Mundorf MCap 630VDC MKP *

Mundorf MCap RXF

Mundorf MCap EVO Aluminium 450VDC

Mundorf MCap EVO Aluminium/Oil *

Mundorf MCap EVO Silver/Gold/Oil

Mundorf MCap Supreme Cap *

Mundorf MCap Supreme Silver/Oil *

Mundorf MCap Supreme Silver/Gold

Mundorf MCap Supreme Silver/Gold/Oil *

North Creek Crescendo Film and Foil

Obbligato Aluminium Foil *

Obbligato Film Oil

SCR Châteauroux MKP-PB

Solen Châteauroux Fast Cap PB-MKP-FC

Sonic Craft Sonicap

Super PP Capacitor

TRT Wonder DynamiCap

Vishay MKT 1822

Vishay MKP 1837 *

Vishay MKP 1839HQ 630VDC

Vishay Sprague 730P

Wima MKP4

Wima MKP10

Wima MKS4

* Personal favourites!

Amp Ohm FP-CA-AU 630VDC - 5% tolerance

Technical Specifications (according to manufacturer): "Amp Ohm Audio Capacitors are specially designed for high performance audio systems. The capacitors are hand wound and have their insulated copper leads hand soldered before being assembled in a plastic case and resin sealed. The resin filled end identifies the outer winding. This construction results in the capacitors having low ESR and low inductance and possessing high stability with respect to both temperature and frequency. They are ideal for use in loudspeaker crossover networks and valve amplifiers where pure sound is at a premium. Line on label denotes outer foil".

Sound: The Amp Ohm FP-CA-AU is a very neutral sounding capacitor that takes a nice smooth and calm approach to the reproduction of music. I found the balance of the midrange very pleasing letting acoustic instruments keep their natural warm tone. Absolute detail and air isn't quite up to the level of an Audyn Cap Plus or Mundorf Supreme but it comes very close although they do need some time to open up so don't judge them fresh out of the box. Spatiality is broad with reasonable depth but if you want "bowling alley" depth go for (the much more expensive) Mundorf Silver/Oil. Compared to the more luxurious Amp Ohm capacitors they are more 2D and a little rough, but again those cost far more.

Verdict: 8,5

Amp Ohm PF-XAL-AL 300VDC Paper in Oil aluminium foil - 10% tolerance

Technical Specifications (according to manufacturer): "Amp Ohm paper in oil (PIO) capacitors are hand wound using high aluminum foil. They are oil impregnated before being assembled and oil filled. The capacitors are then hermetically sealed in an aluminum housing with phenolic resin and rubber end discs. Each lead is hand solder sealed to the eyelets in the end discs. The leads are 1.0mm in diameter and made of tinned copper. All Amp Ohm Audio Capacitors are individually hand tested. Line on label denotes outer foil."

Sound: The Amp Ohm PF-XAL-AL 300VDC is very rich in harmonic textures and quite spatious. When fresh out of the box they can be a bit "chesty" or "nasal" sounding but they mellow out after quite some time of use (several hundred hours). Their tonal balance is very neutral and smooth, words like natural and analogue come to mind. Imaging depth is very good but not quite at the same level as their paper-in-wax or polyester-in-oil stable mates.

Verdict: 10,5

Amp Ohm PF-XAL-AL 630VDC Paper in Oil aluminium foil - 10% tolerance

Technical Specifications (according to manufacturer): "Amp Ohm paper in oil (PIO) capacitors are hand wound using high aluminum foil. They are oil impregnated before being assembled and oil filled. The capacitors are then hermetically sealed in an aluminum housing with phenolic resin and rubber end discs. Each lead is hand solder sealed to the eyelets in the end discs. The leads are 1.0mm in diameter and made of tinned copper. All Amp Ohm Audio Capacitors are individually hand tested. Line on label denotes outer foil."

Sound: The Amp Ohm PF-XAL-AL 630VDC is basically the same type as the above mentioned capacitor but with a higher voltage rating. The higher rating is obtained using thicker materials and therefore the 630VDC version (65mm) has a larger diameter than the 300VDC version (45mm). Both have the same length (95mm). The 630VDC version reminds me of a can of beer or coke. The higher VDC type is also very rich in harmonic textures and quite spatious. The tonal balance is very neutral and seems a fraction smoother than the lower VDC type. Imaging depth is very good but like the 300VDC version, not quite at the same level as their paper-in-wax or polyester-in-oil stable mates. My review notes also state: black background.

Verdict: 11-

Amp Ohm PF-XAL-W-AL 630VDC Paper in Wax aluminium foil - 10% tolerance

Technical Specifications (according to manufacturer): "Ampohm Audio Capacitors are specially designed for high performance audio systems, used in various applications. These paper in wax (PIW) capacitors are hand wound using high purity aluminium foil and have their 1.0mm diameter tinned copper leads hand solder sealed to the eyelets in the end discs. They are wax impregnated before being assembled and hermetically sealed in an aluminium housing with phenolic resin and rubber end discs, all being individually hand tested. Line on label denotes outer foil."

Sound: The Amp Ohm paper-in-wax alumnium foil type seems a fraction flatter or condensed sounding when in direct comparison to the Ampohm paper-in-oil alumnium foil type. It is a little more direct in it's presentation compared to paper-in-oil but more laid-back when compared to the polyester-in-oil types. I also noted less "fleshy" and a tad thinner than the Ampohm PIO. There also seems to be a fraction more emphasis on the frequency extremes giving it a miniscule loudness effect when compared to the very analogue midrange character of the polyester-in-wax type. This is not meant in a negative way seeing the overall high quality sound level of this capacitor, as it's character could prove usefull when fine-tuning a loudspeaker in a certain direction.

Verdict: 10

Amp Ohm FE-XAL-AL 630VDC Polyester in Oil aluminium foil - 10% tolerance

Technical Specifications (according to manufacturer): "Ampohm Audio Capacitors are specially designed for high performance audio systems. These polyester film capacitors are hand wound using high purity aluminium foil and have their leads hand soldered before being assembled and hermetically sealed in an aluminium housing with phenolic resin and rubber end discs.The 1.0mm diameter tinned copper lead out wires are solder sealed to the eyelets in the end discs This construction results in these components being ideally suited for use as coupling capacitors or as replacements for components in existing designs. Line on label denotes outer foil."

Sound: The Amp Ohm polyester-in-oil alumnium foil is overall very coherent and neutral. This type has a pleasent midrange-highlight when in direct comparison to the Ampohm paper-in-wax alumnium foil type. The polyester-in-oil is very rich and extremely good in retrieving ambient information such as room or hall acoustics. Music is presented in a natural and full-bodied manner. Compared to the Duelund VSF-Cu copper-foil the image is more "see through". Compared to the Mundorf Silver-Gold-Oil the presentation is richer, especially noticable on massed strings or large vocal works. On small jazz-trio's etc the Silver-Gold-Oil high-lights micro detail a little more but doesn't quite reach the same level of overall coherence the polyester-in-oil does so well.

Verdict: 11+

Ansar CPA polyproylene 450VDC - 5% tolerance (a.k.a. Ansar Supersound)

Technical specifications (according to manufacturer): "General purpose Audio grade component. Axial design. Ideal for all general audio usage, a wide range of voltages and values available. This range of components was designed mainly for the loudspeaker crossover manufacturers. The components are manufactured with the aim of producing a highly transparent component for use in critical signal paths such as the crossover network. They are an excellent all round product which have been designed to offer the best compromise between quality and cost. Highly regarded throughout the industry they are used by many of the UK's leading loudspeaker manufacturers."

Sound: The Ansar CPA has a vibrant, clean and clear nature that seems to be concentrated more on the top-end of the spectrum. Not completely neutral but therefore they can be usefull if you want to give a more open sound to a system that sounds a bit congested in the midrange and / or lower treble, in such a situation the Ansar CPA open's things up nicely. Used in a tonally neutral system they could do with a bit more presence and body, they tend to lean towards a slightly thin nature. This nature can make acoustic instruments like a grand piano or massed strings sound a bit distant. For example a Jantzen Audio Standard Z-Cap is more neutral and has more body weight but lacks the top-end "sparkle" the Ansar CPA produces. Nice thing though is that they never get harsh nor rough around the edges. Image depth is slightly flatter than higher grade capacitors but compared to other general purpose MKP's they perform very well. Top end detail is more prominant than the slightly rolled-off nature you find with a Clarity Cap SA. The Clarity Cap SA in return sounds more up-front in the lower treble range. They are nicely compact in size, so they can turn out handy when space is critical.

Verdict: 7,5

Arcotronics MKP-C4G 600VDC - 5% tolerance

Technical Specifications: Self-healing metallised polypropylene snubber capacitor intended for use in power semiconductor circuits to suppress or attenuate undesired voltage peaks e.g. electronic ballasts and motor applications.

Sound: The Arcotronics cap is a modest sounding capacitor, a little on the quiet side concerning dynamics. I quite like the midrange quality especially with percussion music. Drums, etc. had a nice natural timbre. There seems to be a focus on the midrange, the treble is slightly rolled off. Spatiality is a little compromised resulting in a slightly distant and compact image. Overall detail is slightly better than a standard Audyn Cap for example but doesn’t compete with an Amp Ohm or Mundorf Supreme. A good MKP for basic filter applications.

Verdict: 7

ASC X386S MKP in oil 600VDC – 10% tolerance

Technical Specifications: Industrial application capacitor. Although the tolerance stated is meant to be a poor +/- 10%, I measured all of them and they were all spot-on the stated capacitance. Now that is what I call built to industrial standards! I guess they state such a large tolerance because being designed for industrial applications they will be used in varying temperature conditions. The vegetable oil inside will therefore vary in fluency. But at normal room temperature they seem to be at their best. The values are different to the standard range but they come in values from 1,0 to 60uF although small quantities are hard to get unless you want to order more than a hundred of them. ASC also supplies these metallized polypropylene types to other notable High-End Audio companies, including Conrad-Johnson. ASC polypropylene and oil capacitors feature a sealed metal 'oil can' construction and hefty four-way solder/connector lugs on the bottom. The capacitor itself is made of metallized polypropylene film, similar in construction to standard MKP’s, but suspended in a bath of vegetable oil: some claim that this oil provides a damping effect in audio circuits. When you shake it you can hear the oil splash around!

Sound: They sound a bit dull at first because they take a while to burn-in. But after a few days of normal use they deliver a wide and open sound stage. Nice and neutral, maybe a slightly warm and lush sound. One of those things that don’t impress at first but sort of grow on you after a while, you learn to appreciate their qualities – great! If you want a lively and bright sounding filter then this is not your cap (try a Hovland Musicap instead), if you are looking for a smooth, warm and relaxed sound then give these a try.

Verdict: 7,8

Audience Auricap MKP 200VDC – 10% tolerance

Technical Specifications (according to manufacturer): "Auricap metalized Polypropylene capacitors are cylindrically wound with epoxy end fill and have very good volumetric efficiency. They are wound to exacting industry leading specifications to meet or exceed the requirements of MIL-C-55514A and MIL-STD-E method 103B. As with all metalized polypropylene film capacitors Auricaps are self healing. Failure mode is as an open circuit. Auricaps are made with the very best film available and are constructed to center value. Special care is taken to insure industry leading ESR values. Auricaps are designed to be a general purpose capacitor for use in all applications where size, value and temperature considerations are suitable. They are useful in signal coupling, filtering and power factor correction applications. The outside foil connection of Auricaps is identified with either a black lead (when leads are red and black) or a shorter lead when leads are solid core type. This identification is not a voltage polarity indication but is a consideration for minimum noise pick up.”

Sound: I find these capacitors to have a pleasently smooth and clear presentation that is slightly forward if directly compared to bright-ish capacitors like the Jantzen Silver Z-Cap or Silver Gold Z-Cap. The Auricap retrieve enough amibent information that helps to make an orchestra properly placed in a concert hall (recording permitting) and project the image more in the width than in the depth. Overall performance is very satisfactory and has something correct / complete about it. I have added them to my favourites list.

Verdict: 9

Audio Cap PPMF MKP 200VDC – 10% tolerance

Technical specifications (according to manufacturer): “The PPMF Audio Caps are metallized polypropylene, useful as upgrade from Mylar or inferior film caps, and available in values large enough to be ideal for speaker crossover networks. They are built of the best materials and exhibit excellent electrical and environmental characteristics. Their superior build quality and high capacitance values provide a high-quality stable, long-term performance not usually found in this price range. Thegold-plated OFHC leads provide long-term high reliability and excellent solder ability, superior to silver wire because of gold's non-oxidising properties.”

Sound: Slightly more detail, depth and separation than a standard Mundorf M-Cap but slightly less than a Hovland Musicap. The M-Cap has a more round character, the Audio Cap PPMF a more laid-back character. For the rest I find them reasonably neutral.

Verdict: 7

Audio Cap Theta PPT MKP-Sn 200VDC – 10% tolerance

Technical specifications (according to manufacturer): “The PPT Theta Audio Cap is an excellent film & foil capacitor for all audio circuits and power supplies. It provides low distortion performance and long-term reliability. It exhibits excellent electrical and environmental characteristics at a reasonable price. Its sonic signature is rich and full and its superior build quality ensures a high-quality stable, long-term performance not usually available in this price range. The gold-plated OFHC lead wires provide long-term high reliability and excellent solder ability, superior to silver wire owing to gold's non-oxidising properties.”

Sound: These caps have a lean, clinical brightness to them and at the same time lack transparency. A form of artificial clarity is created by means of a treble glare in the top end - at least they don't have a loudness effect. They work well in opening-up a dull, lifeless speaker but that's about it. Use them as a small value parallel to a large "dull sounding" cap only; they will clean up a cheap Intertechnik Audyn Cap nicely. But costing far more than an ERO MKP1837 I don't really see the point of buying them.

Verdict: 6,5

Axon True Cap 250VDC – 5% tolerance

Technical specifications: Low cost polypropylene capacitor very similar in physical appearance to SCR, Solen and Angela branded capacitors.

Sound: The Axon True Cap has a slight focus on the lower treble range giving it a fat and juicy character. They lack air and micro detailing, but what can you expect in this price range? They are not very subtle either but they never get harsh or over bright. Just your basic, standard quality MKP. It is rather like the Solen Chateauroux Fast cap but has a fraction more clarity so that is why it gets a higher rating. Nothing wrong with them but also nothing exciting. For example a WIMA MKP4 is more open, smoother and has better imaging.

Verdict: 6,5

Cicada Pure Aluminium Foil 100VDC - 3% tolerance

Technical specifications: Film and foil type MKP from Taiwan.

Sound: The Cicada Pure Aluminium Foil capacitor is similar in character to the Mundorf Supreme in that it has a slight top-end high-lighting except the Cicada lacks the fluidity and smoothness of the Mundorf. Compared to rich and harmonically natural capacitors like Jupiter BeesWax and the Obbligato Aluminium type, the Cicada Pure Aluminium Foil sounds a little rough and technical. After a very long burn-in time they did smooth a lot but they still maintained a sort of "hifi" sound. They are very accurate and good at retrieving detail. They put an emphasis on the leading edge of the note and have nice dynamic snap that can sound exciting on some recordings or types of music. But for me ultimately they could do with a bit more natural harmonic richness and fluidity to be able to shine in all situations.

Verdict: 9+

Cicada Pure Copper Foil 100VDC - 3% tolerance

Technical specifications: Film and foil type MKP from Taiwan.

Sound: The Cicada Pure Copper Foil capacitor is similar in character to the aluminium foil type except it is far more rich and fluid - bringing it closer to some other high-quality capacitors. Obviously it is the better of the two Cicada types. This richness and fluidity makes them more coherent and therefore the minor top-end emphasis is also less prominent making it easier for you to get into the music instead of listening to a good capacitor, if you know what I mean. The leading edge of the note and the nice dynamic snap are less detached, more in pace with the music.

Verdict: 10

Clarity Cap PWA MKP 160VDC - 5% tolerance

Technical specifications(according to manufacturer): “The PW range has long been established as an economical component producing improved sonic performance over many overseas brands. Over the years numerous companies have used this range as their entry-level products with great success. Available at ratings of 160Vdc, 250Vdc, 400Vdc and 630Vdc, it offers audio engineers the maximum flexibility when considering components for their circuits. Wound from 4µm, 6µm, 8µm and 10µm metallised film respectively, components can be selected using their slightly differing sonic performances and aspect ratios to give the optimum solution desired. Copper clad steel terminals are standard; however, others are available upon request Tape and resin colours are flexible with options shown in Custom products. Unless specified, capacitors would be supplied with white tape and red resin. ”

Sound: The Clarity Cap range has an overall similarity in tonal balance, going up the range you gain clarity and spatiality. I found the PW to be quite neutral with a slightly warmish presentation. Compared to the PX there is a loss of detail but they never sound dark. Compared to a standard Mundorf M-Cap the stereo-image is a little larger. The price/quality ratio is very good. I can recommend this capacitor if you have a tight budget and like a speaker to be as smooth as possible.

Verdict: 7

Clarity Cap APW MKP 160VDC – 5% tolerance

Technical specifications(according to manufacturer): “Available at ratings of 160Vdc, 250Vdc, 400Vdc and 630Vdc, it offers audio engineers the maximum flexibility when considering components for their circuits. Wound from 4µm, 6µm, 8µm and 10µm metallised film respectively, components can be selected using their slightly differing sonic performances and aspect ratios to give the optimum solution desired. Copper clad steel terminals are standard; however, others are available upon request Tape and resin colours are flexible with options shown in Custom products. Unless specified, capacitors would be supplied with white tape and red resin. ”

Sound: To be honest, I can't hear any difference between the Clarity Cap APW and PWA but that was to be expected, according to Clarity Cap they are the same. I found the APW also to be neutral with a slightly warmish presentation. Compared to the PX there is a loss of detail. The price/quality ratio is very good. I can recommend this capacitor if you are on a tight budget and are looking for a capacitor that doesn't stand-out too much.

Verdict: 7

Clarity Cap PX MKP 250VDC – 5% tolerance

Technical specifications (according to manufacturer): “The PX range was developed to address the performance gap between the PW and SA ranges. It is closer to the SA in terms of sonic performance but at a price very similar to the PW range. Since it was introduced, it has made significant inroads into the loudspeaker industry. Constructed from a 250Vdc(6µm) rated film, this component is spindle wound. It is then given a special heat treatment before it has insulated copper terminals hand soldered to give the best possible connection. The inherently low dissipation and dielectric absorption factors of polypropylene allied with excellent mechanical stability results in an extremely detailed sonic performance. The construction also results in a low self-inductance and ESR (Equivalent Series Resistance) and the devices are highly stable with regard to temperature and frequency. Tape and resin colours are flexible with options shown in Custom products. Unless specified, capacitors would be supplied with blue tape and blue resin.”

Sound: The Clarity Cap range has an overall similarity in tonal balance, going up the range you gain clarity and spatiality. I found the PX to be neutral with a slightly warmish presentation. Compared to a standard Mundorf M-Cap the stereo-image is a larger but less spacious than a Mundorf Supreme or Audyn Cap Plus. Clarity is a good step up from the PW and also the M-Cap. The price/quality ratio is very good. I can highly recommend this capacitor if you are looking for a nice, but not too expensive MKP.

Verdict: 7,5

Clarity Cap SA MKP 630VDC – 5% tolerance

Technical specifications (according to manufacturer): “The SA range, developed in conjunction with a renowned loudspeaker manufacturer, remains one of the most highly regarded axial components currently used in the audio market. Time and time again the component is specified as a benchmark for other manufacturers components to try to aspire to. Sales continue to grow year on year as new customers, in new markets appreciate its worth. Specially developed to meet the needs of the professional audio engineer in both hi-Fi and studio monitoring, these components are the result of extensive consultation between the audio industry and Clarity Cap. The capacitors are hand wound using a 10µm (630Vdc) rated polypropylene film. Following a special heat treatment cycle insulated copper terminals are hand-soldered to give the best possible connection. The inherently low dissipation and dielectric absorption factors of polypropylene allied with excellent mechanical stability results in an extremely detailed sonic performance. The construction also results in a low self-inductance and ESR and the devices are highly stable with regard to temperature and frequency.”

Sound: The Clarity Cap range has an overall similarity in tonal balance, going up the range you gain a bit in clarity and spatiality. I find the SA to be neutral with a slightly warmish presentation but also a bit closed-in. Compared to the Clarity Cap PX definition and separation are better, the stereo-image is also little larger. I did find the top end to be slightly rolled-off, not that they lacked detailed but on some recordings I wanted a fraction more transparency - but all in all still very nice. On the downside the "S" and "T" in vocals can be a bit plasticy, this is probably due to the lack in transparany in the top octave, making the octaves below sound a little masked. Making a capacitor using about 90% Clarity Cap SA and about 10% Mundorf Supreme works very well, this tends to open up the top end just nicely without altering anything else.

Verdict: 8

Clarity Cap ESA MKP 630VDC – 5% tolerance

Technical specifications (according to manufacturer): “The ESA range of components exploits the knowledge gained during the extensive research programme recently undertaken by Clarity Cap. The research programme looked into ways of reducing mechanical resonances inherent in a wound capacitor to hitherto unachievable levels. ESA capacitors are designed to offer a mid way house between the highly regarded SA range and the new no compromise MR range. Manufactured from polypropylene film the component is supplied in the familiar wrap and end seal style, wrapped in a polyester tape and encapsulated in an epoxy resin.”

Sound: Similar in overall character to the Clarity Cap SA but with more clarity and therefore a fraction more spatial. Like the SA they could still do with a bit more transparency but with a small capacitor placed parallel to the ESA this can be improved. The ESA also has a slightly warmish presentation and also benefits from making a total value using about 90% Clarity Cap ESA and about 10% Mundorf Supreme. This opens up the top end just nicely without altering anything else. Good overall qualities and an upgrade from the standard Clarity Cap SA.

Verdict: 8,5

Clarity Cap MR MKP 630VDC – 3% tolerance

Technical specifications (according to manufacturer): “The MR range of capacitors is the result of an extensive ground breaking two year research programme into audio grade capacitors. The resulting capacitor is, we believe, at the leading edge of today's high quality audio grade capacitors. The component is manufactured in such a way to substantially reduce the negative effects of resonance on sonic quality which is inherent in a wound component. This results in a sonic characteristic which is difficult to equal. Manufactured from metallised polypropylene film the component is housed in a coloured acrylic tube and encapsulated in an epoxy resin to assist in the overall sonic performance. ”

Sound: Like the Clarity Cap DTAC, the Clarity Cap MR doesn't have that dark character of the standard Clarity Caps and sounds in comparison very spatial and clear. Spatiality is one of the main strengths of this capacitor supported by very good separation of the individual instruments and vocals. The music is placed before a very quiet background with lots of detail making retrieval of ambient information like the natural reverberation of a concert hall easily distinguishable. Compared to a Mundorf Silver-Gold-Oil they are ultimately a little less transparent, presenting the information more up-front with a slight focus on the lower treble range. In comparsion the Mundorf SGO has a slight focus on the upper treble range.

Verdict: 11+

Clarity Cap DTAC MKP 630VDC – 5% tolerance

Technical specifications (according to manufacturer): “A narrow 10um (630Vdc) polypropylene film with a special spray and heat treatment contribute to the exceptional performance of this capacitor. These measures combined with hand soldered M8 male or female terminations ensure that the ESR is greatly improved when compared to the traditional axial leaded components. It has been designed to produce the lowest possible resistance within the component, which Clarity Cap believe has a direct relationship to sonic performance. The low ESR is particularly relevant in high quality crossover networks, ensuring that loudspeakers perform to their optimum. Tape and resin colours are flexible and unless specified, capacitors would be supplied with gold tape and black resin.”

Sound: The Clarity Cap range has an overall similarity in tonal balance except for the DTAC. It doesn't have the rounded character of the other Clarity Caps and sounds in comparison much cleaner. I may be exaggerating a little here, but the DTAC makes a Clarity Cap SA sound a bit cheap. Compared to a Mundorf Silver/Gold they still seem a fraction rounder and they are as transparent and clear as a Jantzen Audio Silver Z-Cap without being over bright. If you were looking for lots of depth, ambient information and concert-hall reverberation then I would advise to look at the Mundorf Silver/Gold, but if you prefer a slightly smoother top-end then the Clarity Cap DTAC is an interesting alternative.

Verdict: 10

Ducati 4.16.10 400VAC - 5% tolerance

Technical specifications (according to manufacturer): “The dielectric is polypropylene film, the electrodes consist of an extremely thin metal coating obtained by vacuum evaporation. Case and cover are made with self-extinguishing plastic material; the capacitive element is sealed with polyurethane resin. The main characteristics of these capacitors are: Low losses non-inductive winding; Self-healing property avoiding short circuits; Small size and limited weight; No leakage risk; Capacitance tolerance: ± 5%; Working frequency range: 50 ÷ 60 Hz; Individual test voltage: Between terminals: 2.15 Vn for 2 sec.; between terminals and case: 3KV for 2 sec; Dissipation factor tan δ: <20 10–4@ 20°C V=Vn, 50Hz; Protection Case and cover in self – extinguishing plastic material; Terminals: twin cable, unipolar leads; Protection degree: with terminals: IP00; with twin cable IP55; Threaded fixing bolt M8”

Sound: This industrial type capacitor (like the ASC and Inco) is quite nice! They sound a bit dull at first because they take a while to burn-in. But after a few days of normal use they deliver a reasonably wide and open sound stage. Nice and neutral, maybe a slightly warm sound. One of those things that don’t impress at first but sort of grow on you after a while, you learn to appreciate their qualities – great! Not the ultimate in sound staging or micro-detail and if you want a lively and bright sounding filter then this is not your cap. But if you are looking for a smooth, warm and relaxed sound then give these a try.

Verdict: 7,5

Duelund VSF-Cu Copper Capacitor 100VDC - 2% tolerance

Technical specifications (according to manufacturer): "The Virtual stack foil capacitor, a capacitor made specially for loudspeaker crossovers. This new capacitor is the realisation of a lifelong ambition. It consists of copper foil and high-density paper, soaked in pure mineral wax, coated with pure cocoon silk and finally, treated with special lacquers made from natural materials. It is without question a "green" product. The actual construction has been overseen by Mr. Steen Duelund Chief Engineer of Duelund Coherent Audio. Mr. Duelund has dictated the capacitor's special characteristics, i.e. its flatness, giving the opportunity to create its stack-foil working manner ensuring very low inductance, forming a solid block resulting in a form free of internal resonance. Furthermore, the flatness makes it easier to achieve greater values by connecting the capacitors in parallel".

Sound: I found the Duelund VSF-Cu to have a very natural timbre, smooth, clear, open, and at the same time they stay calm and controlled but delivering dynamics when the music calls for it. The tonal balance is near perfection, especially audible on well recorded acoustic instruments and the human voice. This makes my classical music collection so much more realistic. Also I was very pleased with the separation of every individual instrument in an orchestra, the string section is much more a group of individuals rather than just a group. In direct comparison to the Duelund I found the Mundorf Silver/Gold to be a little over-etched sometimes, they seem to have a slight top-end emphasis. The Duelund VSF-Cu in return has a slight top-end roll-off. Which would be best for you would depend on the rest of your system and personal taste.

Verdict: 12,5

Duelund CAST-Cu Copper / Paper-in-Oil Capacitor 100VDC - 2% tolerance

Technical specifications (according to manufacturer): "The Duelund CAST Capacitor is a no holds barred flagship capacitor. The construction builds on the foundation of the Virtual Stack Foil design but does so with the addition of a proprietary WPIO dielectricum which necessitates several days of impregnation under very high pressure. This creates a form with incredible damping properties giving a mechanical stability hitherto unheard of. On top of this casting process, a ring of hard pressed paper strengthens the damping properties of the design helping music flow effortlessly. The Duelund CAST capacitor is available for speaker use and as the CAST 630v for DC-applications".

Sound: The CAST capacitor has all the same characteristics as the VSF but with added top-end clarity and together with that, more spatiality. They are (like the VSF) super natural, smooth, clear and open. The tonal balance is extremely neutral, especially audible with good recordings of acoustic instruments and the human voice, so mainly with classical music. Like the VSF the separation of the individual instruments is very good and in an orchestra, the string section is a group of individuals rather than just a group. Soprano's have clarity without becoming hard to the ear, wind instruments (especailly the copper section) have that nice "metal" edge without becoming rough. Where in the past you had to choose between a Mundorf Silver/Gold/Oil (very good depth, imaging and top-end detail) or a Duelund VSF (extremely neutral presentation) you can now have the best of both worlds in the form of the Duelund CAST-Cu. I did find they needed quite a while to fully come to bloom, so give them a chance to burn-in.

Verdict: 14

Duelund RS Copper Loudspeaker Capacitor 100VDC - typical tolerance 2%

Technical specifications (according to manufacturer): "The all new RS series from Duelund is a further improvement on the VSF line of capacitors. After many years of research and development Duelund decided to improve upon the original VSF by applying the elaborate manufacturing process used in making the CAST version. Using high purity copper foil with a wax impregnated dielectric and treating it with the anti-resonance CAST material the RS series was born. These capacitors approach the CAST performance in a number of ways, but at a lower cost. The outer lead out, closest to the edge of the capacitor, is connected to the outer foil and as such should be connected to the lowest impedance path to ground".

Sound: After many hours of burn-in time the main thing that I kept writing about in my notes was how natural the Duelund RS-Cu sounds. This is one of the few capacitors with which I didn't have the urge to do some fine-tuning or mixing with other types / brands to reach an optimum result. In all the loudspeaker crossovers I tested them in, they just sounded so logical everytime. It didn't seem to matter if the tweater had a textile, magnesium, ceramic or beryllium dome - the Duelund RS just portrayed the sonic signature of the tweeter as it was. Nothing added, nothing hidden, no need to tweak, a real no brainer. Comparing the Duelund RS to the Rike Audio S-Cap I found the RS to give a richer tonal balance, like most copper versus aluminium caps do. The Rike Audio S-Cap seemed more up-front and a little more forward in the lower treble. In direct comparison the Duelund RS had more depth and was a fraction more forgiving to the ear. Not that the S-Cap is rough, not at all, but the RS just seemed to "flow" a little more. Focussing on the highest frequencies, again the Duelund RS seemed to sound the most natural. Various high-grade Mundorf capacitors that I compared the RS to all seemed to high-light that area a bit. This can be usefull or pleasent in some cases, but for me, they were not strictly neutral. Compared to the Duelund VCF-Cu the top-end has improved. Although a very nice capacitor, I always found the VSF-Cu to have a slightly rolled-off top-end. The Duelund RS, like the CAST-Cu, has more top-end clarity and together with that, more spatiality. Are we then looking at a CAST-Cu in disguise? No, the CAST-Cu still is the no-compromise capacitor with a blacker back-ground, making it more silent than the RS. Also the RS-Cu doesn't quite have the same image depth as the CAST-Cu. But like I stated earlier, the Duelund RS Copper Capacitor is a real no brainer, once you have put this capacitor in your loudspeaker crossovers you will never need to tweak again! Everything just sounds so logical.

Verdict: 13

Epcos B32523-Q3475-K26 MKT 250VDC - 10% tolerance

Technical specifications (according to manufacturer): "Metallized polyester film capacitors (MKT) B32520 ... B32529 General purpose (stacked/wound). Typical applications: blocking, coupling, decoupling, bypassing RFI for automotive; Max. operating temperature: 125°C; Dielectric: polyethylene terephthalate (polyester, PET); Stacked-film technology for lead spacing 5 to 15 mm = code C, D or E in digit 7 of ordering code; Wound capacitor technology for lead spacing 10 to 27.5 mm = code N, Q or R in digit 7 of ordering code; Plastic case (UL 94 V-0); Epoxy resin sealing (UL 94 V-0); Features: High pulse strength, High contact reliability; Terminals: parallel wire leads, lead-free tinned, special lead lengths available on request."

Sound: Suprisingly good sounding polyester type. For tonal balance I actually prefer them to the Epcos B32656 MKP type. Not quite as coherent as the Vishay MKT1822 but still pleasent. I can imagine them to work well in woofer impedance correction networks, where as the Vishay MKT1822 actually works well in the direct signal path.

Verdict: 6

Epcos B32656-A6475-J MKP 750VDC - 5% tolerance

Technical specifications (according to manufacturer): "Metallized polypropylene film capacitors (MKP) B32651 ... B32656 High pulse (wound). Typical applications: electronic ballasts, switch-mode power supplies; Max. operating temperature: 110°C: Dielectric: polypropylene (PP); Wound capacitor technology with internal series connection for VR ł1250 V DC; Plastic case (UL 94 V-0); Epoxy resin sealing; High pulse strength, high contact reliability; Terminals: parallel wire leads, lead-free tinned; Special lead lengths available on request."

Sound: Sounds kind of "plastic" with a rather 2D, flat image. Midrange is snappy and there is some pleasent treble bite that brings them just above basic quality polypropylene types. Fine for parallel sections in woofer and midrange sections of a loudspeaker crossover, but personally I would not use them in the direct signal path of a tweeter.

Verdict: 7

Epcos B32774-D1505-K MKP 1300VDC - 10% tolerance

Technical specifications (according to manufacturer): "Metallized polypropylene film capacitors (MKP) B32774 ... B32778 MKP DC link; High density series; Typical applications for compact design of: Frequency converters, Industrial and high-end power supplies, Solar inverters; Max. operating temperature: 105°C (case); Dielectric: polypropylene (MKP); Plastic case (UL 94 V-0); Epoxy resin sealing (UL 94 V-0); Capacitance values up to 110uF; Excellent self-healing properties; Overvoltage capability; Low losses with high current capability; High reliability; Long useful life; Terminals: parallel wire leads, lead-free tinned."

Sound: Similar in looks and sound to the Evox-Rifa PHE 426. Snappy and dynamic but rather up-front and forward in the midrange. The top-end treble has a slight glaze over it (not quite as strong as the Evox-Rifa) and therefore lacks a bit of sparkle and transparancy. Less of a "plastic" taste to it than the Epcos B32656-A6475-J. Fine for parallel sections in woofer and midrange sections of a loudspeaker crossover, but personally I would not use them in the direct signal path of a tweeter.

Verdict: 7+

Erse Pulse-X MKP 630VDC - 5% tolerance

Specifications (according to manufacturer): "ERSE’s Pulse X caps are a premium audiophile grade capacitor designed for quick transient response and ultimate musical performance. Every attention to detail was put into the PulseX capacitor line to insure premium performance. A premium grade of “defect free” aluminum metallized polypropylene film was chosen from an industry leading film supplier. Specially designed German winding machines with tension feedback control allow for precision repeatability during manufacturing. This industry first technique allows us to virtually eliminate mircrophonics and obtain a tight ± 3% tolerance, with virtually no scrap. All leads are lead free (RoHS Compliant), oxygen free 99.99% pure copper. Each lead is attached to the body of the capacitor with ultrasonic welding. To further reduce equivalent series resistance and improve long term reliability, the leads are then soldered with lead free silver solder. PulseX caps are then wrapped in flame proof polyester tape and the ends are epoxy filled. Before final packing, each PulseX cap is tested with certified premium quality Wayne Kerr capacitance bridges to insure a ±3% tolerance centered on the nominal value. The PulseX caps display signs of a near perfect capacitor. Total harmonic and IMD distortion and phase distortion are virtually immeasurable, while all losses are near zero in every aspect. PulseX caps will allow your music to be accurate and uncolored in every way."

Sound: Compared to the Transient-X from the same brand, the Pulse-X sounds rather dull and 2D. The treble is produced in a slightly "mushy" manor. This is fine when used in parallel sections and as a less critical midrange series capacitor but if you are looking for something in the tweeter's direct signal path, go for the Transient-X that is far more open, dynamic and has less background noise. Things like massed baroque choir become a mess, the Erse Pulse-X doesn't seem to keep a clear overview when the programme material gets complex. But the Transient-X is in another price-range, so not a fiar comparison. The Pulse-X basically is in the same league as capacitors like the Axon True Cap, Intertechnik Audyn Cap QS, Jantzen Audio Cross Cap, SCR Châteauroux MKP-PB, Solen Fast Cap PB-MKP-FC, etc. It's a fine overall standard quality capacitor for use when your budget is very tight.

Verdict: 6,5

Erse Transient-X MKP 1200VDC - 3% tolerance

Specifications (according to manufacturer):

Sound: The Erse Transient-X has lots of "in your face" detail without getting aggresive, it does a good balancing act in hearing enough detail but not too much. These capacitors are very usefull if you need to add some clarity to your system. They seem to do well in improving stick definition on the ride cymbal of a drum-set, like going from a hickory 5A to a 7A stick size. They also bring out the leading edge of a guitar nicely. The character of the Erse Transient-X is less well suited for classical music, it lacks some harmonic coherence at the top end, most noticable on un-processed acoustic music. So summing things up: they are very good in clearing up a dull system but only if you don't listen to classical music ;-)

Verdict: 9,5

Evox-Rifa PHE 426 MKP 250VDC – 5% tolerance

Technical specifications: “Single metallized polypropylene film pulse capacitor. Pulse operation in SMPS, TV, monitor, electrical ballast and other high frequency applications demanding stable operation. Polypropylene film capacitor with vacuum evaporated aluminium electrodes. Radial leads of tinned wire are electrically welded to the contact metal layer on the ends of the capacitor winding. Encapsulation in self-extinguishing material meeting the requirements of UL 94V-0. Two different winding constructions are used, depending on voltage and lead spacing”.

Sound: Similar to the Evox-Rifa PHE 450, the PHE 426 is transparent and clear sounding but less grainy. The treble still has a slight glaze over it, but it can be removed by putting a 0,01uF Vishay MKP1837 parallel to it. Imaging is quite good with a nice sized sound stage but only average separation. Dynamics are nice and snappy and the treble is well detailed. Similar in character to the Obbligato aluminium dry type, only it misses the analogue feeling to it. Compared to a Mundorf RXF it is a little brighter. This capacitor has a high price/quality ratio and matching it with other capacitors to create a custom capacitor gives very good results.

Verdict: 7+

Evox-Rifa PHE 450 MKP 250VDC – 5% tolerance

Technical specifications: Double metallized polypropylene film pulse capacitor intended for high frequency, high current stress applications. Typical Application: Protection circuit in SMPS and Electronic Ballasts. Encapsulated in self-extinguishing material meeting the requirements of UL94V-0. Only available in values up to 4,7uF.

Sound: The Evox-Rifa PHE 450 is a very transparent and clear sounding capacitor, some times a little too “fresh” sounding but this character can be compensated by adding a capacitor with a more round character – I had very good results with about 10% of the total value made up from Angela (Jensen) paper in oil. On its own I find the midrange a little under exposed and the treble has a slight glaze over it, which again can be removed by putting a 0,01uF Vishay MKP1837 parallel to it. Imaging is quite good with a nice sized sound stage but only average separation. Dynamics are nice and snappy and the treble is well detailed. It might seem that I am not too keen on the PHE 450 but this is just a way of trying to describe its character in words – I still find it a very nice little capacitor considering the price. This capacitor has a high price/quality ratio and matching it with other capacitors to create a custom capacitor gives very good results.

Verdict: 7

Evox-Rifa SMR 63VDC – 10% tolerance

Technical specifications: “ Metallized polyphenylene sulphide. Construction: polyphenylene sulphide film capacitor with vacuum-evaporated aluminium electrodes. Radial leads of tinned wire are electrically welded to the contact metal layer on the ends of the capacitor winding. Encapsulation in self-extinguishing material meeting the requirements of UL 94V-0. Typical applications: automotive and other applications with high ambient temperatures; applications requiring high stability and low losses; offers excellent sound quality in audio applications.”

Sound: Very compact little capacitor that sounds slightly on the bright side of neutrality. It is clearer than a Clarity Cap APW or PWA for example and has a reasonably wide image but lacks depth. So the sound stage is good i