A Tale of 2 Caps

A take on Audio Note vs Jensen coupling capacitors


At 09:53 AM 10/15/02, you wrote:
>Hi BS,
> Hope you could write something about your experience with the
> Jensen vs Audio Note coupling cap?
> A 2 line will do. Want to do a customer feedback page.
> Let me know if you mind having your name/e-mail add there. Thanks.

2 line? Don't think this is going to give a convincing picture of the
potential of the caps.
Here it goes,

Ever since I rekindled my quest of high fidelity beginning of last year, I wanted to distance and not involve myself with tube amplification, as there were vast variables in the aspect of theory and practice. There were too few amplifier brands to choose from and even if there were, prices were outrageous. Third party parts and tubes are not easy to come by and available mostly from abroad. NOS tubes and associated parts are constantly overrated at auction sites and online stores.

On the other hand, solid-state amps are plentiful, having loads to choose from depending on one's budget. I picked up a used top of the range Audiolab system separates and a pair of Dynaudio Contour as my ultimate music system. At that point of time, my firm intention was the system would suffice for many more years in the future and spend my valuable money on good software.

Having joined KLANS and to interact myself with very nice people, having fruitful and constructive conversation and auditioning excellent systems in their home. The topic of tube amplification and its possibilities started to work my imagination. I was very amazed that some members swear by having tube amplification and had spent huge effort tweaking, modding and various upgrades to achieve their objective. Some members and friends have highly collectible equipment and with the right ingredients in the amplification chain, produced sound that could equal or put much expensive gear to shame.

One thing led to another and I finally allowed myself the opportunity to implement the ideas that I had learnt, absorbed, and evaluated over a period of time. I set my sights on building a simple 12-Watt push-pull tube amplifier based on a classic Mullard circuit. I started off with readily available carbon resistors, caps and reasonably priced tubes. The initial cost of the project, after some evaluation would not be an issue. The circuitry was simple enough and took some days to put together. It now became very apparent that a DIY tube amp is far less fussy, much simpler in design and cheaper to build.

As time progressed and reliability assured, I felt that the amps were ready to deserve quality components. I went about purchasing better components from RS, Farnell and some online hobby stores. I also acquired some reasonably priced tubes from individual sellers on the Internet.

Having the required components at hand, the amps were frequently exchanging places from my living room and kitchen countertop. The easiest idea to implement was a direct replacement of the signal capacitors. I started to experiment with Solen MKP, Auricaps, and a handful of vintage Paper-In-Oil caps. Each of the capacitors resulted in a different character and having merits in a different area. Nevertheless, it was a hugely noticeable improvement over the initial cheap capacitor. Having met up with Yeo of diyparadise.com proved a valuable encounter and friendship. He has great knowledge of tube components, and retails desirable items for an attractive price coupled with very prompt delivery. Thumbs UP!

Very recently I was allowed the golden opportunity to compare and test-drive premium Copper Foil signal capacitors from Jensen and Audio Note.

The Jensen Copper PIO are very well constructed. These are currently premium Jensen signal capacitors. Standard silver coated leads, aluminum tube and insulated in an insulated clear shrink plastic sleeve. The signal caps are rated at 600 Volts. It's interesting to note that the price difference between 0.1uF and 0.22uF are almost similar but the former looks a lot more smaller and cheaper than it's bigger brother. The 0.22uF looks a lot more handsome for the price. In the past, Audio Note signal capacitors were re-badged Jensen signal capacitors and supposedly identical in construction and sound quality. Not anymore! Audio Note now makes their own and to their specifications.

The premium Audio Note Copper PIO caps are encased in a solid 2mm bare copper tube contributing to the substantial gross weight of the capacitor with silver coated leads. Boy! This is HEAVY! It's also rated at 600 Volts. The exterior of copper tube looks shiny when new but will tarnish over time. There's no insulation material over the copper tube. There is some resemblance to a shotgun bullet. On the lighter side, I wonder if spent shotgun shells could be used to construct new signal capacitors.

Audio Note also have silver foil PIO capacitors but I shall not discuss it. These are obscenely priced and not available just anywhere. I'm told that the Audio Note Copper Foil capacitors are frequently a sell out. The Audio Note capacitors were fitted in place of the well run-in resident Jensen. I had them there for more than a week. It's highly recommended that both capacitors be allowed to burn-in at least hundred hours for it to exhibit it's true potential quality.

At initial use, the Jensen seems unimpressive. The vocals and music appear tame although there are faint suggestions of good detail and resolution to come. One gets the impression that every compact disc recording was mastered from an analog tape. As time progressed, the sound gradually open out in increments. Come one fine day, it's true potential is realized.

The Audio Note caps sounded rather dreadful, shrieky, a little too sharp and grainy in some areas. I would wait and evaluate at a much later date.

It's a whole lot a new and different picture after the recommended run-in period.

Audio Note capacitors exhibit exciting speed and stunning clarity like with having fast caps or no caps at all. Sparkling resolution, detail and coherence, making the amp really sing, is where the Audio Note out performs every other type of plastic caps I've experimented. There is small amount of emphasis in the mid-highs and the upper registers. One could also translate this effect as a tinge of tonal brightness, nevertheless it makes the music warm and inviting. Imaging and focus is excellent. On the lesser quality, there seems to be less air around the music, a touch drier or sterile but the experience of greater excellent dynamics can override these little deficiencies.

Bass lines are impressive, tight, clean and with sufficient authority. Bass response can go down as low as the amp can offer. Sound staging is wide, open and sufficiently deep in depth. Good recordings appear to have good holographic qualities, which makes the image more convincing. All the essential elements contributing to a classy sound is brought to your immediate attention. Once this little gremlin is installed, there's no turning back to plastic signal caps.

I sense a more modern sound with greater speed and less decay in my tube amp. I have the opinion that the speed, pace and timing is largely similar to high quality polypropylene caps or direct coupling topology, but handling with a great deal more finesse. The dynamics are generous and tightly controlled. Vocals are brought forward to the right degree accompanied with good layering. Musical sweetness is not quite apparent as this may be due to other components suppressing this quality.

Having the Audio Note caps fitted could cause some loss of vintage sound quality but makes up with all the mentioned qualities which can make an amplifier sing with gutsy display, involving with an ambience way beyond the stock version fitted with plastic caps. Audio Note capacitor fitted amps would do very nicely when fed with up-beat music, fast numbers and orchestral classics. You'll never have a chance to yawn, but sit-up, listen and enjoy the music.

In comparison to the Audio Note caps, I strongly feel the Jensen still has better compatibility to a wider range of music. The overall musicality, balance, timing, coherence and a more relaxed tone would suit my personal preference. Musical instruments like strings, acoustic guitar, cymbals and high pitch percussion have a wonderful tone, displaying sweetness and delicacy which is never realized in plastic caps.

Jensen also contribute to an exciting display of lush, airy music and one gets to hear the scale of a wide soundstage in orchestral classics. I must add that the other qualities of resolution, clarity and detail are nothing short of exemplary. Vocals are similarly brought forward to the right degree without any undue harshness, grain or over emphasis. It's smooth, sufficiently live and vibrant. I'm extremely pleased with the excellent timing and pace that is achieved with vocals and uncomplicated music. It's neither too fast nor too slow, I find it just at the right amount in my amplifier. The overall tone is even and accurate as can be. Since my speakers are quite uncolored and largely neutral, I get the impression of a very honest sound. I could enjoy the music for many hours without undue fatigue. I'm full of praise for the Jensen.

Between the Audio Note and the Jensen, there's very little or nothing to grumble about and much praise is due to each of the candidates.

The merit of each one in a different area of the sound spectrum makes the difference in character. One can't possibly have everything in one brand of capacitor. Choice of either is subjective and very personal. There are still many who still firmly believe the use of high quality polypropylene caps to produce excellent results. Prices would also be a deciding factor.

In my opinion, an original or stock vintage amp cannot fully deliver the resolution, dynamics, and detail that the compact disc can offer. Some may disagree to my statement but I beg to differ on this fact. Stock vintage amps that may have undetected defective or unreliable parts, beyond operating tolerances can contribute to a load of undesirable sound qualities, unreliability, and under-par performance. It's a fact that no vintage tube amp components last forever. Internal components, tubes included, have to be replaced in due time to prolong the lifespan and performance.

I'm confident many could agree with me that when the time comes for repair or parts replacement, consider the use of audiophile quality components as far as one's budget could stretch. Many vintage resistors and caps easily drift beyond operating tolerances and one can be considered extremely lucky if those survived till today. Vintage resistors and capacitors are incomparable to current day components. They are vastly superior, with tighter tolerances, and highly reliable.

In another twist, my amplifiers are now fully settled with 8 pieces of Jensen copper-in-foil PIO capacitors, synergizing with the latest Holco H4P 1 Watt resistors rated at 0.5% tolerance. The other assorted components consist of some premium silicon coated and ceramic wire-wound resistors from Welwyn UK, an affordable Blue ALPS 100K pot. Assorted tubes from JJ/Tesla, Mullard, Philips JAN and GE are pressed into service.

The Audio Note caps have crossed over to permanently reside in a commercially branded 300B amplifier. Along with the recent Holco resistor upgrade, the differences were not subtle but HUGE gains. Along with all the good qualities I had found with the capacitors made the 300B amp sound nothing short of even more glorious and stunning. More detail, resolution, clarity, imaging, tonal timbre, and accuracy are immediately realized. The amp is extremely well behaved and has the capability of revealing faults in bad recordings. The owner has expressed that he's heard some detail not apparent before the resistor upgrade. The amp now handles delicate passages with more finesse and with a lower noise floor. There's a wonderful glow to the instruments and very appealing vocal tone that satisfied me and the owner to the fullest extent. Bass lines are further controlled and tightened up much more than before the resistor change. A possibility of achieving further improvement is tube rolling, earlier done by the owner. One never gets the confidence that this is no ordinary 300B amplifier. There were a few more tweaks and other vital components replaced but that's a trade secret.

Matched with an excellent source, speakers and fed with good music, I dare say it would give a real Audio Note 300B or something similar in that realm a good run for it's money.

It's highly unlikely that many manufacturers would use Audio Note and Jensen signal caps in their implementation, simply of high cost, save Audio Note themselves. It's possible that some would specify these capacitors as part of their component upgrade offers. From experience, many commercially available stock tube amps have standard polypropylene signal caps no better than SOLEN MKP does. I wish to state that SOLEN MKP wasn't a bad performer at all. I cannot complain much considering the very affordable price. However, it does lack much finesse and sonic quality a PIO cap would have.

The Audio Note would be an excellent replacement or upgrade to newer or present generation of tube gear. Both these audiophile capacitors retail at approximately US$25 a pop excluding shipping. It's not exactly a cheap upgrade but I personally feel that the returns could prove tremendous. I would highly recommend the Jensen as a first choice alternative replacement for defective or leaky signal caps in 50- 60's vintage amps to sustain the vintage sound quality. In closing, If one is very particular, one should experiment to obtain the desired result. What works well in my system may not work well in yours.


BS Lee

Thanks for your input!