It’s been a long since I promised to write this article: A comparison between Audio Note Copper Foil Mylar-in-Oil, Jensen Copper Foil Paper Tube, and Jensen Copper Foil Copper Tube. Some of my blog readers already email-ed me to ask about this. Due to my main job, I couldn’t finish this article immediately. So just this weekend, I spend few hours to have a listening session on this three capacitors.

Below is the test bed. A little bit awkward, but at least it works flawlessly!

I always do such comparison test in real time. I want to make sure I could snap between capacitor in very short time, without too many delay. This to prevent “memory lost” of the sound of each capacitor.

My best choice is ELMA Selector, 2 poles, 6 positions. I could test up to 6 capacitors on the same time, just switch the button to select which capacitor that I want to hear.

Here is the contenders. All of them were actually “in-oil” type capacitors. Audio Note switches to Mylar based instead of Paper. According to them, the Mylar will give better durability instead of Paper. Their old Paper-in-Oil design has some reliability problem, thus they prefer to change the design. Jensen still loves the Paper, so both of the capacitors actually Paper-in-Oil design, with Copper Foil. Just different on the chassis, one is Paper, the other is Copper. Copper case makes the capacitor even heavier than the Paper tube. Does it make different? We will see (I mean, hear).

Ok we shall start the listening session. I pick some tracks from Norah Jones (Come Away with Me), Chen Lily LPCD45 (我和你), Ingram Washington (My Funny Valentine), Eriko Ishihara (I’ve Got You Under My Skin), Ingebjorg Bratland (Mitt Hjerte Alltid Vanker), and Livingston Taylor (Isn’t She Lovely).

Due to limited time, I can’t write down my impression on each track, so I will give overall conclusion of each capacitor.

This new Audio Note Copper Foil Mylar-in-Oil has better high frequency resolution compared to the old one (Audio Note Copper Foil Paper-in-Oil type), but it’s just still not too “open” enough. The vocal is sweet, “swing and slow”, with good resolution. Staging is just enough, not too deep, but it’s quite well separated between the front, middle, and back side layer. At this price point (around US$ 55 each for 0.47 uF), I would say the performance is good to excellent. Good for overall performance, excellent if you do really like mid/vocal and not playing a lot of complex high frequency. I’m thinking a full-range driver performance to visualize the Audio Note capacitor sounds like (vs multi-way driver speaker). I would say, it’s your call to love or not to love this capacitor.

The Jensen Copper Foil Paper Tube was my favorite (before). I have used this capacitor for quite long time to replace the old Jensen Copper Foil Aluminum Tube. With price tag around US$ 100 each (0.47 uF), it’s actually quite serious capacitor on the market. We go straight to the sonic performance. It has good midrange, but with better high frequency extension compared to the Audio Note, maybe around 20-30% better in terms of high frequency, while maintaining the sweet vocal (just “enough” sweet). But still, for a very complex music with a lot of high frequency resolution instruments (we are talking about LP with live music genre), I think this capacitor is still not good enough (caveat: this is from my side, an owner of Duelund CAST Ag).

Finally, we come to the latest contender, the Jensen Copper Foil Copper Tube. The different between this capacitor and the previous one actually only on the case material. This one uses pure copper case instead of paper. Well, it’s quite easy to oxidize (same like the Audio Note), so be careful and pay extra care when handling this kind of capacitor. Compared to the Paper Tube, the Copper Tube provides even better high frequency extension. Surprisingly, the different is quite significant. If you are listening back to the Paper Tube, you will hear as if there is an extra layer between the singer and you. With the Copper Tube, the layer is removed. Clear vocal, better staging. But at some point of male vocal, it loses its weight, but not really significant. On the other side, with female vocal, I feel crispier vocal and slightly better resolution. You have to pay 10-20% more expensive for this Copper Tube compared to Paper Tube. Does it worth the upgrade? If you are listening mostly classic, rock, live, or any other kind of music which needs extra high frequency resolution, it’s definitely a nice to have one.

Brief conclusion:

  • Audio Note comes back with its new Mylar-in-Oil design. Should have better reliability because of its new design and also have better high frequency extension. But I think Audio Note still emphasizes on the midrange band, as if we are talking a full range speaker here. It’s your call, not a matter of right or wrong. At US$ 55 each for 0.47 uF, the price is quite a bargain.
  • Jensen maintains the old Paper-in-Oil design, but they are offering 4 type of chassis (Aluminum, Paper, Copper, and Ceramic). The overall vocal is quite sweet, but with added dynamic and high frequency extension. Surprisingly, the Copper Tube provides significant improvement. The Copper Tube has even better high frequency, separation, and resolution, although with a small trade-off on the midrange side. While the Paper Tube could be an all-round solution, sweet vocal, but with extra high frequency compared with the Audio Note.
  • As comparison, I would prefer Copper Tube on 300B, Paper Tube on EL34, and Audio Note on KT88 Push Pull or perhaps 2A3.
  • Sorry if my review sounds that I don’t really like all those three capacitors above. They are very good to excellent capacitors, really! But since my daily life is with the Duelund CAST Ag, so it’s very hard for me to get back. I’d try to be as objective as I can, but still I miss something when listening those three capacitors. If I should score the Duelund CAST Ag at 10, all of three above will get between 7.5 to 8. It’s quite good, right? Since the price different between Duelund CAST Ag and those three capacitors also very huge. Audio Note costs about US$ 55 each, Jensen around US$ 100-120 each (all 0.47 uF). The Duelund CAST Ag could cost over US$ 600 each! At fraction of cost, definitely those reviewed capacitors above have performed excellent sonic performance for most of my daily usage (the Duelund definitely not 5-10 times better as the price separates them).

VS Duelund CAST Ag:
Shortly after finished the comparison, I soldered back my Duelund CAST Ag (my current reference, priced around US$ 1500 /pair 1 uF). Well surely this capacitor is at different level with the previous three (again at 5-10 times price different). The high resolution is there, the vocal maintains its sweetness, staging is superb. All in perfectly harmony. I would say its musicality and microdetail are what we are talking about. All the tones seemed so balanced, well controlled, and proportional. This is the first capacitor which I could listen the Classic, Vocal, Jazz, or Pop, without afraid of losing their balance. Well, you got what you’ve paid though 😉