The Duelund CAST Tinned-Copper Capacitors
I know a lot of you out there consider the line of Duelund CAST capacitors to be the world's finest capacitors, as do I, and true to form, I think the new Duelund CAST tinned-copper capacitors are world beaters as well.
Personally, I think capacitor history is being made right now by what Frederik and Duelund Coherent Audio are doing with these CAST tinned-copper capacitors, they're that good.
What Frederik has accomplished for advancing the audio arts in creating the Duelund tinned-copper capacitors is truly remarkable, as they are simply amazing in their tremendous music-making ability, as I shall describe more fully a little further along in this article.
The new Duelund CAST tinned-copper capacitors are made exactly the same way as the pure copper foil or pure silver foil Duelund CAST capacitors are, except that they use tinned-copper foils instead.
One of the 18uF Duelund CAST tinned-copper capacitors used in the project is shown in the photo below.
The Duelund CAST capacitors represent the ultimate expression of Mr. Steen Aa. Duelund's thirty-five years of research into perfecting capacitor design for audio use, and as Frederik has said, "The legacy of Mr. Duelund is to never accept compromise, and that is a principle we proudly uphold in the Duelund CAST capacitors."
Frederik told me that many capacitors today use an insulating plastic film as the dielectric because it makes them inexpensive to produce, but the problem with using plastic is that it noticeably degrades the audio signal, "With plastic you get what Steen would describe as an echo, masking the real details of the signal."
So, in the Duelund CAST tinned-copper capacitors, like the pure copper and silver foil Duelund CAST capacitors, Frederik doesn't use any plastic, but rather only annealed tinned-copper foil in natural paper and oil, along with resonance control both inside and outside the capacitor.
A capacitor is made using two foils with paper between the foils, which results in capacitance being created in the electric field between them.
Each Duelund CAST tinned-copper capacitor is completely hand crafted in an incredibly labor-intensive process:
"Foils of tinned-copper are initially wound with paper to a certain value that is a good deal over the needed capacitance. Then the foil is put under vacuum pressure in an oil tank at high temperature for about a week, so that everything inside the winding undergoes vacuum impregnation and is permeated by oil."
"When this process is done, the resulting foil is wound by hand in a humidity and temperature-controlled room to an exact specification, and then it is placed back into the oil."
"Immediately after this process the winding is sealed by the use of a special lacquer, which is also used in the yacht industry to seal against moisture. This takes another week. During this process a ring of vacuum impregnated paper has been readied with a base of our CAST material."
"The winding is heated and then placed in the ring & base assembly and CAST material is poured on top of it in five stages, with air bubbles in the CAST material being forced out by applying a very precisely controlled flame to the surface (yes really!). This process takes another week. Following this step, the capacitor is measured and checked (as it has been at every step along the way), and if everything is ok, then we ship it to the customer. The total production time is typically six to eight weeks."
Other than their obvious high quality, one of the most striking aspects of the Duelund CAST tinned-copper capacitors are their large size and heavy weight, which is due to their perfectionist design using natural materials and tinned-copper foil—they simply have to be larger than mass produced capacitors using this approach.
Frederik says the careful selection of materials and the Duelund no-holds-barred style of design provides dramatic benefits for audio applications:
"From a performance standpoint, the main thing is an absolute lack of coloration, and a much more natural presentation—things don't float around but stay locked in time and space. How you perceive and understand the layers in the music becomes greatly enhanced, primarily because of the sudden silence in between notes. Micro and macro dynamics take on a whole new meaning. Mr. Duelund would liken it to drinking Coke your entire life and then suddenly having a drink of pure water."
As mentioned earlier, for the Duelund-Altec Project we used the new Duelund CAST tinned-copper capacitors in positions C1 (18uF), C2 (10uF), and C3 (0.82uF) of the crossovers for the vintage "Stokowski" Altec's, using a Jean Hiraga inspired crossover circuit originally developed for the professional line of Altec A5 (or A7) Voice of the Theater loudspeakers with 16 Ohm drivers to optimize their performance for home use (see the schematic below).
Duelund CAST Tinned-Copper 18uF capacitors for C1
I photographed the 18uF Duelund CAST tinned-copper capacitors from a few different angles so you could get a better idea of what they look like, and to give you a better idea of their size I've shown the Duelund CAST tinned-copper capacitors with an 8-ounce coffee cup for a size comparator (below).
Each Duelund CAST tinned-copper 18uF capacitor is 7 1/4 inches across (18.42cm), 2 inches tall (5.1cm), and weighs 2478 grams (5.47 pounds).
All of the Duelund CAST tinned-copper capacitors used the Duelund DCA16GA tinned-copper wire for leads.
Duelund CAST Tinned-Copper 10uF capacitors for C2
I also photographed the 10uF Duelund CAST tinned-copper capacitors from a few different angles so you could get a better idea of what they look like, and to give you a better idea of their size I've shown the Duelund tinned-copper capacitors with same 8-ounce coffee cup for a size comparator.
Each Duelund CAST tinned-copper 10uF capacitor is 6 inches across (15.24cm), 1 1/4 inches tall (3.18cm), and weighs 1309 grams (2.89 pounds).
The CAST base of the 10uF Duelund CAST tinned-copper capacitor is shown with 8 oz. coffee cup for a size comparator (above).
Duelund CAST Tinned-Copper 0.82uF capacitors for C3
Each Duelund CAST tinned-copper 0.82uF capacitor is 2 7/8 inches across (7.3cm), 3/4 of an inch tall (1.91cm), and weighs 153 grams (0.34 pound).
The 0.82uF Duelund CAST tinned-copper capacitor is shown with the same 8 oz. coffee cup for a size comparator.
I hope the descriptions and photos gives you a better feel for what these Duelund CAST tinned-copper capacitors are like, they are individual works of art and really are amazing to behold in person!
Pricing for the Duelund CAST tinned-copper capacitors is about 10% more than the pricing of the Duelund CAST pure copper foil capacitors, with the price difference reflecting only the more expensive tinned-copper foil used to construct them.
