I want to share every step of the way with you about the Duelund-Altec crossover project that Frederik and I are embarking on, so that you can come as close to possible to experiencing the project as if you were doing the project for yourself.
A 32.30 kilogram parcel from Frederik (Duelund) arrived at 10:30AM this morning, containing the new state-of-art Duelund CAST tinned-copper capacitors, inductors, and resistors that will be used for building the crossovers for the Duelund-Altec Project.
I removed the boxes containing the Duelund CAST Sn-Cu components from the shipping container and laid them out on my coffee table.
Then I carefully unpackaged each box and removed the carefully wrapped Duelund CAST Sn-Cu components.
The schematic for Hiraga-style crossovers for the 16 Ohm Altec 803B low-frequency drivers and 16 Ohm Altec 804A high-frequency compression drivers of the Stokowski Altec’s is shown below.
Stock Altec crossovers have an adjustable high-frequency control to aid in achieving the appropriate high- to low-frequency balance in different rooms and/or for listener personal tastes, which is the knob on the right crossover in the photo below.
Adjustability is a truly useful feature that can be an enormous aid for getting the musical and sonic presentation of the loudspeakers dialed in appropriately.
I have added 16 Ohm L-pads to the Hiraga-style crossover design to facilitate balancing the high- and low-frequency drivers output appropriate to the room and my personal tastes.
Once the optimum high-frequency to low-frequency balance has been achieved the L-pad can be eliminated and replaced by a fixed resister if so desired.
To build a pair of the crossovers you need the following Duelund CAST Sn-Cu components:
- Six 6.6mH inductors for L1, L2, and L3.
- Two 18uF capacitors for C1.
- Two 10uF capacitors for C2.
- Two 0.82uF capacitors for C3.
- Two 140 Ohm 10W resistors for R2.
- Two 24 Ohm 50W resistors for R3.
- Two 100 Ohm 10W resistors for R4.
- Two 10 Ohm 20W resistors for R5.
Duelund CAST Sn-Cu 6.6mH Inductors for L1, L2, and L3
I’ll be interviewing Frederik and asking him to describe the details of each of the Duelund CAST Sn-Cu components in future posts, just as was done for the Duelund-Westminster Project, but at the moment I just want to introduce them to you.
Each Duelund CAST Sn-Cu 6.6mH inductor is 7 inches across (17.78cm), 1.5 inches tall (3.81cm), and weighs 3257 grams (7.18 pounds).
I wished my photos did justice to the incredible quality of these Duelund CAST Sn-Cu components, they are truly stunning to behold in person, with each one being a handcrafted work of esoteric audio art. I must admit I am rather in awe of them.
Duelund CAST Sn-Cu 18uF capacitors for C1
Each Duelund CAST Sn-Cu 18uF capacitor is 7 1/4 inches across (18.42cm), 2 inches tall (5.1cm), and weighs 2478 grams (5.47 pounds).
Duelund CAST Sn-Cu 10uF capacitors for C2
Each Duelund CAST Sn-Cu 10uF capacitor is 6 inches across (15.24cm), 1 1/4 inches tall (3.18cm), and weighs 1309 grams (2.89 pounds).
Duelund CAST Sn-Cu 0.82uF capacitors for C3
Each Duelund CAST Sn-Cu 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).
Duelund CAST Sn-Cu / Graphite Resistors
Frederik humorously refers to the new Duelund CAST Sn-Cu / graphite resistors as “Jeff-istors”, as their design arose out of a discussion where I shared my listening impressions with Frederik about trials with various prototype and other resistors.
Essentially, the new Duelund CAST Sn-Cu graphite resistors use multiple graphite resistive elements and larger (DCA12GA) tinned-copper leads to provide higher levels of musical and sonic performance.
If you imagine the size of a cigar, you’ve got the size about right for the new Duelund CAST Sn-Cu / graphite resistors, as they are 6 inches long (15.24cm). The vary a little in diameter depending on their resistance values, but if you think of them about as big around as your thumb you’ve got it about right. A Duelund CAST Sn-Cu / graphite 140 Ohm resistor weighs 64 grams (2.3 ounces).
Much more detailed descriptions of the new Duelund CAST Sn-Cu components will be coming in individual future posts.
Ok, that’s all for now, and as always, thanks for stopping by, and may the tone be with you!