Scenes From Future Reviews
Duelund Drama
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Figure 1. Duelund resistor placement mockup.
Paper cutouts with the same footprint as the Duelund CAST resistors were arranged on the back of a prototype sample of my SDA SRS 1.2TL crossover board. I ordered long leads and how long the "long leads" were. This is the response I received from Duelund:
"They are made so they easily cross each other on the middle of the resistor. I make them by hand, so I just make them looong."
Based on that vague, non-quantitative reply, and knowing that the resistors were 5.3" long, I guessed that the leads would be at least 4" long. The actual leads measured 4.2" to 5.1" long.
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Figure 2. Actual resistor arrangement.
Due to the locations of the resistor through-holes and obstructions on the back of the board, the 11.5 ohm resistor had to be stacked on top of the 2.7 ohm resistor.
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Figure 3. What a mess - Duelund resistors installed. The leads are covered with 3/16" shrink wrap.
The resistors were secured to the board with a pad of hot glue at each end.
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Figure 4. Cutout in the Sonic Barrier Black Hole damping material.
Sonic Barrier Black Hole damping material is placed between the circuit board and its same-size structural support board. I cut away the damping material in the area of the stacked resistors to avoid excess pressure on them. I found out the hard way that Duelund resistors are somewhat delicate.
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Figure 5. Licorice sticks, bricks and regular looking resistors. Clockwise from bottom left: original ceramic
metallic resistors, Duelund carbon resistors, Mills MRA-12 wire wound resistors.
Noise spectrum measurements with an oscilloscope showed that the Mills passed a cleaner signal than the cermet resistors and the Duelunds passed a cleaner signal than the Mills. The increase in transparency was immediately apparent, but it was more modest than I expected.
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Figure 6. One lead of one of the 11.5 ohm resistors broke off with normal handling during installation. I
soldered it back on. Duelund is sending a replacement.
In all my years and years as an electronics hobbyist since teenage, I have never had a component lead to break...until now...with my $65 a piece boutique resistors.
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Figure 7. SDA SRS 1.2TL crossover board with Mills MRA-12 resistors.
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Figure 8. SDA SRS 1.2TL crossover board with Duelund CAST Silver resistors on the back.
I received this reply when I asked Duelund about break in time for the CAST Silver resistors:
"5 days good playing."
Since I don't know what a day of good playing is, I am going to assume it is a typical day's listening, say 10 hours, rather than an entire 24 hour day. That would generously put "5 days good playing" as 50 hours. Since I am letting the radio play overnight and when I am away from home, it will only take a little over two days to reach the equivalent of "5 days good playing". As of now, I have 27 hours of listening time on the Duelunds.
After the Duelund's are finished soaking, I can play with my new Pass Labs XP-30 preamp:
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Figure 9. According to Pass Labs, the XP-30 requires 36 hours of warmup from a cold start.
This was a one month old dealer demo, so I assume no further break in is required.