Steen Duelund: introducing a Danish sound pioneer
Steen Duelund (1943 to 2005) sits somewhere between what you might call audio craftsmanship and audio experimentation, a slightly mythical figure and to some a slightly esoteric one. He’s best known for favouring natural materials, silver, silk and linseed oil, alongside a scientific bent. He trained as a mathematician, and worked across crossovers, cabinets, modified drivers and cables, all framed by psychoacoustics.
I first came across Duelund, and his thinking on interconnects and speaker cable, in the mid-90s as I remember it, while I was in the research phase of a speaker project (Speak & Abyss from Dansk Audio Teknik). As I recall, it was all pure DIY territory back then, unlike today where a good deal of it is manufactured product.
The line of his I keep coming back to, from a High Fidelity interview: plastic is an evil and should be eliminated wherever possible. No plastic dielectrics in capacitors, none as cable insulation, none on the coil formers you can’t avoid if the big inductors in the bass section of a crossover are to have low DC resistance.
Duelund’s cable philosophy: silk, silver, linseed oil
Lately I’ve come at this through two figures in sound, Peter Qvortrup of Audio Note and Alan Shaw of Harbeth. Both managing directors, both people who take part in public debate, Peter in long discussions on forums, in YouTube interviews from hifi shows and on YouTube channels. I intend to return to both with more thoughts later on. But for both of them it holds that they’ve been a great inspiration for the latest legs of my journey through sound reproduction and music.
The linseed-oil origin story, in Duelund’s own account (my translation from English): it struck him that linoleum floors don’t build up static, and linoleum is high in linseed oil, an oxidising and drying oil. He tried it as a surface treatment for the cable. Dipped first, then dried at 60 to 70°C for two or three days. He’d feared it would make things worse; instead the listening result exceeded all expectation and beat the gold-plated cable.
Objective measurement vs subjective judgement
Duelund again: of course it’s subjective, since the whole point is producing what we as human beings perceive as good sound, which is a subjective exercise in itself. On the other hand, measurements, electrical and acoustic, are extremely important tools in the process, and real progress would be impossible without them. The thing to keep in mind, he says, is that we tend to measure what we can measure rather than what we perhaps ought to.
Should cables have a sound? And do they?
Some hold that cables can and should be a very active component that shapes the sound in different directions. Others that the signal is fundamentally clean from the start and shouldn’t be coloured by a cable in any way. And others that both positive and negative effects can arise in the interplay between, say, DAC, preamp, power amp and speakers.
I’ve moved from the second camp towards the third, in a soft position, or however you want to put it. And it’s an area I need to read more about. Skin effect, for instance, and Litz cables, where I can see more and more people demonstrating a concrete measurable difference against, say, ordinary fairly thick copper, or as here tinned copper, where something similar to the Litz effect may be happening.
Then there’s a passage of Duelund’s I love, about the concert hall: you bring two ears and your brain, with whatever sorting system that particular brain happens to have. Every listener directs their attention at something different, and the listening experience gets sorted, parts of it emphasised and parts suppressed, entirely individually. He recalls an opera where the female lead was laced so tightly that the effect of her breathing on the upper harmonics pulled his attention clean off her singing and onto her breathing.
Where it all started for me
My interest in sound reproduction was on standby for a long stretch, when my focus was more on the music. In connection with a move and buying new speakers (Harbeth M30.1) I read up a bit on different speaker cables, and ended up with a set of DCA20GA wound in two strands for the + terminal and two for the −. That beat my previous cables and a control run with a shielded Mogami W3082 (2.0 mm², roughly 14 AWG), which I’d got the urge to try after seeing that virtually all of Audio Note’s speaker cables are shielded. Something a lot of people consider unnecessary for cables carrying signals that strong.
Cables developed during covid
During the epidemic I spent a fair amount of time listening to music and researching the principles of recording and reproduction. I got in touch with Marcel from Thessaloniki in Greece, whom I came across in an audio forum, where we swapped ideas and thoughts. He’s spent many years making custom cables based both on his own designs and on Shirokazu Yazaki designs, often built on Belden stock.
We landed on DCA20GA, made by the Danish-run Duelund Coherent Audio, combined with Switchcraft plugs, which I’ve had good experiences with before on interconnects built on Belden 8402 (which is really a microphone cable) soldered with Cardas Quad Eutectic Silver.
A little while back Thomas, who bought one of my prototypes, wrote a few words that made me really happy. He said he was a happy man but hadn’t quite been able to believe his ears at how much impact the cable had had on his system, so he’d spent a few days check-listening with different music before reporting back: the tops of vocals sound less strained, the bottom has tightened up, in passages with a lot of information the picture stands much clearer and instruments sound more correct. Piano especially, and one of his reference tracks where for the first time he heard a harmonica at full tilt without it sounding pinched.
I didn’t know Thomas beforehand. He got in touch off the back of a for-sale ad in the Facebook group Brugt Hifi køb og sælg dit Hifi. He runs the cable between his phono stage and his preamp.
Update, January 2022: Audio Note cables
I thought it was time for a short update on the testing of various cables. On Duelund vs Belden, the outcome was that the Belden cables gave the best sound overall, after swapping back and forth and listening many times over. Into the heat now come two sets of Audio Note AN-CABLE-150, terminated with Audio Note’s own RCA plugs.
In the comparisons it seemed at first that the Duelund cables were more detailed, precise and open in the sound, to use some of the terms people tend to reach for. Belden fuller and with a far better defined bottom end. The Audio Note cable more balanced and more right-sounding. So that’s what I’m carrying on with for now. Audiobeatnik has a comparison of DCA16GA and Belden 8402.
Cables I’m listening to at the moment:
- Belden 8402 with Switchcraft 3502AAU plugs (0.5 m, terminated Yazaki-san style)
- Duelund DCA20GA from Duelund Coherent Audio with Switchcraft 3502AAU plugs (0.5 m)
- Duelund DCA20GA from Duelund Coherent Audio with Switchcraft 3502AAU plugs (0.7 m)
DCA stands for Duelund Coherent Audio, just as the original Western Electric cables were called WE16GA. GA indicates that the thickness follows the American Wire Gauge standard. The scale runs backwards from what you’d expect: the lower the number, the thicker the cable. AWG 20 = 0.812 mm, 0.5166 mm², 4.6 kg/km.
Other RCA plug options: KLE & Audio Note
I’ve had an email asking about alternatives to the Switchcraft 3502AAUs, and whether I could recommend something better. I’ve only got experience with Switchcraft on this project, but it’s very clearly a place where you can upgrade.
Duelund Coherent Audio’s own plugs, with rhodium and what looks like compressed paper, are the obvious next step. On hifi4all.dk I’ve heard of good experiences with Harmony plugs from the Australian maker KLE, whose plugs come in three tiers at different price points. Do leave a comment below if you have good experiences (or bad ones) with either type.
For myself I’ve got my eye on Audio Note’s AN-GP-AG and AN-P RCA plugs, perhaps combined with a construction using one of the silver cables (silver 1.0, 2.0, 3.0), though there may be a problem with the cables being too flat or too wide, so I need to work that through first.
More Duelund quotes to reflect on
That it seems to him the sound in newer equipment has become dull and undynamic, in certain designs almost shrill or somewhat synthetic-sounding and unpleasant to listen to.
That products have appeared leaning heavily on the technology, measuring damned well, and sounding cold, clinical, unmusical.
And that one man alone can’t take in the whole chain; here we need help from those who reckon they understand each part, analogue as well as digital. But it seems to him clear and universally true that the plain, the simple and the mathematically beautiful are to be preferred.
The difference between DCA12GA, DCA16GA and DCA20GA
In the image below I’ve marked the three thicknesses and constructions the cable comes in: 20GA, 16GA and 12GA. The diagram shows both diameters and resistance, the latter being particularly relevant when calculating the optimal thickness for speaker cable. There are two routes: either find a thickness in a single cable that suits the length you need, or run several strands of a smaller diameter.
Further reading: Jeff’s Place & The Audio Beatnik
Jeff’s Place / Positive Feedback
Jeff has blogged about Duelund-inspired cables several times over, and has experimented with them as interconnects, as speaker cable, and for internal wiring in his Tannoy Westminster Royals. The chronology of his journey is a bit hard to follow, but try starting here. He’s also written specifically about unshielded interconnects on DCA20GA.
The Audio Beatnik
There’s a fair number of articles on The Audio Beatnik too, again on both interconnect and speaker-cable use. The chronology is a little scrambled here as well (I know full well I’m often guilty of the same thing).
If it isn’t going to be Duelund
As I mentioned further up, I also listen to interconnects built on microphone cable from the American maker Belden. Belden 8402 is a shielded mic cable based on tinned copper, the same principle as the Duelund cables. There are two conductors in 20 AWG wrapped in EPDM (synthetic rubber) in a pleasant vintage brown.
The cable is fairly soft and easy to handle, pull, twist and angle. On Jeff’s Place it’s used to connect an AN-S4 SUT (a passive step-up from Audio Note) to a Leben RS-30EQ phono stage, and the RS-30EQ to a Triode Lab 45 EVO SET integrated. Jeff’s verdict on that combination is that it’s absolutely breathtaking, with well-recorded material like Jim Hall’s Guitar sounding startlingly realistic.
Old ad from Den Blå Avis, the cable sold in half an hour
I’m selling two Duelund interconnects (some would insist it’s more correct to say Duelund-inspired cables), that is two strands, so four RCA plugs in all, enough to connect a DAC to a preamp, a streamer or CD player to a preamp, or a CD player to an integrated amp, with RCA plugs from Switchcraft (model 3502AAU). In my experience the cable isn’t suited to connections between preamp and power amp.
The cable is based on DCA20GA made by the Danish company Duelund Coherent Audio and consists of tinned copper strands wrapped and woven in cotton, treated and dried with oil instead of plastic materials. A technique that draws on Steen Duelund’s thinking about plastic’s effect on the sound (in the negative direction) and the discovery that linoleum floors, which have a very high linseed oil content, hence the name, don’t build up static electricity the way other floor types do.
I remember that in the 90s synthetic carpet was a dangerous cocktail in the computer shop I worked for, because the static settled in your body and plenty of expansion cards were killed during installation that way, until we got thin wrist straps with an earth connection.
The cables are 0.5 m, and + and − are told apart by the fact that one has a red marking (+) in heatshrink while the other is unmarked (−).
Mark I was the standard cable. Mark II got an extra treatment with bleached linseed oil and was then dried for five days.
I’m selling because I’ve had a series of prototype interconnects made, shielded and unshielded, including three sets of Duelund cables on DCA20GA in different lengths and with different oil treatments.
