Belden ICONOCLAST Interconnects and Speaker Cabling

I predict that once I finish painting the ceiling over the R speaker the problem will mysteriously vanish :wink:


Just don’t fall into the floor below!

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That should do it! :crazy_face::blush:

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What is everyone’s experience with respect to the settling time for the Iconoclast Gen 2 (UPOCC) interconnects? :thinking:

I put in a pair a couple days ago between my BHK pre & BHK-600’s, and they definitely sound ‘lean’ compared to what I had in there before (AQ King Cobra). The King Cobra’s were the only 2M XLR’s that I had on hand when I went from a stereo amp to monoblocks, so it’s the only thing I have to compare to right now, but the overall sound with them in the chain is outstanding.

I don’t want to give up on the Iconoclasts prematurely, but the first impression was a little disappointing, given everything I’ve read on this thread.

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Any time you move air tubes on XLRs give them 125 hours to reform dielectric with UPOCC conductors touching new spots on the Teflon.

Yikes! Something new to worry about!


I’d like to hear @rower30 weigh in on this.

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I’d recommend throwing them away and getting a nice pair of Bose. You can leave them in my driveway my trash pick-up doesn’t question the occasional large object.


The air tube ICONOCLAST series I and II will indeed be balanced differently, and more correctly, than most interconnect. They aren’t lean as much as the higher frequencies are flatter with the Vp alignment and air dielectric. Listen awhile and then switch back, you’ll notice the missing information. Typical leads are much warmer and yes, will sound that way. I chose to mitigate the linearity as best you can in the designs and few really try to do this, so it won’t surprise me that people feel they are different. Yep, and I like the difference, but it isn’t always what will be best for everyone.

As far as break in, the AIR is the primary dielectric so that’s not going to break in. The dielectric is FEP and already is a super stable loss tangent / absorption factor plastic. Do what makes you comfortable, but little break in is needed.

Also, the center conductor is wrapped in a Teflon coated thread, and this is closest to the wire, not the outer FEP tube. Moving the cable won’t move the spiral wrapped threads touch point. The farther you go from the center wire, the less the dielectric impacts the sound. The magnetic field drops with the square of distance, and it is low to begin with.


I didn’t break them in when I designed and listened to them to settle on the design, and they still sound very good to my ear after several years use.



Much appreciate the detailed explanation Galen. :slightly_smiling_face:

To be fair…the Iconoclasts weren’t exactly put into a fully stable system. The BHK-600’s that they’re feeding just went into service Monday, and I put the Iconoclast IC’s in when I got them on Tuesday, so the amps are probably still changing in character as we speak.

Earlier today, I bumped the level 1 or 2 clicks on all four REL subs ( I originally dialed them in with the AQ King Cobra IC’s in the system). I did a lot of listening this afternoon, and the overall presentation was MUCH better…more than would be attributed to that minor tweak on the subs…making me think the amps are still coming into their own. Right now, everything is playing together beautifully. :grin:


The adjusted Vp is most evident in the higher frequencies as there is a wider Vp gap between lower to higher frequency points. Vp moves from 10% to about 50% @ 20Hz and 20KHz respectively. The changed time alignment impacts how the signals superimpose one on top of the other and this changes the signal. Above about 10 KHz it is all those harmonics that make stuff sound real. There are no fundamentals above 10 KHz.

The cables are short in length relative to the Vp wavelength speed of even 10% the speed of light. This fact does improves the inability of the signals to change in time, but it doesn’t remove it. ICONOCLAST further mitigates what we can with the cable’s design.

The lower frequencies are impacted by the cable’s load tested open-short impedance and based on the ratio of the cable to load impedance.

ICONOCLAST RCA and XLR cable are about 2,300 ohms in the very low frequency range.
ICONOCLAST speaker cable is 350 ohm in the very low frequency range.
The impedance mismatch is a problem for speaker cables but not so much interconnect, why?

Interconnect cables have a far higher open-short low frequency impedance than speaker cable, like they are around 2,300 ohms! Yes, 2,300 OHMS. Is this a problem or not we have to ask. It isn’t when we look at the RCA or XLR cable input resistance, which is technically supposed to be infinity but is 47K-OHM target resistance. The input impedance is so high, infinity, that the voltage divider rule says most of the signal is dropped on the higher of the two values. The “infinity” resistance input load is way higher than the cable so that 2,300 ohms, although high, is a high ratio divided into the input resistance and is OK. We have no current to speak of so capacitance has always been the “problem”. Voltage is what we have left so why wouldn’t it be? Capacitance affects the voltage properties.

Why is the IC so high impedance in the low end and should we make it lower? It is higher because we want to make the IC cable’s capacitance LOW, and this raises the low frequency impedance, a lot. A decision has to be made, which is worse, the voltage distortion with higher capacitance or the matching impedance? The choice on IC is the capacitance and higher frequency Vp alignment. Current is nil as the load is technically an open circuit. Capacitance control it is. Most all the signal is seen across the load at low frequencies. At RF, we have a different situation with matching that doesn’t apply to audio as the wavelengths are too long to be resonance reflections that cause RL, Return Loss. RF resonance reflection is a different issue than the voltage divider rule that applies to low frequency signals which is DCR influenced. RF is the reactance causing a mismatch to the load in an ideal cable (always the same vector impedance magnitude).

Speaker cable is different, the cable is far closer to the input impedance, 300 cable and 8 ohms speaker respectively. We do want to mitigate the low frequency open-short impedance as best we can. The ratio of cable to load is far lower. By tuning the capacitance, higher to lower, and the open-short impedance we try to control the common reflections with high current signals. We have a lower voltage, 50 volts or so, but high current, 23 amps and more, into speakers. The current reflections to the load mismatch is worse than the cable’s capacitance effects on the voltage signal. To control the Vp alignment raising the capacitance, we also need to use a much smaller loop DCR AWG wire and many of them, to lower DCR. This makes sure the voltage signal is seen across the load and not the cable. We still can’t ignore the voltage signal. We need to increase the speaker load to cable ratio by lowering the cable DCR well below the speaker load DCR. We do that with aggregate cable AWG size.

ICONOCLAST is a thought exercise on the impacts of a non linear system, our cable, on the signal. What can be done to improve the cable’s basic linearity and why? The cable now exists to be compared to the more cost effective designs that are not as well optimized. Does it matter?

All cable designer’s have to look at the load value and determine how to make the cable most linear into that load. We can also assume it doesn’t matter and use zip cord. The math says otherwise, and then we need to compare the ears to the math and decide what’s best for us.

I hope this makes your cable trials more interesting for you, and how it all works as a system. No one gets around any of this. We do have options for the RLC variables we design-in with the math and how the cable actually reaches them…and that’s not easy to do.