The Use of Ferrites, Power Quality and It's Affect on Sound Quality
Fred Stanke | Published on 6/29/2021
The Use of Ferrites, Power Quality and It's Affect on Sound Quality
by Fred Stanke
I think my obsession with clean power started with me noticing diurnal variation in sound quality, a fairly well recognized effect: things sound better at night when fewer people and businesses are drawing and corrupting PG&Es 60Hz feed. I acquired a PS Audio P3 regenerator which largely removed the diurnal variations. Subsequently, when we had hired an electrician for some other work around the house, I asked him to install a direct line from distribution panel to my listening room, and that was a real ear opener, a very cost-effective improvement in sound quality. At that point I noticed that the P3 improved the sound in the middle of the work day when PG&Es feed is not so clean, but actually degraded the sound in the evenings when the power from the wall was clean. I sold the P3. I have also demo’ed some Shunyata cables and their Denali conditioner, and found that Level 3 Power Cord (anticables.com) with ferrites was a superior option.
A good technical explanation of what is happening is http://audiosystemsgroup.com/SAC0305Ferrites.pdf. It points out that toroids block undesirable "common mode" high frequency currents on cables, and not the equal and opposite differential-mode currents that the hot and ground wires in a power cable must carry. So I have been careful to always encircle the hot and ground of any cable together with ferromagnetic toroids. Others have reported deleterious effects with using filters "in" power lines, which is different than the approach reported here. Shunyata, I think correctly, points out that power supplies want to draw power from the supply with very rapid transients whose frequency components extend way up beyond the 60Hz mains frequency. E.g., an inductor in the hot power lead can impede such with negative repercussions. As long as such transient draws on the mains current are equal and opposite in the hot and ground leads surrounded by a ferrite, as desired, they are not impeded.
I started with putting one ferrite on each of my power cords, and found that it improved the sound.
It was this article that convinced me that it was worth trying ferrites on interconnects. I was intuitively and wrongly under the impression that ferrites on interconnects would roll off high frequencies. However, the article above explains why that does not happen and my experience confirms that.
I started with putting one ferrite on each of my power cords, and found that it improved the sound. I then tried four ferrites on the cords, to see if I could hear the difference. I could, easily, and it was an improvement. I then went to 13 ferrites on the power cords, which gave even further improvements. I followed a similar testing approach with ferrites on phono, interconnect and headphone cables, with similar results. I now operate on the principle of using as many ferrites as I have, that fit and are convenient to use.
While I have had good luck using ferrites purchased from Amazon, I sort of prefer using ferrites from: Round Cable Snap-Its Archives - Fair Rite (fair-rite.com). I *think* that the “type” that is most effective for our application is Lower & Broadband Frequencies 1-300 MHz (31 material), but I do not really know that. I will eventually open a thread re. this in our forum, and hopefully others can help flesh out our knowledge. At Don’s a week or so ago some members heard a mish mash of that and Broadband Frequencies 25-300 MHz (43 & 44 materials). For cable runs you want the smallest ID that will pass your cable, and *probably* the largest OD and length available that you are willing to put up with. In cases where my cable is longer than I need, and, especially, if ferrites in my stock have a much larger ID than the cable’s OD, I coil the cable, and each ferrite then captures multiple coils. When you do this it is critical that the current in the hot leads of all the coils *is going in the same direction*. In other words, do not fold the cable back on itself. Coil it. Where my power cords are rather longer than I need, I coil them and then clamp multiple ferrites around the coil. Orders can be placed at Round Cable Snap-Its - Category Search - Kreger Components, Inc.
Ferrite Round Cable Core Assembly - 444176451
I have found that adding ferrites pretty consistently improves the sound along a number of “dimensions”, which I will describe with my terminology. Bass has better “grip”. It paradoxically becomes less boomy and more prominent musically at the same time. I *doubt* whether there is more bass in the power spectrum, but have not done the measurements. Spatial imaging is more precise, both laterally and in depth. A result is that there is more “air” between the performers. The impression of performance in a real (with classical and folk) or virtual (with rock) space is improved. I *think* this is the result of enabling our ear/brain systems to separate direct from ambient sound, a skill that was certainly a life and death matter at least for our ancestors. Timbres become more distinct. It is easier to hear continuously which instruments (including vocal chords !-) are contributing to the ensemble. I find this also counterintuitive.
People often speak of this or that tweak being particularly effective for some class of instruments. With more ferrites, all the instruments become more themselves and get less in the way of others. For me, this allows compositions “to make more sense”. I get closer to the composers’ intentions. Also, with ferrites I “inadvertently” hear the performers playing with their virtuoso skills that got them onto a commercial recording in the first place. The clarinetist who has one measure of prominence in a large symphonic work is putting their absolute all into that run of notes, and with ferrites that can be more obvious. I often find that intelligibility of singing is improved. In summary, adding ferrites is like removing fog from a visual experience. Unlike so many adjustments we might make to our audio systems, you cannot go to far. Less fog is better. However, the punchline is: they are cheap !-)
But why is there so much fog? I long to do measurements to verify this, but have not, and it probably would not be easy. I will go out on a limb here and hypothesize that ferrites are removing correlated noise. White noise, hiss, is uncorrelated noise. It’s just always there, at whatever level. Its character is so different from that of the typical source material that our wonderful brains can filter it out, just like they do with audience noise at a classical concert. Correlated noise is noise whose amplitude and character is related to the source material, and is insidious because it gets through our cognitive filters. An example is noise from the rectifiers in the power supplies which will depend on how much energy needs to get passed to keep up with the program material.
Don let me do a power-cord demo at his phono-preamp shoot out, and many members were impressed with the effects. I hope that many of you will get a chance to play with ferrites in your systems, find that they can produce real improvements for a modest outlay and let us know, good or bad, how your experiences go.
Peace