Enhanced bass and treble. Extra midrange disappears. More realistic sound.

Requires a lot of time and energy for configure it for your system. Sound shows the irregularities of your power source. You have to turn up the volume. It sounds absurd but you have to tune the sound by sliding the units on the power cord, especially on the radio tuner.

I am sure that the use of these units widely varies, depending on your system, power supplier, and hearing. I must have been given these stoppers because they are quite difficult to handle properly. You need A LOT of time and patience to configure them on your system, otherwise they can do more harm than damage to the sound. I use these units on power cables only. (I found that they made no difference on interconnects.) First I put one on the (audiophile)power cord of my amplifier. At first it sounds like they take away from the dynamics. Then you realize that what is lost is an extra amount of midrange. Bass and high treble are enhanced. The sound stage is more realistic for classical music concerts, but you lose the cheap sound that is audible at low levels. I have a lot of power cables attached to a hub, so I tried to put one stopper on the hub's power cord. All sounds suffered. Then I wanted to prove the linearity of the effect, and added another unit, next to the previous one. Incredible. Everything fell into place. After trying a number of configurations, I ended up putting one on the stereo amplifier two(!) on the power distributor's cord, and another on the FM tuner. To my great surprise, the sound shows the irregularities of your power source, which can be disturbing, especially in the morning and early afternoon (sound is better at night on all systems). It sounds absurd but you have to tune the sound by sliding the units on the power cord, especially on the radio tuner.

Similar Products Used:

Special power cables and high/end interconnect cables.

Grate at stoping line pollution from other electric devices. Refrigerator is a big one.

Does more harm than good on audio and video.

This product did more harm to the sound than it did good. It removed noise and improved clarity but decreased the dynamics and warmth of the music. But on the plus side, I added these to other things in my apt with grate results. I put two on my refrigerator, lamp, clock, Etc. It stoped outher electrical thing from adding noise in to the power line.

Absolutly None! Doesn't even work with TV or cable box power cords. TV pictures look the same with or without the filter.

Robs audio system of air and detail. Complete waste of money.

This is the only audio tweek I have ever used that actually produces a dramatically negative result! When you apply them to interconnects or power cords, it very noticeably robs your system of high end extension, upper midrange detail and air/ambiance. Unless you have a extremely cheap gear with a nasty high end, stay the heck away from these things! Please!!! Associated Gear: Audio Research SP-11 MK2 Preamp McIntosh MC240 Amplifier Joseph Audio RM22si Speakers Rega 2000 CD Player Audiotruth Diamond X2/X3 (IC) Acoustic Zen Matrix Reference MK2 (IC) Transparent Music Wave Super (Spkr)

if there is a problem with RF they work otherwise they don't
Yes they are expensive but stronger than the similar products found at stores.
Worth the money ? depends on the problem you might have...
Great combination the special AC ferrite with the brown 3.3 AC power cable.
The other ferrrites for the interconnects didn't work for me. The sound was dark and compressed.

So the rating is only for the the big ferrite ring with the AQ 3.3 power cable.

Similar Products Used:

Various ferrite types from computer & electr. stores

Hi there,Recently, I bought a set of Audioquest RF Stoppers, where "RF" apparently stands for "Radio Frequency". These ferrite-cores can be tightened around interconnects, thus suffocating the radio-frequencies that are picked-up by the interconnect (which acts like an antenna), or similar high frequencies that are generated by your CD-player. I find the effect sensational. The results are a more relaxed sound, more details over the whole frequency-range, a better soundstage (the sound coming more "from the center"), better definition of musical instruments, etcetera. Every "high-quality listener" should try these!
Greeting from the Netherlands,
John van Polen

they soften harsh highs somewhat

they ruin the harmonics and coherence of a good system

I got these for free after inquiring about them at my local high end shop. (Guess it pays to spend some money eh?) Slapped them on and thought they were an improvement. Six months later I was still wondering how to get the "live" sound out of my system that I had heard so many times at the shop. On the advice of a friend, I took the stoppers off...holy unleashed coherence batman!!! These things do "smooth" the top end...but they also roll off the very top where some of the most important harmonics live. This has the net effect of closing down the system and ruining the "harmonics clinging to the source" type of magic that transports you from just listening to your stereo to a place where the music lives in your room. Having said all that, I suppose that if your system is bright or just plain snotty up top, you might prefer the sound with these things, but the better solution is to fix the brightness in your system, not just try to mask it.

Similar Products Used:

AQ Interconnects
Tara Labs Interconnects

Eddy is should read my review more carefully; I explained how its works. The audio signal is not RF, but the interlinks act like an antenna and do pick up RF from the air. This RF now is suppressed by the ferrite-core. I thought that was clear, I hope it is now. I agree they're somewhat overpriced, like most tweaks from Audioquest. Indeed, there are ferrite-core's used on computers; the RF-stoppers have the advantage they fit like a gloove around my Audioquest interlinks. For power-cables, I should have used cheaper one's. (What a money-waster I am !). There is no doubt it works; however I guess the effect is hardly audible on a "standard" set-up; on my rather "high end" set-up (Thiel/Classe), it is. Nevertheless, some would argue, it's only marginal and therefore not worthwhile; I my case, I welcome any improvement of sound. For me, it's worth it.

It is over-priced. If you believe it is working for you, you can buy it from any computer store or electronic hardware store for 1/10 th of it price. However I do not think it is working on audio cable because aduio signal is not RF. It may works with digital cable.

For a small block of ferrite, these are definitely overpriced. You can get ferrite blocks over the net for a few cents each. They do work, especially on video cables (that's why computer monitors used them) but don't get ripped by paying more than $5 for it.

looks cute

doesn't work

I have a serious and known RFI problem with my phono preamp (Creek OBH-8SE) At the suggestion of Roy Hall, of Music Hall, the US importer of these preamps, I purchased some RF stopper juniors to try to deal with the problem. Absolutely no effect.

Other may imagine that these produce more "air" or "clarity" or whatever in otherwise correctly working systems. Who knows? Could be or could be the placebo effect. All I know is that, with a real RFI problem, these things did not work, no matter where I placed them -- on ac cord, on interconnect, on power pigtail between powersupply and preamp. Save your money.