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RF Stoppers

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10 replies to this topic

#1 of 11 OFFLINE   NickK



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Posted February 26 2003 - 11:47 PM

Question... might be real simple, but I want to ask anyway.

Can someone tell me or point me towards info on RF Stoppers and if they are really good for your system, really improve quality,, etc? I saw a good deal on a set of ten, and I was wondering it it really improves things to use them.

#2 of 11 OFFLINE   Bob McElfresh

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Posted February 27 2003 - 06:03 AM

Uhhhh... these sound like a bit of a gimmick.

There are power strips for your AC power that offer "RF Filtering". The theory is that the long power wires act like AM antenna and may feed AM signals into your equipment. I've yet to hear of anybody with this problem so I'm not really sure it's worth much.

A much more common/real problem is the CATV coax picking up a 60 hz humm from power wires and creating a low humm noise in your speakers during quiet passages. But to solve this you WANT to pass the RF signals (thats what CATV signals are) and stop the 60 hz signals on the CATV coax.

#3 of 11 OFFLINE   NickK



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Posted February 27 2003 - 06:53 AM

This is the site I saw them at.....


#4 of 11 OFFLINE   Danny Tse

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Posted February 27 2003 - 07:11 AM

You can get these at Radio Shack. And you don't have to buy 10 of them at a time.
SACD not listed at sa-cd.net (updated 8/26/2009)

#5 of 11 OFFLINE   NickK



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Posted February 27 2003 - 07:58 AM

But they do work? And are beneficial?

#6 of 11 OFFLINE   TimForman


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Posted February 27 2003 - 08:19 AM

Yes they do work. Some people on HTF have used them and reported positive results. These are standard equipment on many personal computers for both video and AC power. But I'm reminded of an old adage: "If it ain't broke, don't fix it". One thing is for sure; Don't pay $17.50 a piece for them.

#7 of 11 OFFLINE   Danny Tse

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Posted February 27 2003 - 09:18 AM

These RF stoppers are also on Radio Shack's new line of audio/video cables. Check out the photo.
SACD not listed at sa-cd.net (updated 8/26/2009)

#8 of 11 OFFLINE   Chu Gai

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Posted February 27 2003 - 10:01 AM

their effectiveness really depends upon whether you have any RF that's infiltrated your lines and whether your equipment needs 'assistance' in dealing with it. it's really a very tough call, but at least with RS, there's no s/h and their return policy is excellent. there are a variety of types of ferrite beads that work on different areas. try a google search on the terms 'ferrite beads' 'choke' and get a general overview.

#9 of 11 OFFLINE   Brian OK

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Posted February 27 2003 - 10:55 AM

I would recommend you be very judicious in your use of these RF devices. RS, the low cost option, is your best bet for any audio/video use "tryouts".
I would never recommend them on video cables, analog interconnects, or digital coax cables. If you want to use them in your system, try them on your AC cords, fixed, or aftermarket. Whatever you have.... your RPTV's fixed cord for instance.

These things do work..... sometimes for the worse :.(

I have purchased the same Audio Advisor RF "snap-on" from the likes of Audioquest in the past.........

.....they now reside on my 2 'puter AC feeds, 2 refrigerator AC cords, and a puter printer and stuff like that. Not on the A/V gear. These things can choke a "non-RF plagued system to death", IMHO.
But they do work ;^)


#10 of 11 OFFLINE   Brett DiMichele

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Posted February 27 2003 - 09:46 PM


Care to elaborate on "They can Choke a NON RF Plagued system
to death!" ?

I run RF Chokes on my LP RCA's and on the In/Out RCA-XLR's
from my Pre to my Tube Ultra-Q to my Power Amp and I noticed
no audible degredation in sound at all.
Brett DiMichele
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Too Much to list!
My PhotoBucket              My Buttkicker Wireless Advance Kit Review

#11 of 11 OFFLINE   Chu Gai

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Posted February 28 2003 - 12:53 AM

i just clicked on that audioadvisor link...sheesh...5 bucks each plus s/h? Well it is red...very striking and gives that 'je ne sais quoi' look to your equipment. Important if you spend more time admiring the back of your equipment rather than sitting down and listening or watching TV.
Well a click to their 'informative' specifications gives...
AudioQuest RF Stoppers have an internal diameter of 10 mm.
They add 245 ohms of impedance at 1 MHz, greatly reducing RF interference.
Very f****** informative!
These ferrite materials come in a variety of configurations: beads, cores, split, bars, etc. and in a variety of internal diameters.
If you need additional impedence you can do one of two things. If you're using the split ones and you add a second one, the impedances become additive. If you're using a core, and you loop the wire through it, the impedance is increased by the number of turns squared. If you're investigating whether the power cord is a source, then you'd be looking to get a big ass core and loop the cord several times.
Ferrites are typically given 'numbers' that indicate the 'mix' and what their performance characteristics are.
#43 used for when your signals are in the 0.01 to 1 mHz range. Once you go above those frequencies, it starts choking or attenuating the signals. It's generally considered effective in attenuating frequencies from 1 to 1000 mHz. It's a general use material, probably the one that AudioAdvisor is selling.
#61 will attenuate signals 100-2000 MHz. It'd be considered if your signals happened to be in the 0.2 to 10 mHz regiion.
#72 or #73 mix are used if your signals happen to be in the 0.001-1 mHz region
#77 will attenuate signals 5-100 MHz
There's a ton of ferrite mixes out there designed to solve particular problems. Their degree of attenuation, the maximum frequency that they'll attenuate, the broadness or "Q" (like in parametric equalizers), are various parameters that can be manipulated by the manufacturer.
In a generals sense, when you purchase the beads you've got to specify the physical size and the mix (those numbers given above). For example:
FB 23 and FB 63 have 0.2" holes
FB 56 has a 0.25" holes and it'd be used for RG58 or 59 coax.
FB 124 has a 0.5" hole and would work for larger cable like RG 8.
It doesn't matter if the ferrite is bigger than the cable and hangs loosely but then it doesn't give that 'finished' look.
If you don't like RS, there are several online places, even ebay, where you can pick these up. For example.

You could, if you wanted to try, putting one around the coax going to your TV. That'd address any RFI issues, if there were any, with respect to the outer shield. However, most problems with regards to TV's have more to do with improper or non existent grounding of the cable shield which can, under certain circumstances, have flowing common mode currents. Possible approaches here would be to ground the shield to the ground on the outlet that serves the TV.
F Connectors, especially those installed by consumers, can be problematical. They can provide common path for RFI if the connections are not tight or if the connector is not cripmed or screwed onto the coax tightly enough, or if it is completely missing and the center conductor is just
stuck into the female connector!

There is some info on RFI in the FCC's Interference Handbook (which is free if you ask for them at 888-CALL-FCC), or it used to be.

For additional information you might want to consider contacting http://www.arrl.org/ which is an amateur radio site. Very bright people with practical answers to practical problems.

I'll leave to somebody else to give an email over to AudioAdvisor and see if they'll indicate what mix their using. Wouldn't surprise me though if they either don't know or use the old special and proprietary reply.