10. January 2022 · Comments Off on Connected Fidelity RF Blockers · Categories: Accessories, Cables, Hifi News, Hifi Reviews · Tags: , , ,


Connected-Fidelity’s RF Blockers are small blocks that connect to your speaker binding posts and are intended to reduce RF noise in your system. Ken Stokes gives them a try for HiFi Pig. 

Conncected Fidelity RF Blockers

Connected-Fidelity RF Blockers with banana connections

When I was first asked to review these Connected-Fidelity RF (Radio Frequency) Blockers they were offered for review as part of a bundle, including a mains balancing unit and some speaker cables – reviews to follow. I have wanted to try mains balancing for some time, so although I was sceptical of these small units and the claims for products like this, I realised that I would need to review these RF Blockers as part of said review bundle. If truth be known, I really wasn’t sure what to expect of these.

As I say, I was to some extent sceptical, in part because I have read some fairly derogatory articles about ‘RF’ products; Zobel circuits and networks etc. and whenever they are discussed there’s usually very clear differences of opinion voiced – in much the same way that cable discussions end up. I guess it’s fair to say that some of the so called RF blockers sold over the years may well have not been made to a high standard, but I had been swayed at least to some extent by articles I’ve read. I am aware that such circuits have and are used in many pro environments; TV studio’s and telecommunications are two areas I know such circuits have been employed, presumably to good effect. I will make clear now though, I do not know what sort of circuitry is inside these RF Blockers, Zobel or otherwise, my mission was simply to try them for review and make conclusions based on what I did, or didn’t hear, and with construction and value in relation to any sound quality improvement.

I believe I had adequately attended to RF issues with my rig and have separated mains cables from signal cables fairly well and as a matter of good housekeeping. I use earth drain and screened mains cables and I have at least ensured mains at floor level and signal cables across the top at the back of my HiFi unit remain as separate as is possible. Most of the other cables I use are screened. I knew the noise floor was already pretty good and that there was no hum/white noise audible even with amp turned to full and without music playing. I also knew my system was already revealing. However, the concept of these units is pretty simple, that cables and some kit can act as an antenna, picking up airborne radio and wifi frequency signals and with suitable filters, these detrimental signals can be dealt with, although discussion around this topic is, as mentioned, divided and often heated.

As with anything sent I, was determined to give these small units a fair chance with proper long term listening and with A/B testing as I normally do. These units were sent on a try for review and if you aren’t impressed just send them back. I installed the blockers in my system, with no intention of critical listening at first, simply to just let them settle in if – any such settling was needed. These units are very easy to install, they simply plug/connect to speaker binding posts (or amp’ outputs) using optional banana, bare wire or spade terminations.

Coneected-Fidelity RF Blockers Spades

Also avaialble with spade connectors.


These RF Blockers came well packaged in a stylish solid cardboard box with more than ample soft foam padding. The units themselves are essentially a pair of die-cast black metal boxes about an inch and a half square by approximately an inch and a quarter deep, with two neatly protruding insulated cables and your chosen terminations at the end. I chose banana as I use spade terminations on my speaker cables so the units would connect using the unused banana ‘socket’ in the binding post.

Although I don’t know what is actually inside the Connected Fidelity RF Blockers the company say that they are entirely passive and that they have no effect on impedance or other speaker/amplifier characteristics. They do say that all speakers and amps are (obviously) designed and built differently and that most will benefit from their use, though their stament on their website suggests that this is a case of Your Mileage May Vary. Connected Fidelity also suggest that whatever the type of amplifier (A, A/B, D) or cables you use they will work, though they do say that they are not usable with active loudspeakers. I do like this specific quote from the maker’s website: “The Connected-Fidelity™ RF Blocker is based on sound electronics principles. There is no ‘Angel Dust’ used in this product!”

To be fair, there is probably not much more that I can say without sight of the internal circuitry, but I’m no electronics engineer anyway. However, if the units internals are as well presented as the external construction then I’m sure they will be put together well. Certainly, I experienced no untoward issue and I’d expect, if only because I disconnected and reconnected so often as part of my review process, that these small boxes have had more abuse than most might subject them to and they have survived my rough handling. Of course, what we really want to know is do they work, so onwards to sound quality. 


As per my introduction, I really didn’t know what to expect and was, frankly, more than a little sceptical of the claims made about what these units might do. I did discuss these prior to using them and understood these are not a product that always has a huge, instantly noticeable effect and that they can be rig dependant – at least to some extent. In essence, I was fully prepared for zero impact – indeed, it may well be said that I was actually expecting zero impact.

However, I was shocked and I’d have to say my initial reservations were swept away! I will say straight away (big intake of air and audible wow!) I really did have my expectations proved wrong! I knew almost instantly, literally before the end of the first song on the first album that something positive was happening here. To emphasise the point – I didn’t expect anything, my expectations were seriously low but I hoped I’d at least hear something, though in truth I found this hugely unlikely.  I am no electronics engineer and make no claims to understand how these little boxes work, but work they do in my rig!

So exactly what did I hear? Or not hear? As I’ve already mentioned, I knew that these small units were making a difference right from the first few minutes, but as per my usual routine, I lived with them for some time before really making any final judgement.

I noticed that bass was tighter and the top-end had what I’d describe as more ‘sparkle’. Everything seemed cleaner and the presentation better defined. I would add, I didn’t feel I’d lost anything and nor did I notice any fatiguing edges. The soundstage had more depth and width, there was a better separation between instruments and everything had more ‘attack’.

Easy to say, but everything I listened to simply felt more real.

There were several albums that really stood out – Chris Rea’s Road to Hell had simply been transformed, especially the rhythm and pace which seemed so much more driven (pardon the pun).

I continued to do as I usually do, retro testing, playing the same tracks repeatedly with units in and units out. I tried different days, different times and of course different music. I heard albums I’ve been listening to for over forty years that simply left me breathless, Joni Mitchell’s Hejira and Hissing of Summer Lawns in particular. I tried streaming both those albums and my ripped version as well as playing silver disc (CD) and no matter which version I found that the album I’d loved, despite what I had thought before to be a slightly muffled and overly warm presentation in places, was simply not anymore! Perhaps not the best mastered or recorded albums I have, but I now find these albums have gained a much greater respect from me and that is thanks to these small metal boxes!

I’m sure there will be naysayers, there usually are regarding products of this nature.  All I can suggest is try them. I love what they did to the sound quality of my system. I thought I’d probably have to spend ‘big’ to further improve the overall sound quality of my set-up – well it seems that is not the case and I’m certainly not complaining. I know my set-up was already revealing, but these little boxes offered an instant and obvious lift without any kind of detrimental effect that I can discern, even after at least a hundred plus hours of listening.  All the usual reviewer expletives apply, we’ve all read the darker blacks and more prescient detail type hyperbole. I’m not even going to go there, these little boxes work spectacularly well in my rig and opened the soundstage further, more micro detail, improved soundstage and instrument separation, in essence, everything just felt more real.  I’m not even going to list all the albums, I listened to so many and everything was, well, just improved. It was that simple! 


I’m not going to write a long conclusion, that seems like overkill now. My findings are simple and I think I’ve probably sung the praises of these little RF Blockers enough already. For any that have skipped straight to the conclusion, I love what these little units did, or rather do for my rig. In my rig, they do what it said on the tin and I simply can’t argue with the manufacturer who was open enough to even say, if they don’t work for you just send them back. The effect was pretty much instant, it really didn’t take me long to decide I really liked what they do. I removed and replaced them in my rig numerous times and with lots of different music and at different times of day. They were thoroughly tested and I am awarding them my ultimate accolade – I do not want to send these RF Blockers back. I’ve looked in my wallet and even with a Yorkshire man’s grimace I’ve decided these RF Blockers are staying where they are. Well made and neat looking. I think given the price to sound formulae, for me they are an easy pass and gold star to boot.


Build Quality:

Simple, neat and well made.  There are similar products on the market encased in plastic boxes, these are solid little units made from a die cast metal, the cables are finished neatly and terminations look to be good quality gold plated fittings.

Sound Quality:

Once I had installed these units in my rig I simply can’t sing their praise enough. I noticed an obvious lift in clarity, micro detail, sound stage etc. and noticed no detrimental effect over protracted listening. I didn’t gain at the cost of something else, gains are across the whole frequency range. Everything just felt more real. 

Value for Money:

Based on my findings I’ve opened my wallet to have a look… I think for the gain I achieved in my system these units are worth every penny. I say try them, I’m told they can be system dependant, but I love them.

We Loved: 

Easy to fit

Look neat and are well made

I gained an instant lift to sound quality

Good value

We Didn’t Love so much:

I’m told these units can be system dependant to some extent (worth the effort to try if you can though)


£249 inc VAT

Elevator Pitch Review: I was sceptical, I didn’t expect any effect and was shocked by how effective these small units are. Well made, easy to fit and given the lift in sound quality I experienced well worth a try. They may be system dependant, but if readers get the same sort of sound quality improvement that I did I’m struggling to work out what is not to like!

Supplied By Connected-Fidelity

Ken Stokes






Review Equipment: Roksan Caspian M2 CD player (transport only), MacBook Pro using Audirvana for ripped uncompressed flac files and Qobuz Studio for streamed. Benchmark Dac3 Pre / Dac to Nord NC500 MK2 spec’ Dual Mono Power Amp, Vienna Acoustics Beethoven Baby Grand SE Speakers, Chord EpicX speaker cable, Tellurium Q Black XLR, Chord Epic digital coax and Chord Epic USB, mains – Belden DIY Screened Mains Cables.

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