Connected Fidelity AC-2K Balanced Supply

Introduction

We take our mains power supply for granted like all the utilities we have in the UK (gas, water, broadband, for example). You turn a light switch on and expect the light to work every time, no matter what. This might sound obvious, but when you think about it more seriously, there’s a hugely complex system called the National Grid working tirelessly 24/7 to keep our homes and industry running.

Like cables in HiFi, I took the quality of my mains seriously about 30 years ago. Russ Andrews lauded the virtues in the 1980s, and his principles still apply today. Many companies have adopted this approach too, and the choice on offer is now huge. Just go to any decent HiFi show or read any of the magazines, and mains products are prominent.

When I moved to my current home in the nineties, I couldn’t afford any major equipment upgrades initially, but I could upgrade my mains in my listening room with the help of an electrician friend. I had a second consumer unit added, separate from my main house supply unit to minimise interference from domestic appliances and lighting. A dedicated 30-amp feed from the new unit fed a silver-plated twin mains socket in my living room and a separate earth attached to an earth spike buried in my front garden. A HiFi friend laughed at me when I told him what I had done, as he wasn’t a believer. Undeterred I was delighted with resultant improvement in bass performance and sound staging.

I have since owned various good-quality mains blocks, leads, and a power conditioner. I am reviewing these products because I spoke with Michael Osborn from Connected Fidelity years ago and own some of his excellent audio kit. I purchased the superb Six-Star distribution block and Unity two power mains cable over a year ago, plugged directly into my dedicated wall socket. The combination has served me well since then, providing a solid and stable platform for my system to excel. Every time I have seen Michael since then, he has kept saying Why not try the balanced AC-2K power unit. So now I am.

I was sent the latest upgrade: the AC-2K Reference with WireWound technologies and the matching recommended mains lead, which has a C19 16A IEC to connect to the power unit. Michael offers a 40% discount on one of his cables when bought with the AC-2K, a very worthwhile saving.

This is a review of the newest Connected Fidelity AC-2K, their new ‘Reference with WireWound technologies’. It is a balanced power unit, and I’m using the Connected Fidelity Six-Star distribution unit and RF Blocker Gold filter array.

Design Features

The AC-2K balanced supply has a ‘perfect’ earth; that is, it’s effectively isolated from ground earth and offers very low impedance, helping achieve the low noise floor of balanced power.

AC-2K refers to Alternating Current (mains power conditioning), and the 2K signifies 2,000 VA (2.0 kVA) of power-handling capacity, which provides enough headroom to run sensitive source components as well as high-power amplifiers

Michael commented in conversation;

I know that dedicated earth points do offer a lower noise floor (been there myself), and I believe this is because of the lower impedance to earth.  I read a research article a few years ago which demonstrated that you must earth a considerable distance away (100+ Metres) from any other earth point, be it your home, or other home earths, to find a clean ‘uncontaminated’ earthing point. Otherwise, the earth cable will have a high impedance, and be picking up RF noise, unless screened and constructed from very thick copper!

Michael and his team are developing a dedicated isolation platform for the AC-2K range. Not launched yet; it will be a bamboo platform with ‘Float’ isolation pucks incorporated, for use on either carpet or solid floor (2 options).  He mentioned this because most people do not put the AC-2K on their rack, either because there is no room or because it’s too big/heavy. Placing it on the floor does not offer the best sound quality; isolating the AC-2K does increase fidelity in most situations.  I did manage to fit it on the bottom shelf of one of my racks, but I warn anyone interested in trying/buying one that at 16 kg it’s a solid weight, and you need to be careful handling it. I only just managed it.

Michael sent me an AC-2K with a 10V reduced output. He has found this option works best for most customers (better audio fidelity at times) when their incoming voltage rises above 245VAC. Quite common in many areas. When the UK voltage is between 220-245V, there’s no difference in sound quality we can hear.  When I attached the AC-2K to my mains, it did read 235V on average.

I received the black anodised version, and it looked very smart. Beautifully machined and constructed; the sockets and switches are all top-notch, and I’m assured the internal components are too. (I didn’t feel the need to poke inside) If readers are interested, Michael has white papers on the AC-2 K’s design philosophy. From what I’ve read about the issues that can arise, transformer buzz is common. In my early days of HiFi retail back in the 80s, a couple of highly regarded brands we sold occasionally displayed this problem. It never did this in the shop, but at the customer’s home I witnessed it, and it was sometimes tricky to cure. Back then, the issue was called “dirty mains”. Remember, electronic components weren’t always as advanced as they are today, and the myriad of mains power products was far smaller then. This is not a criticism of 40 years ago; there have been huge advancements in many electronic components now. Today our domestic and business environments are overflowing with additional RF interference from Wi-Fi and Bluetooth, to name just two. It’s a very complex world now.

Put simply, all we want to do is simply switch on our HiFi or AV system and relax, and that is precisely what I did!!

When listening to your music, if your brain is constantly analysing the equipment, the room acoustics, or even the music itself, it becomes a chore. Your system should give you pleasure akin to sitting on a tropical beach with a drink in your hand and chilling.

Performance

My time with the AC-2K Reference with WireWound technologies balanced power unit was a breath of fresh air. There were never any pops, clicks, buzzes, or hums coming through my speakers, and the backgrounds were inky black. It won’t cure faulty or poorly designed components, but it will certainly showcase your system. The biggest compliment I can make is that I just relaxed to my music. Clarity made listening to any recording a pleasure. The music breathed and had free rein to entertain me. My recent review of the Ortofon MC 50X and my use of my own Hana SL Mk2 proved this ability to excel.

As I suggested earlier, don’t underestimate the importance of your mains. With a product as good as the AC-2K Reference, with WireWound technologies and a balanced power unit, you won’t regret adding it to your system. If you can’t initially afford the asking price of £3260 then opt for the six-star distribution unit which is truly excellent and a must if you go for the AC-2K. Together, they are a natural fit and massively complement one another. The AC-2K made me realise what can be achieved if you push the boat out.

RF Blocker Gold Filter Array

Separately, Michael kindly sent me a set of RF Blocker Gold filter arrays to try out as well. The RF Blocker Gold is manufactured to high audiophile standards; all signal parts are cryogenically treated. High-quality electrical components are used, all housed in a die-cast aluminium box acting as a Faraday cage to ensure no additional RF interference enters the audio chain. DIP switches turn the 4 x RF filters on/off. An earthing connector is fitted to the case for those who wish to earth it.

Short attaching cables are multi-strand single crystal (UP-OCC) hybrid copper/silver construction. The connector options are spade, banana or bare wire ends. Suitable for use with all types of amplifiers (Class A, A/B, and D) and all types of loudspeakers, except active. They work well with passive sub-bass units powered via the loudspeaker terminals. Michael stated that they can be system-dependent and don’t work for everyone. I found they did.

They had that cumulative effect of allowing my system to free up the music, the same as the AC-2K and my six-star distribution unit. Details were amazingly clear and so enjoyable. I tried Chris Rea’s Down on the Beach album, and the intricate background details really shone through. I know the album well but hadn’t noticed those details before.

Overall

In conclusion, if you can afford or justify several thousand pounds on a power upgrade to your precious system, then DO IT!! You may find that adding a Six-Star distribution block alone is surprisingly good, but if you can try the AC-2K as well, bliss may await.

Pros

• A fit-and-forget product that works as designed
• Built to last a lifetime with top-notch components
• It’s as good an upgrade as any other system component and allows them to shine

Cons

• Expensive, but then quality is never cheap and you only have to buy it once