Audiolab's DC Block 6 wants to help rid your whole system of noise

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Clean up your mains for up to six separate hi-fi components

Audiolab Power Block 6
(Image credit: Audiolab)

Audiolab has launched the DC Block 6, a six-way power strip that provides individually isolated mains for your entire hi-fi. 

Designed to improve the quality of the AC electricity consumers use to power their sound systems, the DC Block 6 is the same width as an Audiolab source and amp components for simplified stacking and cable runs.

At the front is an OLED voltmeter, while around the back are six C13 IEC outlets. By connecting these outlets to the AC mains input of each audio component in your hi-fi and running a single IEC cable to connect the DC Block 6 to a standard power outlet, Audiolab says the device will remove RFI/EMI and banish ‘DC on the mains’.

Audiolab Power Block 6

(Image credit: Audiolab)

‘DC on the mains’ is a problem that arises when devices on an AC circuit act as an asymmetrical load causing the voltage waveform to become offset and resulting in DC voltage on an AC supply.

Audiolab warns that many of the AC transformers commonly used in home audio equipment aren't able to tolerate the presence of significant levels of DC voltage without being compromised, affecting sonic performance and even causing audible mechanical vibration. The company claims that the Block 6 can correct DC offset and rebalance the mains sine wave by blocking DC voltage found within the AC mains supply.

Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI) are separate noise issues arising from electromagnetic radiation produced by electronic devices. EMI refers to short-range interference caused by high-frequency emissions, such as those from switch mode power supplies in domestic appliances. Meanwhile, RFI is longer wavelength interference from external sources such as phones and Wi-Fi networks.

Audiolab Power Block 6

(Image credit: Audiolab)

By addressing all these issues, Audiolab says that the DC Block 6 can helps audio components perform at their best, reducing a system's noise floor.

The Audiolab DC Block 6 all-in-one DC blocker and mains filter is available in black or silver from November, priced at £349 (around $395/AU$628). It comes with six IEC C14 to C13 cables to connect to system components and a cable to plug into the mains.

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Mary Stone

Mary is a staff writer at What Hi-Fi? and has over a decade of experience working as a sound engineer mixing live events, music and theatre. Her mixing credits include productions at The National Theatre and in the West End, as well as original musicals composed by Mark Knopfler, Tori Amos, Guy Chambers, Howard Goodall and Dan Gillespie Sells. 

7 Comments Comment from the forums
  • Combat
    That's mighty fine snake oil you have there!

    But if it helps reduce the noise from my fridge, washing machine and dish Washer I'll take three please!
    Reply
  • Symples
    This will go well with my £4200 fuse...

    3993
    Reply
  • dangerousdaveferrari
    Combat said:
    That's mighty fine snake oil you have there!

    But if it helps reduce the noise from my fridge, washing machine and dish Washer I'll take three please!

    There is a lot of snake oil in hifi but DC on the mains is real. Plug your amp into a 4-way mains gang lead and plug a lamp into the same 4-way and by the nature of physics, your transformer will pick it up. Doesn't require David Blaine or Mystic Meg to make that happen, just electro magnetics. Transformers hum and buzz as an effect of DC on the mains and it is noticeable.

    Admittedly, it's quite a basic circuit to filter it and I've obviously never auditioned this audiolab unit but if your transformer is affected by DC, which it almost certainly will be if you have a fridge, washing machine and dish washer on your home mains, and if this circuit is correct (which I'm sure it would be), it's not snake oil to suggest that it would work. It's physics.
    Reply
  • Combat
    dangerousdaveferrari said:
    There is a lot of snake oil in hifi but DC on the mains is real. Plug your amp into a 4-way mains gang lead and plug a lamp into the same 4-way and by the nature of physics, your transformer will pick it up. Doesn't require David Blaine or Mystic Meg to make that happen, just electro magnetics. Transformers hum and buzz as an effect of DC on the mains and it is noticeable.

    Admittedly, it's quite a basic circuit to filter it and I've obviously never auditioned this audiolab unit but if your transformer is affected by DC, which it almost certainly will be if you have a fridge, washing machine and dish washer on your home mains, and if this circuit is correct (which I'm sure it would be), it's not snake oil to suggest that it would work. It's physics.

    I don't deny that you can back up most HiFi claims with scientific explanations of why it helps. There must be a million things that would measurably change your listening experience. However, how much of a difference would this really make?

    For example, I'm sitting two feet from my computer monitor with a set of active speakers either side (Triangle Twin AIO - awarded five stars by this publication last week) . I have to put my head within six inches of the speakers when no music is playing to hear anything else from them. All the while I'm hearing other louder sounds in my room such as my occasionally creaking chair, the fan on my laptop, a car outside, the wind outside and even the inhale and exhale from my nostrils. Will this Audiolab product create absolute silence in my room in order for me to enjoy the music and only the music? No. Will in reduce the ambient noise at all? Probably not but even if it does is it really going to help my enjoy my music more? Maybe in my head it does. Because it's snake oil.
    Reply
  • Friesiansam
    Will the wonders of snake oil never cease?
    Reply
  • dangerousdaveferrari
    I’m replying out of courtesy to explain with rationality and fact, rather than try and convince. I think a lot of people would also make the same assumption so please don’t take offence but I think youre missing the point of a DC filter and what it actually (not supposedly) does.

    You don’t ‘hear’ DC - there is no audible noise, like static or white noise. Maybe you’ll hear the transform hum a little bit that’s a vibration that you’re hearing, caused by DC.

    However, DC on the mains will definitely affect a transformers performance and it will, in many cases cause a transformer to hum or vibrate. A real phenomenon and a real factor in the ability of a transformer to operate to optimum capability - which is important in audio systems.

    DC doesn’t make your cone hum. It doesn’t hiss and it doesn’t whistle, so no matter how close you get, you won’t hear it.

    However, remove DC from your mains and your transformer will performer better.

    Will it audibly affect your particular speakers? I am not saying, so at all. But it’s easy to test.

    Would such a circuit affect ambient noise in your room? - absolutely not, unless your transformer is humming and you can hear it! A DC filter would stop that, for sure.

    The science absolutely guarantees that removing DC improves a transformers ability to do its job, and therefore it is very likely to make an audible difference in audio equipment. I bet your speakers were designed on a clean mains supply, for sure.

    Will it sound ‘Better’? That’s subjective and in your head, I agree.

    But will it make a difference? - Yes.

    And is that actually measurable? - Yes.

    And is that good for the whole electronic’s design, function and purpose? - Yes.

    Not to worry though, I’m not selling it and it’s probably not for tabletop speakers. But proven principle of physics isn’t snake oil and the principle of removing DC from an AC power supply is known to affect audio equipment and I suppose that’s all I’m trying to clarify.

    And in even shorter summary - that’s why I’ll be inclined to try one in my system to see if it can help improve performance.
    Reply
  • Symples
    I've no doubt that these devices have a measurable difference (in the lab)

    But I would question on how much an audio difference (improvement?) they make.
    Could we actually hear that difference.

    There is a very slight hum coming from my turntable. I only know this, as when I approach my hifi to change records. I can hear it. I've never noticed it when playing music.

    Should I spend money or time investigating or eliminating it?
    Moot question, people :)

    My problem with these devices is not that they do not work. I'm sure they do.
    My question is how much a audio difference do they make?

    Many many years ago. I replaced my cheap bell wire with a QED79 cable. Connected it up to my Pioneer SA608 and Kef Celeste III speakers. Didn't hear a difference.

    Now I am not saying there wasn't a difference, but I didn't hear it.

    This had made me very skeptical about some hifi claims (don't get me started on digital cables!)

    My advice:
    As many others have said, "Try before you buy."
    Reply