Any benefit use DC Blocker in system?

Hi, anyone use it on your system ? Any benefit ?


Generally the advice is not to use one if you can, but it depends on what the problem is that you are trying to solve. Do you hear transformer hum?

50+ hits for “dc blocker”:

And a current one here, different product but lots of good general advice:

The most used , from memory, is the Isol 8 dc blocker. Some threads on it.
You have the recent thread “Audiolab dc blocker “ too.


Is the search facility not working?

Most filtering I have used In my system gave me some changes that I liked, but most of them also made me loose something, like making the amp have be a little less dynamic.

So for me is a little hard to give an advise on filtering, most of the time the results are good but perfection will cost a lot and I do not think there is a perfect mains filter.

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That is a rather good one, I think. Solved the transformer hum in our previous house, but unfortunately not the new house. I suspect high voltage rather than DC offset causing the hum.

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Isol8 DC blocker doesn’t do any filtering.

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I have the Supra DC Blocker and have had it for years. Great upgrade in my system removing mechanical hum from the Naim transformers and also to my ears increase overall sound quality. There are two versions around. The long version with the empty “square” as in the picture is the newest updated one.

“The filter will not dampen any dynamics. When the sound is much cleaner and tighter after the filter is connected, sometimes listeners perceive the dynamics to be reduced. When there is a difference in music and sound reproduction that will remove parts not really belonging to the source, this is a quite common reaction. On the contrary, bringing down the noice from the equipment will undoubtedly increase dynamics and often substantially reduce the duration of e.g. a bass pulse. Now it will most likely be possible to hear every tone in the bass range, also from each tuned drum skin.”

  • Removes DC from AC mains - Silence noise floor substantially
  • Tighter bass reproduction - Outstanding beat from drums, bass and percussion
  • Reduces transformer hum - No irritating noise from the devices
  • Reduces power supply heat dissapation - May prolong life span
  • Filters up to 3.6 VDC - Added capacity for future demands
  • No dampened dynamics - Audible true dynamics
  • Correct reference voltage - Substantially reduced harshness from DAC chips
  • Made in Sweden! - According to Supra Cables No-Nonsense strategy
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I didn’t heard the transformer hum, so is it no need to use it ?


Some kinds of transformer hum can be cured by DC blockers, so it would be a thing to try if you had experienced hum. As for SQ effects, it may have none, good ones, or bad ones. Might depend on your system as well. See the post by Slamdam above, it did good things for his ears. I’m sure you find other posts if you search the forum for Supra DC Blocker - but eventually you’d have to try for yourself

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I use it. It reduces transformer hum in my system, but there is no other way for finding out except to try it. I have used another DC Blocker with apparently similar specs and it did nothing.

This one has no filter whatsoever so should not have any influence on SQ except the difference which may occur by using an additional power cable. Bear in mind that you cannot connect a Naim cable to it as this DC Blocker uses a different socket type.

I would not buy it if you do not have transformer hum or don’t mind it.

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