NAIM HICAP DR: current hum

Hi everyone, please I would like your opinion. I have a HICAP DR from which, after about an hour of use, I hear a slight current hum. Is it normal? Thank youn outline about what this category is all about

Probably transformer hum.
Some do, some don’t:
when I had two HiCap DR’s - one had a hum, the other didn’t.

IFI have a nice little gizmo (the DC Blocker, pic below) that may help to reduce the hum if it’s noticeable from a distance. Worked on my ‘hummy’ SuperCap 2. Didn’t remove it, but the hum was considerably reduced.

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As @steviebee says. They do work well, used them on my humming NAP 250s.


It was you DG who brought IFI to my notice, so thanks! For the comparatively cheap price, it’s a bargain on my SuperCap.


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Only a slight hum, and only after half an hour? You’re lucky.

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Mine hums on and off through the week. It has a particular fondness for Sunday morning. I’ve stopped giving it any brain space as it has zero impact on the music.

Yes, in fact, sometimes the hum is louder, other times less so and sometimes you can’t hear it. Where is the DC Blocker positioned and how much does it cost?

The DC Blocker is £129 new. Can be found cheaper (seen £99). There’s a DC Blocker+ (for power amps etc, if I understood the blurb) for £20 more.

It sits between the power cable plug and the HCDR power socket.

If the hum is noticeable/annoying when sitting at usual listening distances, or at night when it’s quiet (my situation), it may be worth giving it a try.

maybe I should buy a mains conditioner so I can also add it to the other hifi components (amplifier and CD player). in this case which one do you recommend for Naim? Thank you

Yes. Do not worry about it.

Cost = £0-00.

Worrying about it.

Cost £???-??.

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The direct answer to the first question is a little box to plug into the Hicap like the IFI mentioned. Some say that they affect sound quality, some say they don’t. If the hum is from the Hicap itself, trying one may be the cheapest option.

Whether that helps or not, if the hum is dependent on time of day, then it may well be a problem caused by something else on the same power supply.

I am no fan of mains conditioners in general, but some here have specific examples that they swear by and that I have not heard. Otoh…

Where possible, the surprisingly cheap (in comparison) option that many of us endorse is to get an electrician to run a dedicated supply from the meter (via Henly box) to dedicated and unswitched sockets. Mine cost £600 in total - not too different from one Naim Powerline.

Add a star-earthed supply like the Grahams Hydra and you have probably gone as far as almost all of here at fixing any mains issues. Doing all that for mains power was a noticeable SQ upgrade for me, even though I was not trying to address a hum issue.

I use the ifi thingy and 4 headed hydra on my 2 hicaps, 555psu and napsc. Definitely reduces any noise. Cant say it detracted from the sound quality.


so for Hicap DR is the 500 watt DC Blocker or the 1000 plus ok? Thank you

I would’ve thought the DC Blocker basic would be fine. It’s ‘only’ a HiCap.

I bought a + DCB for my 300DR PS. Didn’t do much so I’m going to experiment a bit. It’s currently on my SuperCap, where it’s as effective as the non-+.

The £99 one is what i use on hicaps and cd555psu.

It’s an Hicap DR

I know, didnt bother typing DR as I can’t see the DR adding a problem with a non + DB. But, the ‘upgrade’ to DB+ is ‘only’ £20. You pays yer money and takes yer choice…or not. Depends if the hum is so audible it bothers you enough to try one - or not.

Exactly. My ifi things for £99 are used on hicap drs and a 555dr, for what its worth.

All transformers hum there’s not much you can do to stop it apart from switching it off. My hi cap used to hum so much so I opened it up and lifted the transformer off its mount. The material used to isolate the transformer was squashed so thin it may as well not have been there. So I replaced it and the stuff under the large washer that goes on top. No more hum


What was the material?

Where did you purchase it from?