NAC282 Dual Hicaps

Having a second hicap on a 282 might break the principles of star-earthing, but connecting a Supercap to a 282 using two Snaics creates a ground loop because each Snaic provides it’s own path to ground.

When connecting to a 282, here are the connections used on the Supercap

Here are the sockets the Supercap connects to on the 282

Socket 1 on the Supercap connects to “Upgrade 1” on the 282. Socket 2 on the Supercap connects to “Upgrade 2” on the 282. Note both Supercap sockets include a 0v (or ground) connection. We know that the “Upgrade 1” socket must include a ground connection because that’s where a Hicap would connect to in the case of a single Hicap. It must also be the case that the “Uograde 2” socket must also include a ground connection because that’s the socket a 2nd Hicap would connect to and the 2nd Hicap wouldn’t work if it didn’t include a ground connection back to the 282. Just for confirmation though, here’s the wiring of the “Upgrade 2” socket.

(Green wire is the ground connection.

Is this dual connection for the ground path a serious issue? Well, here’s what the Forum FAQ on the the use of DIN plugs says about ground loops:

Many manufacturers point to the great trouble they take to “star ground” everything. Sadly, this is all wasted when you connect your system together with RCA-plugged cables. Why?

When you connect, for instance, a CD player to a preamp with RCA-plugged cable, you automatically have two separate ground wires - the left and right shields going between them. This creates a ground loop, which degrades the musical performance dramatically, and negates any efforts that were taken to ground the internal circuits properly.

If you were to connect these same two components together with DIN-plugged Naim interconnects, you would have only ONE cable with only ONE ground shield surrounding both the left and right signal wires. Hence, only one ground path for each connection and no ground loop.

So there does appear to be a performance compromise here when using two Snaic connections from Supercap to 282. From my own findings comparing a HCDR to a freshly recapped Supercap-2, it was like the Supercap was two steps forward, sonically, but 1 step back musically. As impressive as it sounded, I just wasn’t getting the raw emotional involvement with the Supercap that I was with the Hicap. That’s why I did a bit of digging into the above. So after a bit of thought I arranged things so the ground loop didn’t exist, and bam, there it was, the involvement was back.


Hi Allan - Yes, as you show in your post, there are two paths for signal ground (0v) connection between 282 and SC when using two Snaics. Loop area is minimised by keeping them close together which tends to happen naturally due to the socket layout on both products. I can see another approach could be taken but this would be outside the forum AUP. Can I ask what you did (as long as it’s not cable mods !) ?

Looking in the manual for connecting up HCs and SCs, no mention is made of using 2 HCs. That I can see anyway.
With the 4 pin “link 2” plug/paddle thing removed, the manual only shows a SC being connected.

Hi James, no modifications were made to the boxes, beyond that I cannot say more. Suffice it to say though, the difference was quite noticeable.

The way I quickly evaluate “musicality” or “involvement”, if you like, is to try and ignore the sound produced in the room and try and recognise how easy it is to just be conscious of, and be listening to, the music that is replicated in the head. Difficult to describe unfortunately. I stumbled on this technique when I realised that the most involving and sublime musical experiences come about not from listening directly to the sound that is formed at the other end of the room over where the speakers are, no matter how impressive, but when I’m not actually conscious of the physical sound, instead I’m simply involved with, and only aware of, the music that’s dancing around inside my head.

Thinking about it more, it’s a bit like Linn’s Tune Dem technique, the core of which involves “silent repetition”. Which I never really got when I came across it as it involves a conscious attempt to repeat the sounds of individual instruments and voices in the head, whereas my technique is similar but I’d describe it more as “sub-conscious replication” and it’s more about the music as a whole than individual strands.

These sort of techniques are probably a bit artificial as they don’t really reflect real-world / long-term listening, but I’ve found it quite a sensitive and quite reliable test. Even when an upgrade produces misleadingly “impressive” sounding results. The ground-loop test, for example, was quite an easy spot and I knew very quickly and instinctively when it was resolved.

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Hi if you look in the document ‘Naim connection guide’ which you can download as a pdf it gives you most connection permutations from the NAC552 to the NAC 152. It’s a really useful document.

Very interesting… Understood :slightly_smiling_face:

Yes, I never really got on with the Tunedem method. I see where Linn are coming from but I think we tend to do that naturally anyway in a less contrived way. I’m curious as to the different ways we listen - not sure if you’ve you’ve seen this

Going slightly OT so better get back to the Dual Hicaps thread…


Hi I also meant to add Naim also indicate the upgrade potential of dual Hicaps on the 282 on their website.

Nac 82 manual has the diags for connection of either.

'Tiz a bit odd.!


And clearly can be done. Perhaps they think that connecting via 2 snaics is the same whether via SC or HC ( it is)

The earthing theories are all very well but it’s the reality at your ears that matters. I definitely felt the 2nd Hicap DR was worthwhile on my 282. The SCDR is better but then again it’s more money and you are only utilising a fraction of its potential.
As a stepping stone to a 252, the SC does makes more sense…


Sorry, but electrical grounding theories are ‘reality’. What you perceive via yer own lugholes is highly subjective.

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definitely, to connect dual HiCaps or Supercap to NAC 282 + NAP 250DR which SNAIC cables are needed?

thanks and rgds,

282 > 2x SNAIC5 > Hicaps or Supercap > DIN4 to XLR > 250

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The SNAIC is supplied with the HiCap not with the Supercap, I think Naim charge around £180 per SNAIC so needs to be factored in with the SC.

Not wanting to cast nasturtiums but Mrs Bruss who is not the most discerning of listeners, has just wandered in to the study and said “it even sounds good in here” . The only thing I have changed is adding in the 2nd hicap.
Just sayin’.


That’s always a good sign!

All this talk of second HiCaps I may have to try one on my 282, I once tried two HC on my old 82 but returned to one as I didn’t notice much difference but the room then wasn’t the best layout.

Indeed, no argument over the nature of reality - but whether the benefits of having separate, independent power supplies to each channel outweighs any detrimental effect due to suboptimal earthing is absolutely a matter that is best determined by listening.

I haven’t tried 2 Hicaps on the 282, just single Hicap compared to a Supercap, but I actually think that although not perfect, the grounding arrangement for two Hicaps isn’t too bad. It doesn’t setup a ground loop in the way that having two Snaics between the 282 and a Supercap does. Not having heard the comparison, I can only speculate, but I’d hazard a guess and say that the Supercap will sound more impressive, two hicaps more “musical”.

@Richard.Dane. Is there a grounding issue with supercap and degradation of sound quality versus 2 HICAPS as far as Naim engineers and industry representatives know?

I may have missed a post from you whilst reviewing this thread and the other “does a power supply really make a difference”, thread…is there any evidence based on actual DATA that this supercap ground loop issue in reference is a concern or issue?

I am in the process of waiting for delivery of a supercap to test, and am just inquiring. I find it hard to believe that naim would design and release a product for so many years that has a grounding issue.

And yes, to all the Naimers out there, I already know, “only your ears can discern the difference”. Given that, I am referring to data that says yes or no as far as testing is concerned.


May have missed another giving answer but connection of 2xhicaps is covered on page 13 in the Naim connection guide.

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