Lost bass with HicapDR upgrade

I have upgraded recently my SN2 with Hicap Dr which is 5-6 years old. The Hicap gave me incredibly more open sound, soundstage and details which was more than I expected, however my bass response has significantly dropped and now the midrange is dominant while the bass is more hollow. I have read that the Hicap gives more control to the bass but I don’t experience only more control but significant bass loss. What is interesting is the that the first 2 days the bass was very punchy and tight and then suddenly it disappeared. Has someone experienced anything similar?

Give it time. I thought this when I first connected mine. It took a while for it to settle in.

Out of curiosity, I decided to try my SN2 without it this morning to see if I could tell the difference. One part of me was thinking I wouldn’t, or that I’d prefer it without it. Well… it took two tracks and what stood out was it felt flat, the soundstage diminished and lost a bit of the weight, control and warmth in the lower tones. The soundstage and imaging really did take a hit. It just didn’t feel right. I couldn’t reconnect it fast enough!

Anyway, I’ll repay the advice I was given by @Mr.M when I first got mine… don’t be tempted to disconnect then reconnect, let it settle in for a while (weeks not days). I’m sure it will all come together given time to settle in.


Mmm… it does seem strange to me that the bass has gone AWOL. Maybe the HiCap is revealing a weakness elsewhere. How are you connected up? Are you using NAC A5 speaker cables properly soldered with Naim’s SA8 plugs at the amplifier end?

In my experience with the HiCap so far - everything sounds richer, effortless and more organic. Bass is deep yet tight in a coherent way with the rest of the presentation. I did the same as Toonartist and took mine out, it lasted no more than ten minutes. HiCap DR went straight back in without any hesitation


Here I am, as with any Naim PSU it’s important to position it correctly and to pay particular attention to the SNAIC cabling between it and your NAIT.
You ideally want the cabling hanging loose and not looping on itself or touching other cabling especially mains or speaker cables. If you can keep them off the floor that’s helpful but not essential as it would be with the more sensitive Burndy type cables.
It’s also worth bearing in mind what the HiCap is actually doing which is powering the Preamp section on the NAIT primarily, so keep the HiCap as far from the things its delivering power to as cabling and layout allows.
If you want a stacking order the HiCap is usually best sited at the bottom closest to the floor and I’d tend to put it on the right hand side to put some space between it and the electronics in the NAIT, you often see people putting them in the middle of a shelf, this is mainly for asthetic purposes rather than being the optimal place to site it.
If it’s humming and they all do a little, some a bit more, this is normal and characteristic of a torodial power supply, it’s what allows it to provide very stable and clean DC power which is what your NAIT requires from it and what passes across the SNAIC cabling.
You may find you need to experiment with moving it very slightly till it is interacting and resonating against the thing its sitting on less, if it’s sat on a highly resonant material or on a suspended floor you may need to put in a bit more effort to isolate it and minimise hum.
If you can, keep everything as level as possible, if everything is sloping off 4/5mm it’ll sound different.
Once you get it where it’s happy depending on the age of the HiCap and NAIT do give it time to settle in, usually a few weeks is an accepted period of time and it will change subtlely over a much longer period of time.
You may also need to experiment with speaker positioning as the soundstage will alter when adding a PSU like the HiCap. I recently spent a solid couple of days just moving and listening to my speakers at different spacing apart, distance from wall and toe in.
Having had them in roughly the same place for years they’re now closer together and further in from the wall behind them and sound a lot better as a result, the only thing having changed being the speaker location in that case.
You’ve little to lose from spending a few hours trying out different speaker positions and may be surprised.
A final reminder, these boxes are usually best left turned on and left on all the time. You only really need to turn them off if you’re away for more than a few days or there’s lightning in the area.
You can switch them on and off every day should you wish but over time this will wear the components measurably faster than if you’d left them on all the time, shortening the time period between servicing which is usually expected somewhere between 10-15 years from new and the higher spec boxes like a 555PS have the shorter recommended service intervals.
If you power the system off/on, the HiCap is the first on and last off regardless of what else is connected like streamers, CD player etc, do stick to that to avoid any unneccesary damage to your kit and of course never unplug the SNAIC cables unless it’s all powered off and has been left a few minutes for the capacitors to disipate, don’t switch them off and then unplug things right away as there is a fair bit of residual energy stored in the power supplies even with no incoming AC.
Hope that all helps.


I’m using Chord Epic Twin 2X3 meters. Usually they provide very warm and rich sound. I also thought the HiCap may reveal something weaker in my system. The only thing I can think of is my Innuos Streamer. It’s connected via Chord Epic digital cable to my nDAC. It can be the new weakest link in my system, however I’m not 100% sure. As others suggested I will wait for about a month or a couple of weeks to see how the sound will change.

In addition, I also experience richer, effortless sounds except for the bass. Anything else is superb!

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What speakers are you using and how are they setup in the listening room?
I’d not completely discount needing to move them about a bit to see what difference that makes as well.
Weak bass is certainly not characteristic of a SN2 + HiCap DR.
If you take the HiCap out does the bass come back as you’d expect it to?

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Thank you for your detailed opinion and pieces of advice!

The SNAIC cables are hanging loose however they have contact with one speaker cable and one mains and touch the floor. I have positioned my HiCap furthest away from any other equipment and near the floor. Yes, my HiCap is humming. I can try to add an isolation wooden platform with SoundCare legs beneath it since I don’t have a special hi-fi rack. I’m using normal living room rack and have put wooden platforms under most of my equipment (except the HiCap).

I have been running the HiCap for a week so this might be a short period of time. What I was also thinking is that the HiCap has very huge capacitors. When a capacitor is fully loaded with electricity and has been working on for a while the sound usually improves. This might be an explanation why the HiCap might need more time to settle in.

I’m using Monitor Audio Gold 200 5G which usually provide a lot of bass. They are about 70-80 cm away from the wall and about 210 cm from each other and I’m listening from around a 240 cm distance. I started experimenting putting them a bit back to the wall and I think the sounds gets warmer and warmer but I want to do it incrementally since the HiCap might continue changing it’s sound signature.

I haven’t tried taking the HiCap out. I might try it ass well. Good point.

You need to “untouch” those SNAICs really, that won’t help at all.
The caps do need time to energise, that takes a short amount of time from them being connected cold, within half an hour or there abouts they should be running at their normal operational tolerances.
As your HiCap is a few years old it should be well run in and should be running as well as you would expect one to, the run in is with a new unit that needs to settle in, that’s not the case here.
I’m not familiar with your speakers but certainly the closer they are to the wall behind them the fuller the bass will become but you get to a point where it can get a bit bloated and boomy and lose definition. Trial and error required in that instance.
I’d certainly power it all off and leave it for a good 10-15 minutes, put the jumper connector on the back of NAIT and power it up without the HiCap and do a quick comparison, just leave a little time between turning things off and recabling and back on again as I explained earlier.
The fact you have cables touching your speaker and mains cabling is not good and I’d get the cable dressing sorted best you can as well.

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The speakers have two bass reflex ports on the back and it is typical for them to have stronger bass the further backed they are pulled. But yes, there is a risk of the bass to gets boomy and to loose some of the depth of the soundstage. I know the burn in period is valid mainly for brand new equipment, but I’ve heard that if a given equipment is not being used for some period of time it might again need some time to settle in. My device has been transported, then I didn’t use it right away. It might not have been used for at least a month. I’ll try how the sound is without the HiCap.

I think you have a few things here to try and hopefully once you’ve gone through the list it’ll at least be better if not resolved entirely.

  1. Sort out the cabling, move the HiCap if necessary to avoid the SNAICS touching any other cables, also avoid them looping on themselves, it may seem a trivial aspect but usually it isn’t in the case of these PSU’s. If they do have to touch the floor which I expect they will do that’s not the end of the world, main thing here is avoiding them touching other cabling in the system or AC mains cables from things nearby.
  2. Have a listen without the HiCap, if it’s a whole lot better, there may be a chance the HiCap needs a service.
  3. Move the speakers about and see if you can find a location that works well for you.
  4. Leave it to settle, it shouldn’t need a whole lot of time to settle down given its age, if it was new or almost new I’d say run it a month or more and report back, even if it’s been moved or not used for a while it’s basically run in at that age and just needs to run enough to get up to usual operational tolerances which it should do within 30-45 minutes.
  5. Mains, I’d confirm what circuit your Naim kit is sitting on, is there anything else on that circuit that could be adding noise to the system. If it’s on a ring main that could be any number of things like TV’s, Fridges and so on. Ideally it needs to be powered of it’s own mains radial circuit to give it a as clean a path between the kit and the mains coming in from the grid. If you don’t have it, give it some thought and factor for it later on as it does make a difference and will help settle the system down, excessively noisy power supplies would usually indicate excess DC leaking on to the incoming AC to the power supplies coming from things like TV’s or Fridges as examples. Check the circuit it’s sitting on anyway and if you can unplug other things on that circuit as you retest and avoid it sitting on the same circuit as things like TV’s washing machines or fridges.
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Just had exactly the same problem when replacing a HiCap with a DR version for my NAC282.

Alastair (@ Signals) mentioned about cables free hanging etc. and so it proved.

Make sure the SNAICS don’t touch the mains cables - I think (unless the HiCap is defective) this is where your problem lies.

Good luck.



Yes, good shout. I agree with having the cables as freely spaced and hanging away as is physically possible. Especially power and signal cables.

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Sorry I wasn’t aware that the Burndy cable could not be looped. On my hifi rack that seems to be the easiest and least stress causing way to install it as the preamp and SUPERCAP aren’t too far apart.

I tested running SN2 without a HiCap. The bass behaviour was the same. At least I now know the HiCap is not the reason for this strange behaviour! Also some of the openess and details disappeared and I affirmed that I like my system better with the HiCap on.

I also tried moving the SNAICs away from the other cables. The result was the same but since the HiCap and the SNAICs turned out to not be the reason it’s normal.

As for the mains power - I don’t think this would be the problem. I use the same circuit as before and have experienced good bass with it. I agree that a separate curcuit would give better results and cleaner current.

During this tests I recalled that 4 days ago I installed a brand new PowerLine Lite power cable to my SN2. Previously I was using the normal stock cable that usually comes with Nait 5si for example. Could it be that the PowerLine is not broken in and it would take some time?

Speaker cables. I’m 100% convinced.

The Chord Epic Twin are the cables that provided me with the fullest and richest bass from all speaker cables I’ve tried. I’ve been using them for more than an year. Why do you think they might be problematic in my case?

The reason i think. 1 - they are too short. The other is i would use NAC A5 soldered correctly using the the Naim SA8 plugs at the amplifier end done and made up by a dealer that really knows their onions. I believe this is to be your problem with your sound quality issues at present. I’ve used Chord cables in the past and it is no match to Naim’s own. NAC A5 gives plenty of bass. There is no need to fault the rest of your kit.

@corsuse have you checked over the back to see if the HiCap cables are hanging free? I can tell straight away when something is amiss.
Also don’t tighten the collar nuts, leave undone and pull back SNAIC cables from being 100% pushed fully home by 1mm at both the Hicap and the Supernait and then let me know your thoughts.
Make sure power kettle lead or powerline whatever you use is pushed fully home, these require a solid push past the point of first resistance. :+1:t2:

Not good advice for anything carrying power. You can only do this with signal leads.