HRS Nimbus Spacers / Nimbus Couplers – Experience Reports

Update 2014 This was originally written in 2004 or 2005.

Originally, when HRS told us we should use Nimbus between our components and the HRS Isolation Bases, and that it helped the sound quite a bit because it helped provide a sink for chassis borne vibrations to be channeled into the large mass of the base. We were like ‘yeah. Right. Suuuuure it does.

I mean, weren’t gear manufacturers telling us about how they put so much effort in choosing the exact right feet for their gear, some even designing special feet for their gear, that their feet were the best possible feet ever for their gear?

So we played a lot with HRS Damping Plates, putting them on top of lots of things, but ignored the Nimbus. Completely.

For years we ignored them.

But one day we didn’t.

For a modest amount of money, $300 to $400, you get a set of three HRS Nimbus Spacer + Couplers feet, which experience has shown adds 30% to 70% improvement to the sound, in kind with what the $2000+ HRS Isolation Base under the component added.

And, except for the Audio Note M9 preamp [which has gazillion screws in the bottom of the chassis], it is simple as pie to slap 3 of these under a component and get a predictable, repeatable improvement in the sound.

We never looked back. Now everything is on Nimbus. Always.

CD Players, Transports, DACs

Audio Aero Prestige

The Audio Aero Prestige CD / SACD Player with built-in preamplifier has both a moving mechanical device (the transport) and a vacuum tube – both of which are known to be sensitive to the dehabilitating effects of harmful vibrations. The Prestige comes from the factory with 3 black diamond racing cones as feet – a tribute to the fact that the factory also pays attention to vibration control.

As we broke in the Prestige and listened to it improve day-by-day, we noticed a little but of an overhang, a little smearing of the notes together. Yes, we thought it could be just a little more tube-like sound than we expected, but after living with the EMM Labs / Meitner in the system for a year or so, we had grown used to a more accurate sound, a more delineated soundstage, and a little more detail with our music.

As the weeks went on, the kind of dim and aging light bulb over our heads flickered on and we thought “Hey, aren’t these symptoms we are hearing are awfully familiar, kind of like exactly similar to those associated with vibrations interfering with the equipment? Oh, and, wow, the Prestige is sitting out in front of the 6 feet tall woofers of our speakers, too….”. And then our light bulbs flickered out again.

But, putting their brief appearance to best use, we decided to use some Nimbuses instead of the Black Diamond Racing cones underneath the Prestige in order to better couple the player to the HRS M3 Isolation Base platform.

Here we have removed the cones and put the Nimbuses underneath the player, in the same positions where the cones had been – letting the heads of the screws that were still in place dent the Nimbuses.

The sound was radically changed for the better. The differences in the sonics between the 50% more expensive solid-state Meitner digital and the tube-based Prestige now became almost completely one of that between different design goals and choices. The Meitner: purity and transparency, the Prestige: analog-like dynamics and harmonics.

Obviously, letting the screw heads sit on the Nimbuses was kind of a kludge, so we later used double height Nimbuses, and positioned them under parts of the player different than that where the original feet were installed.


Here we see the a picture of this configuration. Noticed that we reattached the Black Diamond Racing cones so that Mike would not lose them in the sometime mess that visits our house once in a while.

We also have another blog post on our  experiences with the HRS Nimbuses and the Prestige.


Lamm L2 Reference Linestage tube power supply

There was a clarity and purity added with three of these under the L2 power supply – much better than a number of different cones we have tried. There was also an improvement in the depth and tonality of the bass.


Audio Note U.K. Kegon monoblocks

The 300B Kegon amplifiers benefited from the M3 Isolation Base, but not as much as we had anticipated or hoped for. It was then that we noticed that our Kegons, which are old and have been shipped all over the country and auditioned by many dealers and audiophiles, were ….wobbly. They rested on only 3 of the sweet little feet thingies.


So, what to do, what to do. Well, you can see what we did, we added 3 nimbuses under each Kegon (it looks like only two here, I know, but we have one under the front and two, side-by-side under the back. Bamm. That did it. Everything was tighter. The Kegons always grip the speaker with an iron (or is it silver) fist, but now there was much more space between the notes. The decay of each note was more precise and did not linger.


It was the significance of this result, the great improvement after putting the nimbuses between the HRS M3 and the amplifier, that prompted us to try the same thing under the Lamm ML2.1 amplifiers and the Audio Aero Prestige CD/SACD player – on which, it turned out, there was an even greater impact (to which I attribute the fact that the Kegons were already doing a pretty darn good job at the things that unwanted vibrations traditionally degrade).

[Update 2014] Lamm ML2 monoblocks, Lamm ML3 monoblocks, Audio Note Ongaku, Gaku-On, etc.

10 years later we put Nimbus under everything when we have them – and we have them about 98% of the time [sometimes Neli will send some out on demo, and not tell me… until I go hunting for another set and they are nowhere to be found. Audiophile wives. Huh.].

EDGE NL Reference amplifiers

We first came up with putting Nimbuses under the Reference ‘pyramid’ amps at the high-end audio show in Denver, RMAF 2005. Always on the lookout to eek every last bit of performance out of each component – the sputtering light bulbs, yes,, the same ones referred to earlier, above our heads were able to convince us to try this tweak and see if it helped any.


What it did was to even out the frequency response some. There was a little hump in the upper bass and a corresponding depression in the low mids and they seemed to even out some – and in the very large, undampened room at the show, this helped calm down the overall presentation of the music some which , of course, is always appreciated at a show.

Interestingly, at the show we only had 7 Nimbuses so one amp went limping…

Here we see an example. Most of the other feet are more centered on their Nimbus, but we haven’t noticed any ill effects with this being slightly off center. Then again we haven’t tried moving it so that it is completely on center and seeing what it sounds like either. At 220 lbs., we run out of steam after ana mazing short amount of time when it comes to doing something that requires moving them around in any way.

We also have a blog entry on our experiences with the HRS Nimbuses and the Edge NL Reference amplifiers.

HRS M3X Isolation Base Experience Reports

This experience report was originally written several years ago and is on part of the old Audio Federation website that we are abandoning. Originally written around 2004, we are updating it and posting it here to make it more accessible and, hopefully, more useful for people who are interested in what the HRS M3 and M3X platforms can do..

CD Players, Transports, DACs

Audio Aero Capitole Mk II

The player’s sound was significantly improved with the isolation base under it, especially the quality of the bass and midrange articulation and timbre. This is a pretty typical result.


Audio Aero Prestige

The player’s sound was significantly improved with the isolation base under it, especially the quality of the bass and midrange articulation and timbre. The radical improvement obtained by adding adding Nimbuses between the player and the Isolation Base is described below.

[Update] Audio Aero LaSource

The player’s sound was improved with the isolation base under it, especially the quality of the bass and midrange articulation and timbre. The radical improvement obtained by adding adding Nimbus / Couplers between the player and the Isolation Base, and making sure that the Black Diamond Racing cone feet that come with the player are suspended in air and not being used at all, is a critical requirement to make this player really live up to its significant potential, turning a kind of sweet yet muddy sound into a rich sound with lots and lots of resolution.

Audio Note U.K. 4.1x Balanced DAC

Similar to our experiences with the Lamm L2 preamp, we just do not have enough Isolation Bases to go round, and though this DAC has had a platform temporarily underneath it at various time – all I can remember is that there was a general nod in its direction that it improved things, but that the scarcity of platforms forced us to fairly soon thereafter move it to a higher profiles system for a series of demos. [Update 2014] We eventually got a boatload of the M3X Isolation Bases and, although never losing its harmonic richness and ‘rightness’, the bases always made sure that there was an evenness in resolution and detail across the frequency band. Similarly with the Audio Note DAC 5 Signature and Fifth Element DAC


This component experienced the least improvement of any component we have tried on a HRS. We do use a damping plate on top, which has some positive effect. We hope to try Nimbuses between the DAC and the Isolation Base soon to see if this is what is required to get the usual significant delta in performance we experience with other components (often the feet that a component comes with seem to negate a lot of the effects of the HRS).

We’ll let you know!

[Update 2014] In general, as we saw with this DAC and as EMM Labs built more and robust [and heavier] components, well-built solid-state gear usually shows noticeably less improvement than does tube gear or transports. That said, there is still improvement, and in a system that tends toward brightness, putting a platform and Nimbus Couplers under even robust solid-state gear can and usually, in our experience, does make a world of difference and often eliminates the brightness [i.e. brightness and especially hardness is often caused by insufficient resolution, which the Isolation Bases always help with].


Lamm L2 Tube Preamplifier

OK, confession time. We cannot afford to buy all the Isolation Bases that we want… I mean need… in order to put them under all of our components. I know that at one time we did have an HRS underneath this component – but it has been awhile. I remember it working as expected – but I am 99% certain that one or another of the two pieces associated with this preamp (it has a separate power supply) were not on an HRS. So we look forward to both being on a platform – hopefully soon when we get our gloss black MXR rack here.

[Update 2014] Whew! That was a long time ago as we have had our MXR here for a long time, and an SXR, and… We almost never use the Lamm L2 without a platform: it is tube-based and the chassis is somewhat thin and resonant. A prime candidate for HRS racks and platforms. More dynamics and more resolution and tightens up the bass. This is pretty typical behavior – HRS does this for all components, to some degree, linearizing their response: in both resolution and dynamics across the frequency spectrum. This predictability of HRS in many different situations makes it an obvious choice compared to other solutions which are unpredictable and can sometimes even be deleterious in various systems and circumstances.

[Update 2014] Audio Note M9 and M10 pre-amplifiers

These preamps are capable of generating extremely powerful near-real-world dynamics. The M3X Isolation Bases increase and tighten these dynamics, making the whole experience a rush, while at the same time revealing their truly significant resolution which is otherwise somewhat hard to hear out of these puppies when they are sitting on top of your standard equipment rack.

[Update 2014] EMM Labs PRE2 preamplifier

Solid-state and robustly built, the improvements here are similar, but not jaw-dropping, compared to the improvement one sees for tube-based preamps.


Edge Signature One monoblocks

A real but somewhat surreptitious improvement in clarity of the bass was observed.

Lamm ML1.1 Tube monoblocks

An amazing amount of clarity was added to the midrange and bass, making these amps sound much more controlled and even across the frequency spectrum.

Lamm ML2 Tube monoblocks

I am not sure we ever used these amps without the M3 Isolation Base – so the improvements over using another platform (the Acoustic Dreams is what we usually use – which is no slacker either and we’d put it up against any of the competition [at $350/platform]) we can only assume is the same significant increase we found with the Lamm ML1.1.

We did try putting different HRS feet, ones specifically for lighter weight components, on the front because the front of the Lamm is so much lighter than the rear. I personally did not hear much of a difference using these differently configured feet in the front, not to say there wasn’t any, but that it did not jump out at me.

When we put some Nimbuses between the amps and the Isolation Bases, however, it was one of those “now we’re talkin'” moments, which you can read more about [in the next post].

[Update 2014] Lamm ML3 monoblocks

This amps have so much to offer in terms of resolution, both harmonic and dynamic, that we have always used these on top of a M3X Isolation Base, and with Nimbus Couplers between the amps and the M3X. – just to milk as much performance as possible from them.


[Update 2014] Audio Note Kegon, Audio Note Ongaku, Audio Note Kegon Balanced, Audio Note GakuOn [etc].

In general, the behavior of the Isolation Bases under Audio Note amplifiers is about the same as for that under Lamm amplifiers, but perhaps only about 75% the overall impact, specially as you move up the line into the heavier components. With the 55lb Kegons, the impact is similar to that of the ML2 [i.e. massive]. The midrange and bass both tighten up significantly resulting in much more resolution at those frequencies. With the 80lb Ongaku, less so – same kind of improvement but at only 80% or so as important as putting one of these under a lighter amp.



Brinkmann Balance turntable

HRS makes a custom platform for the Brinkmann Balance turntable.

Before the Brinkmann we used the Acapella Fondato Silenzio platform. After using this platform under both the Walker Proscenium Gold Signature and the Brinkmann, both times on the top shelf of a maple Rix Rax Grand Hoodoo – we have found that the Fondato is not the best thing for turntables (it works quite well under CDs and tube DACs and preamps) and the turntable sounds better directly on the Rix Rax shelf.

When we put the custom HRS M3 Isolation Base underneath the Brinkmann, we finally started hearing what the table could do. Before it had sounded a little thin and tizzy, and we changed cartridges a few times trying to find an solution. But it turned out to be a vibration problems. After adding the HRS the turntable sounded rich and more controlled, with more continuousness and PRaT.

Considering the comparatively high price of the turntable, getting the HRS platform for it is a no brainer.

[Update 2014] Hopefully after all this you can look at your own components: solid-state or tube, thick heavy chassis or thin metal chassis, normal feet or feet with some kind of contrived technology [in our experience, component manufacturers who try and make vibration controlling feet fail miserably – but this is perhaps more a discussion on the Nimbus Coupler experience reports].

You can now predict with some degree of confidence the impact the HRS M3X will have on the sound of your component.

This is unique, in our experience, for equipment racks and platforms that claim to help with vibrations. Predictability. And no harmful side-effects.

Unless you really prefer your sound to be dense and syrupy, which, you know, some audiophiles do, these platforms and their couplers are a must have.



HRS SXR double-wide equipment rack: changing the height (or adding a shelf)

The happy owner of a new HRS SXR equipment rack wanted to change the height of the first shelf of the rack, from 10 inches to 12 inches, so that he could put his Lamm ML2.1 amps on the bottom shelf.

So we ordered up some new posts and went over to swap out the 10″‘ers for the 12″‘ers. I brought my camera.

A lot of photos but this whole procedure only took about a half hour, though I did forget to time it… so I could be off by a bit [i.e. don’t feel bad if it takes you longer, and if you do it faster? The heck with you :-)].

These racks are like audiophile erector sets: you can, by screwing and unscrewing posts, make them taller, wider (single-wide, double-wide, triple-wide and on and on), add more shelves [we’ve only seen them go as high as 4 shelves, but…they go down to 1-shelf which is amp-stand height. In fact single-wide 1-shelf tall SXR racks are exactly that: amp stands. Everything is interchangeable, and everything is so tightly spec’d, it just all works, no matter what your assortment of pieces parts is].

We turned the rack upside down and removed the screw on spikes.

Next we remove the nuts that hold on the bottom shelf. Here we are using the wrench that comes with the SXR to loosen a nut.

Once they are loosened, once anything is loosened, the precision construction allows us to just use our fingers and spin the nuts up off of the post [this is actually quite fun, just make sure you slow down when the nut nears the top of the post so it doesn’t go flying :-)].

Next remove the special polymer washers. The polymer used by these washers appear to be similar to the polymers used in the feet of the HRS platforms and in the Nimbus Couplers [soft hockey-puck-like things that go under a component chassis to control nastiness-causing brightness-causing blumpy-bass-causing vibrations – it consistently works really really well unlike everything else we and our friends and customers have tried]

Lifting the bottom shelf off the upside-down SXR rack

No, it is not all that heavy, per se, but the tolerances are tight enough that you have to lift it STRAIGHT up.

Put the bottom shelf to one side…

Next is to remove the posts that connect the bottom shelves to the, in this case, top shelf of this two-self rack.

This orange doohickey wrench thing is a really cool thing:

1. It allows up to loosen the posts which are screwed on tighter than finger tight
2. It will not mar the posts in any way
3. It allows is to tighten the posts exactly the right amount, acting as a torque wrench [if you try and tighten the post too much, it will start to slip… i.e. the coefficient of friction of the rubbery material of the wrench is just perfect to allow us to tighten the posts p-e-r-f-e-c-t-l-y].

These are bigger than the wrench that was shipped with the early racks, and, along with the bright orange color you would think we would not possibly misplace it. Yeah, you would think that [we did find it but it took a minute of looking – and I do NOT remember it being underneath my chair that I spent most of this process lounging around in ;-)]

I went around and loosened all the posts. Here Neli was being fancy and unscrewing 2 at once.

All the posts have been removed.

These bolts sticking out of the shelf are the same as the bolts on the end of the posts. Everything works with everything else because of these kinds of consistencies and extreme attention to detail.

Screw the new [taller in this case] posts on the upside-down top shelf.

Next put a tiny amount of oil on the threads of the new posts so that everything goes together silky smooth [seems to work :-)]

All the posts have been screwed on.

The bottom shelf has been alley-ooped back on the rack…

After putting the polymer washers back on, we put the nuts back on with Neli then tightening the nuts with the special wrench [again, a lot of manly spinning of the nuts onto the posts like they were tops on strings or something. Great manly-man fun :-)]

After we screwed the spikes on to the posts.

Ta da!

Because the floor was actually flat here, unlike our built-by-guys-on-drugs mid-70s home, the rack was perfectly level and there was no need to adjust the spiked feet to level the rack.

Took about a half hour I think, with most of the time spent by Phil and I unwrapping the new posts and re-wrapping the old posts in packing material sufficient [forgot to take photos! :-(] to guard against…well….

You know, after WWIII and we are all dust and after the radioactive wastes cool down, our 6-eyed descendents will have some kick-ass equipment racks to play around with.