REPORT: Inakustik AC-3500P POWER STATION and LS-4004 AIR speaker cables

The Inakustik AC-3500P power station and LS-4004 Air speaker cables could be the Valedictorians of Power conditioners and Loudspeaker Cables!  Howard Milstein disseminates them and takes a serious look as to why! 

Being a reviewer and commentator within this illustrious, though maybe sometimes, laborious hobby, I’m fortunate enough to be able to listen to some of the most demanding and exquisite audio components produced by some of the finest designers in the “high-end” community. Unfortunately, sometimes this can take its toll on the amount of time I spend listening to music.!

On the other hand, when new products are presented for me to evaluate and listen to, one usually finds that the time and effort spent was well worth the awards and satisfaction we may have gained in the process.

A few months ago, The Inakustik AC-3500P power station and LS-4004 Air Reference speaker cables were given a short preview in the Sound Advocate after having been immensely impressed from their initial auditioning  within only a few weeks of introducing them into my system for testing.

As promised then, here is a full review of these 2 consummate audiophile products. I will outline some of their technical aspects while interpolating the various audible listening impressions I have perceived in the few months I’ve had the AC-3500P power station and LS-4004 Air loudspeaker cables installed in my system. If you would like to read more specifics about Inakustik’s background and products, please see the above link of my preview or at the Inakustik website.


Inakustik AC-3500P power station

The Inakustik AC-3500P is an Active “high definition” Power/Filter station that uses one of the most highly efficient centralized parallel filters currently available. Most traditional filters can many times, squash dynamics of the reproduced sound which Inakustik sees as being particularly true for serial circuits: the inductors that are inserted into the feed line definitely increase the transition resistance and hamper dynamic pulse currents.

The Reference AC-3500P power station has used a different approach: it implements a highly efficient, parallel filter that is executed most perfectly and exquisitely, thereby noticeably increasing the definition of a high end audio systems complete overall quality of sound reproduction. These include, but are not limited to dynamics, stage depth and width, ambience, and quite shocking to me, a level of increased “audible truthfulness” to a system that is hard to define completely in mere words yet is inexorably perceptible when listening to the finest source material through the most demanding audiophile components.

Inakustik AC-3500P power station and LS-4004 speaker cables

The filter used in the AC-3500P deters all interference from both the power system and the connected devices themselves without restricting the supply. Adding to this is the dampened sub-chassis that reduces the AC-3500P mechanical vibrations of the filter components caused by the 50-Hz grid frequency. Inakustik uses a star-shaped distribution topology which eminently ensures a uniform supply of all the connected components you may be using. In this way, it can affect the full audio resolution of just about any great high definition system. The Reference Power Station AC-3500 has, for me, become an actual ‘component’ in and of itself within the constraints of the particular equipment within my reference system or any other audio component that has subsequently been inserted for evaluation.

For this assessment, a good variety of reference components and loudspeakers were employed in order to instinctively appraise the sound attributed to the AC-3500P power station. To begin, this ‘Power Station’ appears to be able to improve on just about everything; right out of the box!  What is somewhat hard to totally understand is how and why its specific and unique design qualities are actually doing what they do and doing them so well!

We know that the average, quality power conditioner, being ones from Audioquest or Nordost, to name just a few, will generally give you a first rate, deeply satisfying and admirably silent musical backdrop when enjoying and relaxing with your system and favorite music. The AC-3500P however, goes one step further: It brings forth in the most neutral, self-effacing manner, much more of well-engineered recordings low level, precise details, and definitive transparency; both of these attributes being the true ‘hallmarks’ of the AC-3500P power station. Now you might be saying to yourself, “sure, this conditioner could very well be adding its own coloration or personal ‘inherent’ aberration to the system chain within its performance parameters, making it sound more appealing, but possibly less naturally authentic than by going straight into your mains outlet”. As some audiophiles already believe that a power conditioner may be an unnecessary addition and added expense to a well-tuned system, and in some cases restrict a component’s natural performance qualities (e.g., power amplifiers). This is where the Inakustiks’s AC-3500P becomes so remarkable and quite unique

When the AC-3500P was initially installed into my system, I immediately noticed the reproduction of some of the foremost program material I could throw at it becoming increasingly more ‘live’. Let’s try to explain this. The music was brought forth, while never jumping at you and in no way sounding brash, forward, strident or indeed, unnatural at any time, a feeling of unmasking a tiny thin layer of ‘haze’ from recorded musical Instruments and voices inside the sound scape while simultaneously becoming a touch more spacious within the core of the audible perspectives being exposed. The component was able to cultivate the sonics of a recordings finely subtle, musical nuances and instrumental tonal characteristics which was ultimately perceived as being more authentically musical.

The AC-3500P, in a narrow yet formative way, digs deep into a recording with a mere touch of “spatial” and undeniably accurate recording venue ambience and transparency that coerces you to feel like you are just sitting in the best seat at a concert hall hearing a live performance before you.  

What’s more, the unit appears to take on an even more daring task. The above-mentioned characteristics give the listener the impression of ‘detaching’ more of the inherent audio reproduction characteristics from all the loudspeaker cabinet boundaries that were employed — thereby allowing the music to expand slightly in overall sound stage depth and particularly width. As you use the AC-3500P longer, this intrinsic and deeply audible characteristic remains in your psyche while quite importantly—it keeps every bit of the stereo image localization that the source material may present right there in its original form.

Thankfully, if your current system has a well-tuned mid to low bass response, you will also notice slight incremental increases in bass tightness and impact when the recording displays as such. As for the mid to upper frequency response, it was like an ‘ethereal’ light had been turned on in a lightly dimmed room that you can now see clearly from every corner. The music emanates so exquisitely and distinctly as before, with an ever so slight, but important (not psychological) realness to the tonality and complete sonic picture emerging before you. I hate to sound like a true “nutcase” but the AC-3500P does something to the sound of a great system, which while adding to its unforgiving “quietness”, takes great recordings and just lifts them so perfectly ‘up’ to another level of quality.

Quite normally, to improve the overall sound quality on a good reference system, a heavy investment in source, amplifier or loudspeakers may be mandatory. The AC-3500P power station will let you enjoy music in a way that bares quite a resemblance to having just bought an extraordinarily terrific new piece of electronic gear while acknowledging its amazing value at its standalone price of $3000.00 USD.


Inakustik AC-3500P power station Inside

The technical design of the AC-3500P is housed in a stout metal enclosure with a front panel of silver or black anodized brushed aluminum. (either one being a sight for sore eyes!) Six high-quality power sockets are available at the rear panel. The centrally placed high-current power inlet (IEC C20) allows for easy replacement of the supply cable – for example, if you may need a longer one. The unit has a built-in surge suppressor that protects all your components from voltage peaks, and you can conveniently switch all power sockets on and off using the power key on the front panel. An indirect LED light located at the front-panel bottom shows the current operational status: white is for the standby mode while blue indicates that the Power Station is on and the power sockets are active.

Having a 20 Ampere inlet, the Inakustik power station design was meant for handling high currents (amplifiers) while individual outlets are separated as well, coming with a flap cover to close if the outlet is not used.


The Inakustik’s AC-3500 P comes with a standard power cord included in its price. However, Inakustiks has another power cord option, namely the newly upgraded 2502 power cord that now has a 20-amp connector at the conditioners end with a Furutech F1 32 connector and F1 28 connector which goes into the wall’s mains outlet. This 1.5-meter power cord is now included with the purchase of the AC-3500P; exclusively in North America.

Although admittedly, it was a bit harder to notice any major sound quality differences when replacing the updated 2502 with Inakustik’s standard AC cord, I personally felt a bit more confident when using 2502 mains cord with the 3500P. Others may indeed find more plausible differences depending on the particular area they reside in as well as the overall quality of their incoming power.


Inakustik AC-3500P power station LS-4004 cables

I was fortunate enough to be able to audition the latest version of Inakustik’s AC-2404 air power cord. This power cord is quite thick, beautifully wound and immaculately terminated with Inakustik’s new Furutech NCF connectors, which are considered by many to be the best in the world. In the context of ‘high end’ audiophile power cords, the AC-2404 is by no means inexpensive. On the other hand, most readers will be familiar with many other top end power cords currently available that in some cases, may indeed cost quite a bit more than the AC-2404. Inakustik’s use of their AIR Helix construction is categorically unique. (as you will see further down in my evaluation of the LS-4004 loudspeaker cables.)

In order to come as close as possible to perfect air isolation, Inakustik has developed these types of special clips. Inside the cable, a large number of these clips form the supporting framework, which keeps the signal conductors helically free in the air and guides them through the cable at a defined distance.

When combining Inakustik’s Air HelixTechnology or the “omission” of isolation material, which normally would “soak up” energy like a mop, the Reference AC-2404 will impede these unwanted effects making it, in effect, a straight and direct electrical pipeline.

For the context of this review, I was allotted one of the Reference AC-2404 cords and I aptly switched them between my digital sources and preamp, power amp and/or DAC. However, generally speaking, if you only have access to one AC-2404, it best is used on your source components. The North American version of the Inakustik AC-2404 Air power cord in a 1.5-meter length only retails for $2,500 USD and it comes with the top Furutech NCF connectors. The same cable in a 20-amp version retails for $3,000 USD.

Nevertheless, offsetting their respective prices, and having had the opportunity to evaluate excellent power cords from Nordost, Wireworld and Audio Arts, the AC-2404 turned out to be an impeccably efficient and noteworthy addition to their full line. Not only did this power cord bring forth an even more intense audible quietness to the music, but they were able to plunder away that last morsel of extra “lucidity” emerging from the loudspeakers and the music itself. When the AC-2404 was connected and combined to the AC-3500P power station, I had the overall sense that most of my finest recorded music sources were being presented to my ears with the utmost finesse, definition and the absolute last increment in tonal purity—or to put it bluntly, possibly the finest sound combination I had yet heard from my system!  

Specs: Outputs: 6
Supply voltage: 100-250V AC / 50-60Hz
Operating current (max.): 30 A
Input power (max.): 3,680 W (120 VAC, 30 A)
Dimensions: 450 mm × 370 mm × 160 mm (W × D × H)
Weight: 28.25 lbs
Power inlet: IEC C20 socket


Inakustik LS-4004 speaker cables

I have been using this ‘top of the line’ loudspeaker cable by Inakustik now for approximately 3 months. At first, I was a bit apprehensive about evaluating a cable such as these– mainly because at their not so inconsiderable price point, “What would I do if I really enjoyed these cables?”

In my opinion, only the very best systems will require costly cables priced at more than $100 per stereo meter. However, in the context of a well-balanced $30,000 system and upwards, an extra $4,000 spent on loudspeaker cables of sensible length is clearly money well spent in terms of total system sound quality.

Originally, Inakustik sent me the double ended cable which was later replaced about a month later by the single ended version. For those audiophiles who bi-wire their loudspeakers, the double ended should prove invaluable.

In fact, when my sample of the single end version arrived, there were initially some small differences in the sound quality between the two, which I will go into further on. The end result is that generally speaking, these huge, thick, exceptionally made cables may need some break in time, as can be expected from most of the finest high-end cables currently on the market.

As seen in the photo, the LS-4004 comes in a no nonsense, large, good looking and well packed box with all the relevant paraphernalia and instructions on their usage included.

Inakustik AC-3500P power station and LS-4004 speaker cables

Upon unpacking, one notices that the ends of the cables are further protected within small soft velour ‘bags’ and removing these exposes the ultra-high-quality bespoke connectors – my second sample was delivered with the above mentioned single wired spades at the amplifier end and banana plugs at the speaker side. The high conductivity tellurium copper spade connectors have a very astute angle adjustment which allows for a degree of adjustability when connecting to binding posts which are either close to the ground or within a tight space. What’s more, and of considerable value, the spade ends can be removed and changed over to accept any configuration of spade and banana connector, which I eventually did.

Inakutik’s research has ultimately confirmed that tellurium copper as the plug base material offers twice the conductivity as brass terminations. The connector surfaces are then rhodium-coated which insures optimum contact over long periods of time.


The LS-4004 continues on, as with their power cords with Inakutiks Air Helix technology. This cable uses approximately 16 Cross Link Super Speed waveguides made that are made with high purity copper wires, each with a split hair-thin lacquer coating for advanced insulation. The wires are then braided around a PE core network jacket. There is no solder being used here.  As such, the contact resistance is minimized and the conductor quality and conductivity are maintained. In this sense, we see a familiar tendency for Inakustik to have concentrated on the problems found in the formation of eddy currents. (see Wireworld Eclipse 8 review). The above technology ensures that the LS-4004 Air dielectric is the ultimate example of super low inductance, low capacitance speaker cable; thereby ultimately procuring all frequencies are transmitted freely and without any latency whatsoever.


Being the top-level speaker cable in the Inakustik portfolio, The LS-4004 proved to be an amazingly impressive speaker cable, as well as it should be at its retail price of approximately $6,000 per terminated 3-meter pair, but of course, pricing will vary depending on the length you require.

Cable choice, as Ive mentioned countless times before, in many of my recent cable reviews is complicated by some standard of system dependence, and they often have a degree of ‘character’ which may complement or fight against a given system. A strong, low resistance cable such as the LS-4004 can often be better with low impedance speakers. It will also be an effective partner for many high-power speakers with current-hungry bass sections. Strong, low resistance cable is often better with big low impedance speakers, and here, spades may be generally preferred as the best termination.

Not knowing what to expect from these extravagantly priced cables before set up, I was secretly (hoping) that the LS-4004 would turn out to be not all that it had been made out to be from its North American Importer, Robert Neill. To my surprise, it took only approximately 2 hours of listening to some streamed live performance recordings and an amazingly recorded, 16Bit-FLAC cd-r ripped recording of Colin Davis’ live performance of Smetana’s ‘Ma Vlast’ to uncover these cables virtues! Adding to this was some finely remastered recorded folk music programs available (Peter, Paul and Mary DSD 2.8 MHz/64fs) that made me reluctantly concede that the LS-4004 was probably the finest loudspeaker cable I had yet heard in my system, while teamed up with a few exceedingly excellent electronics and loudspeaker combinations they were tested with.

Within a short amount of time, full musical works and tracks of recorded music that I was immensely familiar with started to spring forth with small, but emotionally important distinctions that heretofore were somewhat taken for granted. These audible traits included, but were not limited to: violins, massed first and second orchestral strings, percussion, brass and last but by no means least, woodwind instruments.

The LS-4004 was able to increase the tonal clarity of these instruments within the complete soundstage presented. Harmonics in music are notes which are produced in a special way; being notes which are produced as part of the harmonic series”. While the LS-4004 was demonstrating these admirable traits in very tiny ways, the music as a whole was brought forth with an unmistakably powerful sense of poignant and passionate verve.

As additional source material was introduced, I was able to experience this more and more. (digitally, with the extraordinary sounding Audio NoteCD-3.1x/II Vacuum tube CD player/transport ). The cables exhibited close to perfect ambient decay, depth and lateral sound stage openness with explicit realism in regard to the sound as it floated back behind and to the corners of the front of the listening room. The stereo imaging was always locked solid and profoundly placed within the imaginary three-dimensional space created by the high-fidelity reproduction of sound in the loudspeakers used. In effect, if your loudspeakers are up to the task, the LS-4004 was basically taking the speakers out of the picture, completely and particularly when mated with the AC-3500P.

Most importantly, these cables were of such low coloration and neutrality, that the finest soloists, orchestral instruments, pianists and vocals, if recorded properly, could let your imagination truly envision the performers in front of you. When you can just about imagine a full orchestra playing as if you were in their concert hall and not your home, you know that something special is going on; and indeed, it was!  In essence, these cables gave the listener a much easier time for your audible senses to be able to imagine all the above.

The Inakustik LS-4004’s were able to convey a lavishly solid, deep bass/midbass response along with amazing focus and dynamics while at the same time exhibiting an understated perception of balance coordination and an expertly executed transition into the midrange and high end. Never sounding rough, acidic or course, they could prod deeply within a recording of mass violins, while at the same time enabling one to sometimes differentiate the actual individual string tones as they played in unison. This was startling observation and it is something that I personally find deeply emotional when listening to most of my classically recorded program material.

As for vocals, I put the Inakustik cables up against the excellent Wireworld Eclipse 8 for a session or two. These Wireworld cables give transparency to female vocals that are quite hard to resist, particularly being 1/3 the price of the Inakustik LS-4004 Air. On the other hand, intense critical listening of many recordings, including one of my reference vocal recordings, the remastered 192 kbs flac recording of Janet Baker singing Elgar’s Sea Pictures, reminded me that the LS-4004 retained a spec less decay time (smearing) within the listening acoustic while also being a trifle more exact reproducing her inexorably gorgeous mezzo-soprano silkiness and definition.

Needless to say, the Inakustik LS-4004 is an impeccably made and sounding loudspeaker cable that is able to reproduce the natural qualities of all voices and acoustical instruments with definitive transparency, a neutral, uncolored tonal balance and a degree of audible purity that warrants partnership with some of the most eclectic and esoteric audio systems currently available.


  • Air-helix structure
  • Air dielectric ensures extremely low capacitance
  • Cross Link Super Speed waveguide technology
  • Double Layer Multicore
  • Directly crimped connectors (1.5 T pressure)
  • Tellurium-copper connectors


We can obviously agree that a direct connection from an amplifier output terminal to the speaker input terminal, or basically no cable as such—is the theoretical ideal and nothing can be more accurate; scientifically and/or subjectively. This is particularly relevant when using many of the most pronounced audiophile cables currently being manufactured for the upscale audio enthusiasts and music lovers among you.

If you are one of the music devotees and audiophiles who might be lucky enough to be able to have an audio system consisting of some of the most exalted components you want– without to much consideration of cost, you must audition the Inakustik Reference LS-4004 air speaker cables, power cords, and the simply astounding AC-3500P power station.

Although admittedly, I have not assessed the top of the line cables by Siltech, Transparent Audio or Nordost, at the moment, the LS-4004 Air Speaker Cables, though costly, are less expensive than the above products, and most importantly, are of reference quality as well as demonstrating the current ‘state of the art’ in their overall build, musicality and performance attributes. These cables are just about flawless in the way they transform music from any set of reference electronics and loudspeakers they may be used with.

As for the Inakustik AC-3500P power station, it is safe to say that this is the finest power unit I have ever used. The AC-3500P is much more than a power conditioner by any means!  It is a totally complete, astoundingly quiet parallel filtering conditioning system, that somehow brings forth a caliber of subtle, natural and deeply hidden musical characteristics in a given recording that in most cases, had been previously unnoticed. As already mentioned, it is a breathtaking component within itself that once embedded into your system is hard to live without!

As such, I have since purchased the AC-3500P and LS-4004 cables as well as the Air 2404 reference power cord and will be using them within the context of future product reviews for The Sound Advocate. They have subsequently been named one of 2 “Best Products of 2019”.

PRICING: Inakustik AC-3500P Power Station ~ $3000.00 USD ~~~ 1 x Standard US power cable

NOW INCLUDEDNorth America ONLY: Inakustiks 2502 AC-3500 upgraded power cord

Inakustik AC-2404 upgraded Reference Power Cord 15 amperes, 1.5 meters – $2,500 USD ~ NCF 20 ampere power cord ~ 1.5 meters – $3,000 USD

Inakustik LS-4004 Air speaker cables ~$6,000 USD – 3-meter pair /terminated

Review System  Rega Planar 6 Turntable/RB300 arm / Ortofon Cadenza Bronze cartridgeAudio Note (UK) CD 3.1 x/II player/DAC  / Wyred4Sound 10th Anniversary DAC/  Peachtree Audio Nova 300 2019 (preamp/DAC) ●  PS Audio Stellar Gain Cell power amp/phono preamp• CIA Audio C100S Power Amp ● Loudspeakers •Audio Note (UK) An-E/D loudspeakers / Spendor BC1/ Aerial Acoustics 6T/ Quad ESL 63 USA. Cables: Wireworld Eclipse 8 interconnects/speaker cables & Electra 7 power cords/ -Audio Art IC3 e – 75ohm COAX & power 1 e” AC cord / Wireworld Gold Starlight 8 – 75-ohm coax / Nordost White Lightning Speaker Cables/Blue Heaven Power Cords

North American distributor; Worldwide Wholesales

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phone number; 519-619-9924


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