Esoteric K-01

Has anybody had an opportunity to listen to the recently announced Esoteric K-01? I was also wondering about the price. Thanks
Heard it yesterday at the local audio show. Looks impressive. Couldn't gauge the sound quality as the entire setting was unfamiliar. The Esoteric rep thought that the P03D03G0Rb would likely be better (my old setup) but we didn't chat at length as I was there to buy Esoteric remasters and not audition gear plus he was super busy with a room full of devotees and aspirants.
Haven't heard it yet. The retail is $22.500. I am still a fan of the X-03SE.
Soundsreally is an Estoeric dealer and proper ethics dictate a disclosure when endorsing a line with a financial interest.

Dealer disclosure.

Not sure I can live up to your high? standards..
The Esoteric site has a fairly detailed descriptive PDF for the K-01. See:

It looks like K-01 uses 32-bit AKM DACs--8 per side. K-01 uses neither Burr Brown nor Analog Devices, making it potentially sounding different from X-01 D2 and P-03/D03. . This early in the game I would not venture to guess whether the K-01 exceeds the performance of the P-03/D-03 combo, or even of the X-01 D2. It is unlikely that any of the K-01 in the US right now are fully broken in. It may be a spell before we can get some detailed findings on this device.

FWIW - I have the 2nd generation 32-bit AKM DACs in my APL - NWO-ME Super-DAC prototype that I use along with my upgraded Esoteric UX-1, which I believe has the Burr-Browns in it. While I realize there are way more DACs in the APL prototype, so that any comparison is 4 apples to 20, I can't help but be impressed by the AKM DACs. Pretty much more of everything and the ability to get much further into the music - like a veil or 2 are lifted.
It will be very interesting to see how the K-01 sounds, especially after break-in. The only concern I would have is accuracy vs. musicality - not sure how Esoteric will handle that. The APL uses a double tube output stage, but I didn't see any tubes in the Esoteric.
>>11-27-10: Sounds_real_audio
Not sure I can live up to your high standards<<

Well I'm sure.

You can't.
APL NWO Master uses AKM 4399 DACs. K-01 also employs the AK4399. There are no tubes in K-01.... The Esoteric PDF file states: "A discrete buffer output circuit with a high voltage power supply of
+/- 22 V has been deployed for the analog audio output, following
the technology used in the D-01. [...] These powerful discrete buffer output
circuits are laid out symmetrically for each of the hot/cold signal
lines to construct a rich and fully balanced configuration for XLR
audio outputs. Additionally, a parallel buffer output configuration is
implemented to switch the buffer amplifier to a parallel
configuration, when RCA audio outputs are used."

As for K-01 being more/less precise/musical than APL NWO, I doubt that anyone has any hard evidence one way or another this early in the game.
Hello Guido,

The NWO-M has the AK4399 DACs working in an unusual configuration resulting in different level of performance.

The balanced transformer-coupled tube output stage has the following features:

1. Fully differential configuration
2. One triode per phase (hot/cold) on the signal path
3. No negative feedback
4. No solid state components on the signal path
5. Custom made Oxygen Free Copper output transformers by Lundahl, Sweden
6. Vintage E182CC tubes made in Holland
7. Because of the output transformer coupling, the user can enjoy exactly the same audio quality from XLR or RCA output depending on the preferred output configuration without any additional components on the signal path.
8. Filter-less design for linear phase in the hearing range.

Hope all is well!

Alex Peychev
Thank you Alex, info much appreciated. Undoubtedly, A comparative listening analysis of the two devices would make for a fascinating project.

You are welcome, Guido!

Absolutely; I am looking forward to that!

Best wishes,

Alex Peychev
We took delivery of the new K-03 and K-01 a little over 3 weeks ago. I believe we were one of the first if not the very first in the US to get them in.

As with the K-03, the K-01 has many digital filter and upconversion options which can be selected including defeating the digital filter and upconversion altogether. The player may also be used with it's built in volume control to drive the amplifiers directly. Each mode does require proper burn in before evaluation.

To date I have about 450 hours on the K-01 running nearly 24 hrs/day and it is breaking in nicely. While I will reserve comments and comparisons until I reach a point when I feel they are no longer improving, I will go on the record and state that this player is simply spectacular and has a sound quality that I have not experienced before from solid state digital.

Additionally, I have just begun listening with the G-0rb rubidium clock strapped on. Wow!! :)

Disclaimer: Esoteric dealer
Tony, you are causing me pangs of audiophilic anxiety mixed with generous amounts of neo-Freudian 'Esoteric envy'!

Can you already characterize any difference between K-01 against X-01 Limited and X-01 D2 (this last one on upsampling to DSD)?

And what about against P-03/D03 with same external clock?


Disclaimer: unabashed Esoteric fanboy.
I am privilaged to own APL HiFi NWO-S1 Player which, superficially, resemble K-03 i.e. it also has 2nd generation 32-bit AKM DACs--4 per side (K-01 has 8 per side). The Transport is based on Esoteric SA-50. Output stage is based on transformers and should be coupled to couple of transistors (to imporve bass) Alex use in NWO-SS series.

Extraordinary musical and involving. It took me much more then 1000 hours to break it in.

Alex The Magician - thank you very, very much!!!!!
To Tony007

Thanks for your comments. Any remarks on the K-03?

I recently purchased the Esoteric K-01 to replace the X-01D2. The K-01 is far superior to the X-01D2. The improvement was easy to detect, no A-B evaluation was necessary. The K-01 sounded extraordinary right out of the box, still cold. It is the best Cd/SACD player I have ever heard. I am trying out the G-orb, which I intend to buy, but its effect is subtle. The K-01 sounds great with or without the G-orb.

What? AK4399 DACs sound better than AD1955 and PCM1704? No, that cannot be! :-)

Of course I am kidding! Congratulations! I am sure the K-01 is another fine digital example by Esoteric!

Alex Peychev
Hi Alex,

I was unfamiliar with APL until today. I did a little research after reading your response to my note. Your NWO 4.0 is very impressive. It appears that Esoteric may have learned a thing or two from your work. I have some questions:

1)Why did you not preserve the ability to use a high end external master clock with the NWO (like the Esoteric G-ORb)? Do you feel a G-ORb could improve the performance of the NWO 4.0 if the NWO allowed for use of an external clock?

2) What is the retail price of a new NWO 4.0? How long a wait for delivery? Where can it be purchased?

3)Where can I listen to an NWO?

4)How do you brake-in the NWO for SACD (the Isotek disc is a CD). How much time do you feel the break in process requires?

Thank you.
Hi Alex,
My questions in my previous note are directed to the NWO Master version.
One more question:
What power cable(s) and interconnects do you recommend?
Hello Matjet,

I was unfamiliar with APL until today. I did a little research after reading your response to my note. Your NWO 4.0 is very impressive. It appears that Esoteric may have learned a thing or two from your work. I have some questions:

Thank you for the nice words! Ever since the NWO-1 was introduced 6 years ago, Esoteric Japan is aware of my developments. In fact, their team auditioned the NWO-1 and NWO-3.0-GO at CES. They have offered great support over the years for which I am very thankful and grateful, and I am very happy that their lead-design engineering team considered evaluating the AKM DACs and now implementing them in their products!

1)Why did you not preserve the ability to use a high end external master clock with the NWO (like the Esoteric G-ORb)? Do you feel a G-ORb could improve the performance of the NWO 4.0 if the NWO allowed for use of an external clock?

What I use from Esoteric players is the enclosure, the top-line VRDS-NEO transport (the same as in their P-01) and associated DSP that is also partially re-designed. Everything else is removed. This said, the entire clocking architecture is replaced with my proprietary modules. While I am sure Esoteric had their reasons for such design, I believe that my approach brings better results and does not benefit from external clocking at all. So now the clock input is transformed to coaxial S/PDIF digital input accepting up to 192/24.

2) What is the retail price of a new NWO 4.0? How long a wait for delivery? Where can it be purchased?

The older UX-1 and X-01 players (Including their Limited Editions) featuring the top-line VRDS-NEO transport are no longer in production, sorry to say. Depending on whether you'd like Universal playback (UX-1) or CD/SCAD only (X-01) a "donor" is required for the NWO-M re-design. The donor working condition is not of concern.

This is an all-hand-made boutique (including circuit boards population with microscopic surface-mount components, and point-to-point wiring) that is built to order by me personally and is sold factory direct. Current re-design cost to NWO-M is $25,000 with 3 years warranty included and it takes 4 weeks from "donor" and deposit receipt.

3)Where can I listen to an NWO?

I have several audiophiles interested in the NWO-M, so I am flying my own unit here from Europe. It is possible to arrange audition in the beginning of 2011. Please email if interested.

4)How do you brake-in the NWO for SACD (the Isotek disc is a CD). How much time do you feel the break in process requires?

I use dynamic large orchestra classical music for SACD burn-in. I was told once that there is SACD disc available with Pink Noise track on it, but I was never able to find it. As reported by my customers, the machine takes up to 500 hours to break-in, but that is the case with most audio electronics.

What power cable(s) and interconnects do you recommend?

I use my own cables so I am unaware what else works best, sorry to say. I'd recommend low capacitance solid-core OFC cables with minimal or no shielding using conductors with reduced surface area dielectric contact. Maybe it is good idea asking other NWO owners here on Audiogon or on my forum.

Best wishes for the Holiday Season!

Alex Peychev
I have the NWO 4.0 M for a few months now and I can tell you that this is by far the State of the Art CD/SACD unit currently available .

The unit bests my Spectral SDR 4000 Pro and the EMM stack and the Playback design MSP 5 that I also use in other systems.

The NWO 4 M competes neck to neck with my best Vinyl system ( Saskia turntable + Talea arm + Dynavector vxs1T). It is that good.

Be careful as once you have heard it, you will want it.
Hi Alex,
Thank you for your informative response. I have a few follow up questions.

What is the accuracy of the clocking mechanism used in the NWO M?

Could you explain in layman terms why a more accurate clock (G-ORB) would not improve the sound of the NWO M (if it were designed to accept an external clock)? Clock use with single box CD/SACD players is a controversial subject. Your answer to this question would help my understanding of this important topic .

Finally, what is your opinion on use of an external clock with CD players like the Esoteric K-01? (in view of your professional relationship with Esoteric are you able to answer this question objectively?). There are widely varying opinions throughout Audogon on this subject. I think you are well respected and have a large following on this site. I am sure a lot of people would lke to hear your frank, candid opinion on external clock use (especially highly accurate atomic Rb clocks like the G-ORb) with single and seperate box cd players.

Thank you.
Hi Alex,
I have a few follow up questions:

What is the accuracy (in ppm) of the clock(s) used in the NWO M?

Can you explain in layman terms why a using a highly accurate external clock like a G-ORb would not improve the sound of the NWO M?

Use of an external clock in single box CD/SACD players is a highly controversial subject. You are well known and well respected on Audogon. I am sure a lot of people would like to know your thoughts on use of an external clock. What is your opinion of using an external clock with single box players like the Esoteric K-01? Does it improve single (and multiple) box players? Why or why not?

Thank you.
I have asked this same question a while back, owning an Esoteric Rubidium clock and also Apl-modded gear. Once I understood the different functions of a "clock", I see why the external clock, while nice to have, is nowhere near as critical as the internal clock.

I'm not an engineer, but Alex and others have explained to me that the external clock controls the Speed or precision of the clock frequency. The precision of the clock frequency has nothing to do with the jitter introduced to the DACs but with speed ONLY. In other words, if your external clock is at a lower frequency than that specified, the music will play at lower speed and vice versa. So the stability of the external clock has nothing to do with jitter. Alex said his clocking approach reduces jitter to a level that is unobtainable even with an atomic clock, unless it clocks the DAC chips directly which is impossible. Having the internal clock in close proximity to the DACs (a few inches) results in greatly reduced jitter, which is audible as a purer signal output. Consequently, as I discovered, trying to apply external clock measurements to an internal clock totally misses the point, because they are controlling different things. That is also why most good CD mods will always contain an upgraded internal clock.

Hopefully, I didn't just confuse you; an engineer or Alex could probably explain this more clearly, or not :-). The point is, with the NWO-M, my G-Os Rubidium clock becomes totally extraneous for this system.
Based on your explanation, use of an external clock does not reduce jitter in a single box player. It should not improve the sound. It appears, an external clock could increase the noise floor and have an adverse effect on the sound.

Your comment, based on Alex's explanation, indicates that we are being misled by companies like Esoteric and DCS, and reviewers like Robert Harley who claim highly accurate external clocks reduce jitter and improve sound.

I would like to hear from Alex (and anyone else who cares to comment) on these questions/issues).

What are you doing with your G-orb?
While it does not reduce jitter, a good external clock can have some benefit, depending upon how resolving your system is and what the internal clock is doing. I have heard my system sound better with the external clock in it using my UX-1, but that's before the player has the benefit of Alex's clocking. I don't think I'll ever know whether an external clock would improve Alex's internal clocking because I doubt that he'll ever build a piece that would take an external clock.

I'm pretty much out of my league technically to explain this any further - I don't know WHY the external clock made things sound better, it just did. It was most noticed when I turned the external clock off - some of the airiness seemed to be missing. I'm sure Mr. Harley can explain this much better than I.

I tried posting a response but it looks like it was not up to moderator's liking, and probably for a good reason.

Anyway, here is a summary of what I think:

1. Esoteric digital is synchronous so it benefits from external clock for the sake of synchronization between multiple clocks used, even in the single-box players. If you are trying to justify external clock for your K-01, I am sure you will be happy, so go for it.

2. APL Hi-Fi digital is asynchronous so there is no benefit from using external clock, even if it is Atomic.

3. To my knowledge, clock stability has nothing to do with clock jitter. For example a clock rated at 25ppm will result in 0.0025% speed stability. Clock rated at 1ppm will result in 0.0001% speed stability. In both cases, this is something you cannot hear and in both cases the clock jitter performance (short term stability) remains the same.

Best wishes,
Alex Peychev
Hi Alex,

I appreciate your response. However, I am still confused.

If a more accurate external word clock does not reduce jitter, how does it improve sound in a single box CD/SACD player that has only one master internal word clock? Synchronization by an external clock would be unnecessary since there is only one clock. The unit's transport is 'slaved' to the internal clock which connects with the DAC. The transport and the DAC are already synchronized by the single internal word clock.

According to what I have read (at least the way I understand it), it is inaccurate timing and/or timing errors that lead to clock jitter. A more accurate and more stable word clock, provides more accurate timing and fewer timing errors. The result is significantly less jitter resulting in improved sonics.
Is this not an accurate statemnt? Please explain.

Could you explain the difference between asynchronous and synchronous digital in layman terms and tell why you feel asynchronous digital is better than synchronous?

Thanks again
Hello Matjet,

Different engineers like to take different design approaches, the ones they believe are best for their equipment. This said, I cannot further elaborate on why external Esoteric clocks improve the sound of their digital audio equipment without getting into technical details which may be a conflict of interests and against the non-disclosure agreement we have signed. Maybe it is a good idea to contact Esoteric and ask them to provide an explanation that will help you better understand the benefits of their external clocking when used with their digital audio players and systems.

I have chosen asynchronous because it brings better results with my design approach.

If you are indeed interested auditioning the NWO-M and evaluating its performance, we can arrange it. Otherwise, there is no point trying to prove what we think is better or not from a technical point of view. After all, the audio quality achieved is the most important aspect, and I am sure that it will take you about 30 seconds to determine the NWO-M performance level. Of course, it is not at all fair comparing production equipment with an all-hand-made boutique. This is the reason why Esoteric and APL Hi-Fi do not really look at each other as competitors. Hope you’d understand!

Best wishes,
Alex Peychev
And the sell-a-thon continues from whichever continent apl is currently based.

Subject to change of course.

Maybe tomorrow.

Or Tuesday.

There are many audio manufacturers currently based on two or more continents.

The NWO-M was developed in Europe, as well as the new DAC-S, and we have more products coming up, so I think it was a great success. Aren’t you happy for me? :-)

Best wishes,
Alex Peychev
I'm tickled pink you can stay in one place for 30 days.

I believe that's a record for you.

I also believe the forums are no place for selling.

Glad I could help.
Glad I could help.

Thanks much Bill, you're the best!


Alex Peychev
Alex is being upfront.So frankly I don't see what the problem is.
You think using the threads to sell is ok?

Well I respect your opinion but not those who do it.
If the dealer is upfront I think anyone with half a brain knows to take comments with a grain of salt.Alex is also providing some useful and interesting input( and NO, I am not a customer of his).I do have a problem with people/companies posting under several aliases though.Members like Audio4ever come to mind and there are many more. I really appreciate it when a dealer is upfront.They are the kind everyone likes to do business with.I also appreciate your honest input.
Audiofeil, I have reviewed many of Alex's contributions in Audogon (and elswhere). I have never met him and do not own any of his products. My inmpression is that he is a gifted and probably brilliant, driven, obessive compulsive perfectionist audio equipment designer. He has made many contributions in various threads which clarify some very controversial technical audio topics (clocks, for example) which no one else has answered competently or honestly (including several reviewers). I am not at all offended by information he provided regarding purchase information of his cd player; I asked for it.

Based on my review of Alex's comments here (and more importantly elsewhere) and my own listening experience, I believe that extremely accurate external clocks (even atomic clocks) do not benefit single box CD/SACD players, only seperate box equipment (DAC/transport separates) which require synchronization and are unable to synchronize themselves. Single box players are already synchronized. Possibly, if the single box player has a very poor internal clock, it might benefit from an accurate external clock. But why waste money on a lousy player with a lousy clock then try to improve it with an expensive external clock? That does not make sense.

If anyone would care to comment on my observations and conclusions, I would love to hear from you (that includes you Alex).

I have learned a lot from Alex's posts. He has contributed greatly to Audogon.

Audiofeil, I have two questions for you: Who made you sheriff? Why don't you stop harassing people and get a life? Your remarks are not constructive.
You think using the threads to sell is ok?

Bill, last time I checked, you did not miss answering questions about your product line on the forums, correct?

If my responses were not addressed to specific questions, Audiogon moderators will not post it to begin with, and you know that very well. So I don't understand your point, really!

Alex Peychev
You'll never see or read me promoting any products in my lines Alex.

Unlike you.
If you were a design engineer/manufacturer, Bill, you would probably not be so smug nor disrespectful. The fact that Alex even participates in some of your baiting is remarkable to me - I certainly wouldn't.

It is always beneficial when a manufacturer is able to answer questions directly, as a number do from time to time on these forums. I find their input valuable as do many others. Your blatantly obvious "ax-to-grind" attitude towards Alex helps no one.
Audiofeil - I think that it would be beneficial to audio community in general if you write about your audio discoveries / experiences or whatever instead of wasting your time bashing other manufacturers / products / dealers.

It is not fun to read anymore (if ever was) and is just annoying.
Thank you for the nice words Matjet, I appreciate it!

If anyone would care to comment on my observations and conclusions, I would love to hear from you (that includes you Alex).

I think you are on the right track about external clocking.

The single box player transport clock is indeed slaved to the DAC clock. If you use external clock, you are slaving the DAC clock to it, which then slaves the transport.

With separates, DAC clock and Transport clocks are directly slaved by the external clock.

While there might be some benefit using external clock with a single box player of given synchronous design, the improvement is a lot more pronounced with separates, IMHO!

Best wishes,
Alex Peychev
To chime in on the topic input quality here, I'm also inclined to state that, over the years, Audiofeil´s sour sarcasm and aggressiveness are hardly enjoyable. Ceaseless negative posting in the h-cat preamp thread comes to mind. Maybe Audiofeil has lost sight of the fact that he is a dealer, while AP invents and manufactures his machines. Or maybe, he rather has not? Clearly, the dealerless business model of the genius-freaks behind APL, Wyred, H-Cat, Empirical Audio, Altmann and many others is quite contrary to what might be to the liking of a noblemainstream-products retailer.

Yes, some inventor-entrepreneur´s model politics and marketing slogans (New World Order and the like) may be questionable or well over the top. However I find the existence of those tiny avantgarde/non mainstream companies refreshing and vital. As well as their founder´s contributions in the forums, as long as sales intentions are not blindingly obvious.
Matjet, my own limited experience on Esoteric X-01 Limited and Esoteric P-03/D-03 combo driven by G-0S clock are consistent with the opinion that external clocks appear to have little or no impact on single box units, but can have a major impact on the sound of twin boxes.

Every time I heard G-0S driving X-01, I found the effect to be imperceptible. Conversely, G-0S always had a clarifying effect on P-03/D-03 that has ranged from major to profound, depending on the IC being used.

I am inclined to suspect that G-0S may end up being also a negligible factor on the APL NWO variants and on the new Esoteric K-01.... but only direct experience can yield certainty.

As Bill is an Esoteric dealer, I invite him to share his knowledge on the effect of external clocks on various Esoteric single and multi-box players.


Hi Guidocorona,

I tried the Esoteric G-ORb with the K-01.

Use of an external clock with CD/SACD players, especially single box players is still quite controversial. There is a lot of misinformation floating around. Part of the problem, in my opinion, is the detailed reviews by Robert Harley in Absolute Sound on the G-ORb and more recently with dCS Puccini. One would believe, after reading these reviews, that an external clock (especially a super accurate one like the G-ORb), significantly improves both one and two box players. That simply is not the case. I also suspect that Mr. Harley's concise description of how a more accurate external clock reduces and/or eliminates jitter is very wrong. If I am correct, he has done a great diservice to the high end audio consumer community, creating a great deal of confusion.

I spent a great deal of time listening to all types of music at different volume and from different listening posisitions (mostly prime listening position). I tried A-B comparison as well as lengthy listening sessions. I focused on various aspects of the music reproduction (timbre, decay, 3 dimensional sound staging, instrument separation ('air'), bass, treble, cymbals, guitar and piano notes and decay, transients, voice, classical, blue grass, jazz,rock, you name it, I tried it. I really wanted the G-orb to improve the sound in some manner, but in all honesty it didn't do a thing to improve the sound of the K-01. The K-01 sounds EXACTLY the same with and without the G-ORb; that is SUPERB! So, I will not be buying the G-ORb to go with my Esoteric K01.

I encourage coomments from all on this interesting, controversial topic. That includes you too Bill. We have heard from Alex on this subject. What are your thoughts?

To All: Bill is probably very knowledgeable about audio equipment. I am sure we could learn a lot from him. It is unfortunate that he chooses to expend his energy and time 'policing' Audogon rather than comtributing by sharing his knowledge and ideas.
I'm on the same boat. I did not hear the improvement from adding a clock to my Puccini integrated player, and yet I can clearly hear its effect on dCS separates.
Hi Elberot2
That is very interesting! Thank you for your input. I would like to hear from others with external master clock experience.
Keeping to the topic: I utilized a G-0s in Rb-oscillator mode at 176.5 clocking rate with my UX-1 Limited; I did find a perceivable improvement in the sound. It was more subtle in some ways but was there and was noticeable when the clock was removed. I also agree with a prior poster that for synchronous digital playback a hyper-accurate clock (ppb rating, not ppm) does provide benefit. With single box players as I mentioned above, the improvements are more subtle, however, with multi-box stacks (like the P-03U/D-03 combo), the improvements are very noticeable, obvious and missed when the clock is removed.
I utilized a G-0s in Rb-oscillator mode at 176.5 clocking rate with my UX-1 Limited; I did find a perceivable improvement in the sound.

This is very interesting because the UX-1 Limited converts DSD to 88.2

Did you hear this improvement with CD or SACD, or maybe 176.4 DVD-A?

With single box players as I mentioned above, the improvements are more subtle, however, with multi-box stacks (like the P-03U/D-03 combo), the improvements are very noticeable, obvious and missed when the clock is removed.


Alex Peychev