SW1X Audio Design DAC II Absolute Top Tier Ref NOS DAC


It has been over 4 years since I have ventured back into the DAC arena, a cautious adventure being that I was never satisfied with the sound quality of the Lampizator Level 4, Berkeley Alpha and an Eastern Electric DAC. All of them had their strong suits in one area or another but they were not at the level of my modified Modwright Sony 5400ES or Marantz SA8005 Tube CD Player.

I had been following the DAC threads for some time and was optimistic and hopeful that technology had improved or at least the deign implementation, so I private messaged a few knowledgeable members to get an idea on what they have heard and seen at shows and in their systems. After several suggestions and myself doing some reading and research on the different technologies, I decided that the Border Patrol with SPDIF would be my first entry back into the digital age.

The moment this DAC was installed into my system, I began to understand from my listening experiences that R2R was the DAC chip that provided an unmistakable level of musicality and toe-tapping emersion into the music. Now, I knew the direction that was set before me to find my reference DAC with R2R DAC Chips, Non-Over-sampling or filtering. I began to notice a trend in different approaches in the implementation/design of technologies and have heard through-out the Audiophile Community that Audio Note was the “Standard” in producing “Analogue Sounding” Digital to Analogue Conversion. The BP DAC solidified this in my mind, whose roots are also from Great Britain.

After discovering the similarities of these DACs, I decided to contact an Audiophile friend in Great Britain to determine if there were any DACS in the spot-light that was knocking on the doors or even beating the legendary Audio Note sound quality? He steered me to a small company that is taking Europe by storm and after a week of reading their philosophy and design implementation, I decided to contact the Founder, Managing Director & Chief Audio Engineer on which DAC would suit my system and yield the best sonics without spending an absorbent amount of money…

After making contact with Dr. Slawa, Roschkow, I took his recommendation on the SW1X Audio Design Dac II STD ($3,200) and I am in agreement with his Philosophy on design, implementation and many aspects I have never heard of but his knowledge is quite impressive to say the least and has been very responsive to all of my questions. Here are some aspects of my DAC listed from:


SW1X Audio Design™ DAC II Features:

-Specially selected and harmonically matched component & material quality based on performance level 2 standard:

- AN Kaisei, Philips BC, Siemens capacitors, Allen Bradley resistors, complementary silver and copper wiring technique everywhere

- NOS (Non-oversampling –zero digital domain filtering) design

- Based on 2 x PCM56 K – the most refined and highest resolving sounding 16 bit DAC chips ever produced (yes, even cleaner and more refined than most 24/32bit Delta Sigma chips) directly connected to CS8414 S/PDIF receiver

- Active I/V conversion via a special transistor (with less than 10 Ohm input impedance) with the shortest signal path directly connected to the tube grid

- Single ended, anode follower, zero feedback, 6N6P/ECC88 double triode valve output stage

- Output stage signal decoupling capacitor options a) Bosch PIO or b) Audio Note Copper Foil Mylar in Oil capacitor

- 6X5GT double diode valve rectified CLC (choke filtered) HV power supply

2 separate mains transformers for the DAC and the valve output stage circuits

Custom Germanium transistor based shunt voltage regulated power supplies around PCM56K circuit

Supports 24Bit/96kHz digital coaxial S/PDIF signal input

110/115/230/240V AC mains transformers


As a reference, I have been listening to my new CDs that I got as a gift for the past 4 months which includes The Touré’-Raichel Collective (The Tel Aviv Session), Audio Note Ambassador, Vincent Be’langer CD titled Pure Cello, Three Wishes For a Rose, Ma Xinhua (Cello), Feng, Dan (Piano) and The Spirit of Gambo, The Galaxy Recordings (Direct Cut Super Audio CD) which I am a big fan of string type instruments and in fact is what I primarily listen to and have a good grasp on any changes that could be discerned by implementing new equipment within my system.

My DAC II STD (13.5” W x 16” D x 5 ½” H) safely arrived from Great Britain, unit was packed very well and received in pristine condition. Digital inputs include AES/EBU and SPDIF and the Output RCA has 2 sets of RCAs which I imagine one set are Silver or Rhodium-Plated Copper and the other Copper, so you will have a choice in fine tuning the sound you prefer and not to mention the possibilities of tube rolling to ones’ desires… I also believe USB inputs are also available upon request.

I delayed my initial impressions after install since I was waiting to accomplish our daily nightly routines with the kids before settling down in front of my system, knowing that it is going to take hundreds of hours before the capacitors starts to form and settle in and another 50+ hours to hear the tubes at their best; 96 total hours on DAC II. I cued up the first track on The Tel Aviv Session, Acoustic Guitar followed by Pure Cello was blown AWAY! I was hearing things that were never hinted at on my previous playback and quite frankly, didn’t hear this wearing Audiophile head-phones. I was struck by the uncanny realism of musicians occupying a physical space within my listening environment, I am talking about spooky and very a satisfying experience. Details WAY in the background comes through in spades and imaging/sound-staging is Off-the-Charts! I am hearing the air between the bow and the Cello as it begins to swell and every note played from top to bottom is distinctly transparent, fingers between the fret of the Acoustic Guitar that captures re-verb, spatial cues, ambiance, tonality, speed, timbre, PRAT and the illusion of the very presence of these instruments occupying a three-dimensional space along with the musician.

This DAC has it all and Percussion Instruments as well as voices has the same attributes of sounding Life-Like, Natural, Organic or whatever term you use to describe, you have the feeling of being transported to the recording venue… 

You really begin to get a special appreciation for recorded music when you hear how a DAC like this SW1X Audio Design DAC II STD unravels the essence of the recording without altering the signal with up-sampling/over-sampling or applying filters. Implementing the DAC II STD into my system has been a revelation! I personally have never heard an Audio Note DAC and can only rely on those who have and the reviewer who has compared the DAC II side-by-side to the AN 2.1X and beat it, in fact, the DAC II held its own to the Uber expensive AN 4.1X and that says a lot about Dr. Slawa, Roschkow knowledge of circuit design, component matching and implementation, because the end result is all about the music…



Being that I was going to receive a Reference DAC, I wanted a cable that would not restrict but compliment the performance of the DAC II STD and decided to go with SW1X Audio Design Aero 10 which utilizes 100 % Silver in its SPDIF Cables; most claim 100 % Silver in their advertising but to discover it is silver-plated or the ground or return conductor is copper or plated and in my estimation is not 100%. My supposedly 100 % Silver SPDIF Oyaide DR 510 knocked off a more expensive and customized Silver Cable in the areas of sound-staging, imaging, detail retrieval and just a better sounding cable across the board and retails for $350+.

I was always under the impression that silver cables were bright, forward and analytical in their presentation but boy was I wrong. The Aero 10 is the best sounding Silver Cable I have ever heard and is in another stratosphere over the Oyaide. A very noticeable increase in spatial information, reverb, ambiance and detail retrieval is quite startling and at the same time sounds smooth, transparent, very organic and natural and this cable is not even close to being fully burned-in. From my cabling burn-in experience using a Audiodharma Cable cooker, it is at the 72-hour mark after removing the cable from the cooker when cable hits their sweet spot and I am needing another 48 hours to reach that point but will note more changes as the cable settles. Three days has passed since installing the Aero 10 and it is sounding beautiful, images are rock-solid and locked in place with a wide and deep sound-stage.

SW1X Audio Design has something special with their design and I believe that this is one of those DACS that will stay in your system for many years and the thought of chasing the latest chip will be quickly resolved upon powering up your SW1X DAC. This DAC and AERO 10 SPDIF Cable are “Highly Recommended”.


System Components:


Acoustic Zen Crescendo’s Loudspeakers

Don Sach’s DS2 6SN7 Tube Pre-Amplifier

Don Sach’s Kootenay 120 KT88 65 Watts Tube Amplifier

PS Audio Perfect Wave Transport

ModWright Marantz SA 8005 Tube CD Player (Current & Previous)

SW1X Audio Design DAC STD II

Equi-Core 1200 Balanced Power Plant




CH Acoustic X20 Power Cord

CH Acoustics X20 Anniversary Edition Interconnect

Teo Audio Ultra’s Liquid Metal Interconnect

Oyaide Black Mamba V2 Power Cords

Oyaide Tunami V2 Power Cord

Oyaide DR 510 Silver Digital SPDIF

Oyaide Tunami Nigor V2 Speaker Cables

Audio Design Aero 10 100 % Silver SPDIF

Gutwire Perfect Ground Cable

Audio Magic Blue Dot Premier Ground Disrupter


@wig Great review. Good things aren't necessarily big or expensive. Even so, oh for the money to upgrade mine....
wig congrats on your new DAC! I read about that on HFA also, love that site, one of my comments is at the bottom of the review page.  It looks like a great DAC and he obviously, and I an not saying this negatively, ripped quite a few idea off AN. He even has levels 1-3 and Special and Signature versions like AN. The DACs look like AN DACs and even have some AN parts. It's a recipe that worked for AN obviously glad you like it so much I was very intrigued myself! Happy listening!
Superbly written review, wig. Congrats on owning what I am sure is a top-notch DAC. Enjoy!

Congratulation, very well written review of the SW1X Audio Design DAC STD II DAC I

Thanks Guys!

It is a great sounding DAC and will only get better with more time, which is amazingly good at this point...

Wig :)

One thing to realize with this DAC, unlike the Border Patrol, is that you will hear the jitter of the transport. If you change cables, transports or treat the disk, you will probably hear differences. This is why you are liking the silver coax cable.

This is a good reason to consider a good reclocker like the Synchro-Mesh to reduce the jitter coming from your transport. Transport jitter is usually quite high:


Other advantages of the Synchro-Mesh:

1) Provides galvanic isolation of ground between transport and DAC. Eliminates ground-loops.

2) Upsamples 16/44.1 to 24/96, allowing the filters in the DAC to be more effective and providing a more analog signal.

3) Creates a perfectly matched impedance to a good 75 ohm cable. Surprisingly, most transports don’t get this right.

Even very expensive transports, many times the cost of your DAC will have high jitter compared to the 20psec of the Synchro-Mesh. For a minimal $699 investment, you can get much better imaging, slam, improved soundstage and less edge on vocals. 30-day money-back guarantee, less shipping. Some customer feedbacks:


Also, I though you already had my reference silver cable for $499. My customers have yet to find anything that beats it, at any price. I only designed this cable because they were spending $2K+ and not getting great results. These cables should ALWAYS be more than 1m in length. Mine are 4 feet. See my white-paper explaining why:


Steve N.

Empirical Audio

The jitter experts

Steve N,

This is an enthustiastic review for the SW1X DAC, please refrain from your insessant plugging of your own gear, it does nothing to add to the thread.
Steve N. has been booted-off another well-known audiophile forum for peddling his equipment. Don’t know how he gets away with it here,being Agon has a place to specifically advertise and sell audio equipment. He keeps referring to his sponsored forum as though it is impartial, to boot.
This forum doesn’t necessarily subscribe to the rules of other web sites. 

Congrats on your new DAC! Which one of your power cords are you using with it?

- X20 PC on Balanced Power
- Oyaide Tunami GPX V2 on Tube Amp
- Oyaide Black Mamba V2 on Tube Pre, PS Audio PWT and DAC II; all fitted with Furutech FI-50 Connectors ( 2 OEM & 2 non OEM).
Hi Wig
Congratulations! No doubt this DAC is just fabulous sounding and I’m very happy for you. Based on your description of the sound, it doesn’t seem you need to reclock anything 😊.
Your balanced power will be dealing with jitter quite happily btw.. Congrats Wig..
Your balanced power will be dealing with jitter quite happily
Will you please explain how balanced power has an affect on jitter?

My SW1X DAC STD II has been running constantly for over two weeks now and is sounding more refined and front-to-back and sided-to-side layering is extraordinary. I can hear distinctly, 5 different performers on stage within their own space with no crowding, blurring or congestion.

I know further improvements can be had with better tubes and waiting on some 1960 Foton Factory Square Getters 6N6P to arrive and will roll the rectifier with a Tung-Sol 6X5GT. This should be a magical combination...


Apologies, I only just saw your post re jitter and balanced power.

It is understood that by accurately balancing mains power any residual digital hash / reactive current will sum to zero ie common mode noise rejection. Equitech suggest a reduction in jitter of 30-50% in many cases just by using a good transformer which I can completely believe having been through this over the last few years. The sound from my own digital (Ayon CD-T & Concert Fidelity DAC040B/D) is far closer to my analogue front end via it's own dedicated 300va symetrical output transformer to the extent that I would say that digital really needs this to work optimally.

Some info from Equitech's Martin Glasband on the subject:



Received my 1960 NOS Foton Factory 6N6P tube recommended by Dr. Slawa for my SW1X STD DAC II and at the same time upgraded the Rectifier to a Tung-Sol 6X5GT and an already phenomenal DAC is now even better.  The midrange is richer/fuller and without sacrificing any detail but it is the imaging, sound-staging and layering to take note of; “Truly Holographic Palpable Dimensionality”…


@ david_ten

This is the best sound I have ever heard in my system in combination with Don Sach's DS2 6SN7 Tube Pre-Amp and Don Sach's Kootenay 120 KT88 Tube Amplifier; Simply Amazing!



Hi Wig,
It's refreshing and fun to to read posts from people who are genuinely happy with their audio purchases and system. I thought your DAC  was an upgraded model. What further upgrade options will you pursue? This DAC appears to be a long term keeper 😊 and that's good. 
@ charlesdad,

The upgrades will take an already phenomenal DAC even further with Audio Note Caps, Direct Heated Diode Tube Rectification and a slew of other parts that are harmonically matched; Way more refinement...

I am totally happy with the way it is sounding now but know it will get even better! Had a few others that bought this DAC with top shelf parts, told me they have never heard anything like this and were very happy with their purchase.

Wig :)
@wig That’s great news. In the meantime, looking forward to learning / reading about how your Verastarr cables are powering your happiness. : )
The Audio Note capacitors have a reputation for excellent sound quality. Directly heated triode (DHT) when properly utilized can yield fabulous sound quality.
@ charlesdad,

That is what I have heard and read about in regards to DHT and this may be my Christmas present in 5 months :)

@ david_ten

I was quite happy with my Nanotec 308 and Oyaide Black Mamba V2 PC until I tried Verastarr's and know have almost a full loom of Mike's cables and they have without a doubt elevated each of my components to an unbelievable level in terms of tonality, imaging, sound-staging, dynamic impact/slam with unbelievable realism...

@wig Congrats again on the new DAC glad it's providing you so much pleasure! Just to clarify is the upgrade a DHT output stage that's tube rectified? And I am certainly a fan of AN caps having an AN DAC I know they will sound amazing! Keep us posted on your upgrade Wig and congrats on the new cables as well!
Hi Wig,
I Reread your earlier post and realized that you were referring to directly heated "diode" (not triode) rectifier tube. Nonetheless I believe that you'll be very happy with the upgrade choices.
@ jond

That's correct, DHT Tube Rectified Output Stage but check out the link below that lists parts based upon your listening criteria:


Those foil cables are something special for sure.

@ charlesdad

Thanks again! I'm really enjoying my system like never before, Don Sach's Tube Pre-Amp and his Kootenay 120 KT88 Amp along with SW1X STD II DAC and Verastarr cabling keeps me up past midnight daily and this has been going on since March :)


Very cool. I’ve been a vinyl only guy forever, and only recently decided to introduce digital into my main system. I am very pleased with the Border Patrol and this looks like a real step up in the same direction, at what appears to be a fairly reasonable cost- the fully monty signature version at 3500 UK pounds (ex VAT)?
Hi wig,

Loved your review of the SW1X DAC. And I immediately looked it up. And I’ll be doing more research on it as I get the time. I am curious about the Aero 10 cables you mentioned. I can’t find the listed by that name anywhere. I found the company and links to copper or silver ic’s, but nothing called Aero 10. Can you put up a link please? Also, if I might ask, what are lengths and prices of them?

Thanks in advance.

Hi Wig,

Thanks for providing us with the great review, and congratulations on attaining this terrific milestone in the evolution of your system!

As a point of information, though, and not that it matters much, contrary to what is stated on the SW1X web page you linked to in your last post I’m pretty certain that neither the 5C4S full wave rectifier tube nor the 5687 twin triode output tube is directly heated.

For the 5C4S note the reference here to indirect heating, and also click to expand the second of the two datasheet pages shown to the right of the picture of the tube. The pin diagram shows a heater connected between pins 2 and 8, while the cathodes are connected just to pin 8. Another diagram shown here, as well as this datasheet which is the pdf linked to on that page, indicate the same thing. (The designation that looks something like 5U4C, although with the "U" looking a bit different, apparently is Russian for 5C4S).

Regarding the 5687, it is indicated as being an indirectly heated twin triode in various datasheets that are readily found, as well as in a vintage GE tube manual I have.

In any event, enjoy! Best regards,

-- Al

Post removed 
@almarg and @wig I think I see where the confusion stems from:
5C4S directly heated diode tube rectified CLC (choke filtered) tube output stage power supply 
Directly heated diode could easily be confused for  directly heated triode.
Hi Jon,

Yes, the wording is a bit ambiguous. However per the three references I cited in my previous post the 5C4S is not a directly heated diode. Those references indicate that it is indirectly heated, contrary to what is stated in various places at the SW1X site.

And the 5687 dual triode output tube is indirectly heated as well, as I had mentioned.

Best regards,
-- Al
P.S:  For an example of what the pin diagram would look like for a directly heated diode tube that is otherwise similar to the 5C4S see this diagram of the 5U4GB.  In contrast to the diagrams of the 5C4S I linked to previously note that no cathode appears in this diagram; there is just a filament and the two anodes/plates.

Best regards,
-- Al 
@ curiousjim
This is a very good sounding SPDIF, hand made with all silver, utilizing different gauges sizes and no screens to choke openness and transparency; I believe 1M at the time I bought was $500 USD based upon the exchange rate.


@ almarg and @ jond

We are grateful to have you guys on this forum, very knowledgeable and inspiring to many Audiophiles. I will ask Dr. Slawa about his Direct Heated Diode Tube Rectification, maybe he has something up his sleeve and is brillant :)

@ in_shore

I actually tried the SM with his upgraded PS and it elevated my Modwright Marantz SA8005 Tube CD Player to a higher level but when added between the DAC/Player, it stripped the organic nature of the DAC, making everything sound flat. Maybe the SM does not complement NOS DACS.

@ whart

The BP is an outstanding DAC and very musical, the SW1X takes it much further...

@wig Thank you kindly for the nice words.

Regarding directly heated vs. indirectly heated rectifier tubes, the following article strikes me as being informative:


Although I can’t vouch for the following statement one of the authors provides, given the knowledge that is evident in the rest of his posts I would consider it to be worth considering. The words in brackets are mine:

IMHO, directly heated rectifiers like 5U4 have a “faster” more “transparent” sound with a lot of punch, speed, and dynamics as compared to a Mullard GZ34 [which is indirectly heated]. The legendary GZ34, though, has a much more refined, more “hifi” sound with smoother treble, warm detailed mids, and less edgy sonics than directly heated types like 5U4. I tend to favor the indirectly heated rectifiers ....

Some of the other issues he mentions involving the choice between the two types of rectifiers, such as the potential for cathode stripping in the audio tubes in the case of directly heated rectifiers, are non-issues if they are addressed properly in the design.

Best regards,

Hi wig,

Thanks for your reply.  I'm finding the website,  but still no finding the Aero 10 ic's.  Guess they changed the name.  I'll have to email them and find out.

Thanks again


Instead of upgrading my SW1X DAC II, I went up the line to an SW1X DAC III that I should have in 8 days or so.


Wig : )
@wig I look forward to what you have to say. Do you still have the DAC II in house for direct comparison?

also - this bit on their website is curious "Based on 2 x PCM56 K – the most refined and highest resolving sounding 16 bit DAC chips ever produced"

If that's true, why does the top of the line DAC III use TDA1541A instead??
@ k4rstar

The SW1X DAC II sounds fantastic and even beat an Audio Note, which is like 3 times the price.

That 1541 chipset is the most sought after chip ever produced and is no longer in existent except for those who purchased them many moons ago but are the best analogue sounding chipset and are typically used in manufacturer’s top DACS.

Will not be able to do any direct comparison since my DAC II is sold, but it refines the sound of the DAC II with another level of analogue naturalness and more signature parts.

Hi Wig,
Congratulations! Are you choosing the standard, special or the signature version of the level III DAC? The various part options available is quite intriguing.  For example you have choices regarding the decoupling output capacitors. .  In my Yamamoto DAC I replaced  the stock film output capacitors ( which were already good)  with Duelund CAST capacitors (superb) and the improved sound quality was undeniable and worth every cent. I bet your SW1X DAC level III will sound fabulous and look forward to your upcoming listening impressions. 
@ charles1dad

It’s a DAC III STD, which has some very nice parts and upgrades for this model was not necessary unless one wants the best parts in every location which could cost possibly more than the DAC itself.

I cannot wait to get this DAC in my system... : )

Congratulations Wig and looking forward to hearing your impressions on the new Dac it looks like a good one!