HoloAudio – May DAC

(19 customer reviews)

$4,198.00$5,598.00

Specs and General info:

Dimensions per chassis (2 total): 430 mm (W) * 300 mm (L) * 55 mm (H) additional 12 mm for machined feet (for each part, two of these chassis stacked on each other)

Weight: 18.0 kg Approximately for both Chassis or about 39.68Lbs

Power Consumption: 60W

Accessories included: power cord (NorthAmerica ONLY), remote control, DC Power Cable (1M length),   Package includes DAC only + Remote +DC Cable – NO Batteries in remote to speed up customs clearance. 

WARRANTY – 3 years warranty, both parts and labor, cover one way shipping (return shipping once product is confirmed a warranty claim). Be sure to buy directly from HoloAudio or authorized reseller and we recommend to buy from HoloAudioUSA<– this is KitsuneHiFi 😉 – Support is given from the source you choose to purchase from.

This is special order item (will show “in stock” if able to order, this means we have the parts available for this dac and the order can be placed), with a typical 5.5+ weeks (estimated) delivery time to USA customers.  However orders placed after Jan 1st 2021  (every year) may be delayed due to Chinese new year and add an additional 2weeks. This is out of our control.

Other voltage options than 110V (ie: 220/230/240V) may delay order an additional week. We will give you current estimate upon receipt of payment if it is different than the quoted 5.5+week estimate, and can be cancelled if you choose not to accept the terms to wait for the production/shipping times. After you accept the terms, I will place the order with HoloAudio directly, as the order is considered a special order item there will be no cancellations or refunds.  The product is guaranteed not to be DOA and has multiple levels of quality control testing before it’s shipped out to you. We are confident you’ll be happy with your purchase.

$5,598.00

In stock

KTE May DAC - Top Tier Model with all the options, hand selected dac modules, KTE exclusive Caps, HoloAudio Caps, Dac Module exclusive cover/shields, Enhanced USB Module w/Titanis 2.0 circuit, Silver wiring, Red Nano Fuse and many more mods/improvements. comes with remote, DC cable, USB Cable, power cable included only for North America.
$4,198.00

In stock

L1 (Level 1) May DAC - Base Model - does not have HoloAudio Caps, does not have KTE caps. Basic specs/components. Standard USB Module, copper wiring. standard Schurter Gold fuse. does NOT come with remote, DC cable, USB Cable, power cable included only for North America.
$4,798.00

In stock

L2 (Level 2) May DAC - Moderate spec'd version - includes upgraded HoloAudio Caps, does not have KTE caps. no dac module covers, Enhanced USB Module w/Titanis 2.0 circuit, copper wiring. standard Schurter Gold fuse. comes with remote, DC cable, USB Cable, power cable included only for North America.

Description

-May Dac = “The possibility of.”

The May DAC is here! over 3 years waiting and tremendous R&D to achieve a new level of performance and sound quality that sets a new standard. Ultimate endgame DAC. Natural Analog sound with no compromise. Having the best measurements of NOS R2R Dacs. And delivering our intoxicating sound signature that HoloAudio is known for.

Currently production time is estimated for about 5.5+ weeks from time you place your order. We appreciate your patience and understanding. We will likely deliver before this time, but this is an estimate for new orders. Inventory shown on the website is to control sales volume only.

 

Here at Kitsune HiFi, we have three versions of the May DAC. Below are the three levels, and KTE being our Flagship model with all options:

Prices are as follows for May lineup:

L1 MAY = $4198.00 + S&H 

L2 MAY = $4798.00 + S&H 

KTE MAY = $5598.00 + S&H 

As of April 2020 shipping costs have gone up significantly due to COVID19. this is out of our control.

What’s the difference between models? For a quick explanation- go to the orange links found below the add to cart button.

 


Some noted features:

The May DAC (all three models) will also support DSD1024 native and PCM 1.536MHz output! Theoretically it can do DSD2048 and PCM 3.072Mhz however is untested at this time. Also, we have worked hard to reduce the common click noise with all dacs when switching from DSD to PCM. This sound click sound has been reduced significantly with a special circuit design. The May DAC has the new and exclusive USB Enhanced module (L2 and KTE ONLY) which has our FPGA with the new Titanis 2.0  and custom firmware to improve USB Eye Pattern and reduce latency to near zero as well as reduce jitter to very very low levels. The USB module has completely new code written to optimize performance and reduce latency significantly. Low frequency performance (-40db) is also improved. The “enhanced” USB xmos module is twice as powerful/capable as the one that is used in the Spring2.

New improved power supply circuit with high performance multi stage regulation circuit using Rubycon ZLH caps, Panasonic FC, Vishay Caps or L2/KTE models with our exclusive HoloAudio Branded Caps (KTE model unique custom proprietary caps to replace Vishay caps)

We are no longer using common LVDS chipset and are now using a custom 4way circuit that isolates each line which further improves sound quality. such as the MCLK is isolated from data line and this improves jitter spec. Also there are TWO i2s ports in the May dac. Each one can be individually configured pin outs to support all i2s products on the market.

The May and KTE version of the May DAC also is with a CNC machined aluminum remote control! Standard with all three models.

The KTE version has OCC copper wire replaced with 1.5mm pure silver wire. 1.5mm Silver wire is soldered direct to the pcbs with highest grade audio solder. Silver Rhodium Faston connectors used at IEC input.

The May is a DUAL mono DAC. so there is a dedicated Dac Module for Left Channel and a dedicated Dac Module for Right Channel. Also each channel is individually powered by it’s dedicated Otype FLATWIRE transformer found in all three models. We have found after careful testing this new transformer type outperforms ALL transformers we have ever tested to this date. Near zero leakage, improved dynamics and overall spectacular performance. They are handmade for this dac specifically and delivery world class performance you would expect.

May DAC also has a new screen on the front that appears the same as the Spring2 on initial glance…. Font size is bigger than Spring2 but smaller than Spring1. Also you can see the CD track-time information is displayed when using spdif inputs!!!. This is done by extracting additional data from SPDIF. This a part of CD red book standard but nobody notices this and often forgets this cool feature or doesn’t know how to extract the data!. This will lead a fashion for other DAC developer to support this feature… customers will surely love this feature albeit subtle. The screen is much better contrast and viewing angles and one of the first things one may notice.

The May also has a front power button now! It’s been a request by many customers and gone are the days of a good old reach around to get the dac to be turned on! As mentioned before above… The DAC has a soft start circuit!! So don’t fret, it takes a moment for it to charge up and pull power without blowing the fuse!! It actually uses the same exact value of fuse that our Spring1 and Spring2 has! But two transformers! If we don’t have a soft start a couple issues can happen… one being a blown fuse from power surge, and another simply having possible pop noises. No chance of these things happening. We have carefully designed the circuit to have a zero compromise design.

Technical Information about our Custom PLL circuit:-

Now the May is implemented with femto clocks, and also new discrete ultra high performance voltage regulators. It has an advanced PLL (phase lock loop) circuit that is completely custom built for ultra high performance anti jitter performance. Even the highest levels of jitter are near eliminated which delivers world class performance. Using Crystek VXCO clocks that will take any incoming digital signal an reclock it to perfection! This feature can be enabled or disabled to test and prove it’s performance is truly spectacular. Note: this is NOT an off the shelf PLL, but it’s truly the most powerful PLL found in a DAC. Or at least to our knowledge it’s the most powerful PLL ever.. Spdif usually is a not a good protocol because it’s very old and dated! It was designed in 70s together with CD with Sony and Philips. As you may know, It encodes the data signal together with clock signal so it can be transferred by a one-core cable. It makes the cable easy to source, but to encode the data to clock at the transmit side and decode the clock from data at the receiving side, creates jitter. Toslink is a fiber glass version of Spdif. So Toslink adds even more jitter while doing electronic to photo and photo to electronic translation. So people will see clearly that I2S is usually better than SPDIF because I2S has 4 separate signal, 3 clocks 1 data. So it does not have encoding-decoding stuff thus has a better jitter performance. This is important to know this.
A common technique to improve the clock signal from SPDIF is PLL. A PLL is to use a local clock generator to track the source clock. You know jitter is actually a time deviation problem. For example, the fist period frequency is 44101Hz and the following second period is 44099Hz. Thus it has 2/44100 jitter. A PLL is to smooth the time deviation of clock. So after the PLL, it can be 44100.9-44099.1(this is a weak/poor performing PLL). Or it can be 44100.1-44099.9(this is a strong performance PLL). Usually, a SPDIF chip, like AK4118A, has an internal PLL. AK4118A is good chip compared to other Spdif receiver chip and it marks 50ps jitter. It’s the best we can get from a commercial chip. But it’s far from ideal, and definitely not enough for a HiFi standard we are implementing in the May dac. So we need a significantly stronger performing PLL. If the PLL is strong enough, it can smooth the 44101-44009 source clock to 44100.00001-44009.99999(very close to ideal 44100-44100)
But to make a stronger PLL is not easy, it’s actually incredibly difficult. First you need a powerful local clock source. A fixed clock can’t be used because it need to be adjusted to follow source clock rate. A common solution to use a VCO(voltage controlled oscillator). VCO is made by resistors, capacitor and inductors. The cost is low but performance is not so great. So, a better solution is to use VCXO(Voltage controlled crystal oscillator), it uses crystal as oscillator and crystal is a far better oscillator. The VCXO we used in May is Crystek’s CVHD-957. This the best VCXO we can get now.
The second hard problem is, the data need to be synchronized with clock. For example, the source has 44101-44099 clock from Spdif, that also mean it has 44101 samples in first period and 44099 samples in second period. So a good local 44100-44100 clock will have to throw away one sample in first period and lack one sample in second period. An easy fix to it is to use digital filter to smooth the data and it calls ASRC, but ASRC actually modified the data. So after ASRC, the data is modified thus not bit perfect anymore. And digital filter can also generate time domain problems like ringing artifacts. So, a digital filter is not a good way to solve this problem, or you can say, it solve a problem by introduce another problem.
May uses a fifo buffer to store the extra one sample in first period and release it in second period. So it has no harm to data. The difficulty for this design is how to manage fifo buffer. It can be a problem when you have a long-term jitter. And long-term jitter is actually called low frequency phase noise in a frequency domain point of view. To explain it easily, let’s take a example, a long term jitter can be like this, 44101-44102-44103-44104-44105-44104-44103-44102-44101-44100-44099-44098-44097-44096-44095-44096-44097-44098-44099-44100. So you see, it will have 25 extra sample in first ten periods, so the fifo buffer need to able store enough of them and release it in next 10 periods.
So, as a result, May’s PLL’s corner frequency is set to 0.05-0.1Hz in 3-orders. Than means it can reduce a 10s long term jitter by 90%, 1s period jitter by 99%, 0.1s period jitter by 99.9%…… That maybe the most powerful PLL in this industrial. And the most important is, it won’t lose data, it can still locking the source while huge jitter comes in. When you compared other similar PLL in the industrial, you can see it simply unlock the signal when huge jitter comes in. So, in that way, it simply stop you from listening, it tells you there is a problem but not solve it.
I have attached 2 pictures. The AP equipment generate huge jitters to SPDIF(750ns, 1KHz). If the PLL turned off, you will see an very ugly spectrum that means the jitter distorted the analog signal badly. The other picture turn on the PLL, and you can see it beautifully removed almost all the jitters. Compared to other competitors PLL. They won’t remove the jitter so clean, and simply unlock the signal for more than 10ns jitters.

 


More about the May Dac.

  • The new generation of linear compensation technology solves the accuracy errors caused by resistor
    tolerance, after compensation, reaching a variance of 0.00005% tolerance accuracy.
  • Proprietary anti-jitter technology that provides a full amplitude of anti-jitter without increasing noise floor
    and other undesirable effects.
  • Based on this new generation of technology May “梅” can provide a SINAD of >115dB and a dynamic range
    of >130dB, which represents the performance limit reached by today’s most advanced R2R architecture
    DAC.
  • Using the ultimate performance of PLL+FIFO technology, provides 0.1Hz Third-Order low-pass ability to
    inhibit jitter. It also uses a high-performance femtosecond VCXO as the PLL clock source. Under the premise
    of being almost immune to the front-end jitter, it can also lock up to 1.5us-2us @ 1KHz signal with high
    jitter. (It can lock up to 1.5us-2us @ 1kHz signal with high jitter on the premise of almost being immune
    front-end jitter).
  • Dual Mono DAC L/R channels are independently powered by their own dedicated transformer in the PSU
    chassis. This provides better channel separation and more accurate sound stage.
  • Official Support USB and I2S up to DSD1024 and PCM1.536MHz sample rate.
  • The USB interface uses proprietary firmware with ultra-low latency, a highly reliable data transmission, ideal
    USB eye pattern measurements that contributes to 2-4 times higher performance than official firmware.
  • Two sets of independent HDMI-I2S input interfaces are provided, and each set of I2S has a four-way
    independent circuit, as opposed to standard LVDS chip, making I2S clock signals subject to lower
    interference and lower jitter. In addition, each group of I2S inputs can be configured with specific pinout
    configuration, making it compatible with most of the HDMI-I2S digital devices on the market.

 

General info:

Dimensions per chassis (2 total): 430 mm (W) * 300 mm (L) * 55 mm (H) additional 12 mm for machined feet (for each part, two of these chassis stacked on each other)

Weight: 18.0 kg Approximately for both Chassis or about 39.68Lbs

Power Consumption: 60W

Accessories included: power cord (NorthAmerica ONLY), remote control, DC Power Cable (1M length),   Package includes DAC only + Remote +DC Cable – NO Batteries in remote to speed up customs clearance. 

WARRANTY – 3 years warranty, both parts and labor, cover one way shipping (return shipping once product is confirmed a warranty claim). Be sure to buy directly from HoloAudio or authorized reseller and we recommend to buy from HoloAudioUSA<– this is KitsuneHiFi 😉 – Support is given from the source you choose to purchase from.

This is special order item (will show “in stock” if able to order, this means we have the parts available for this dac and the order can be placed), with a typical 5.5+ weeks (estimated) delivery time to USA customers.  However orders placed after Jan 1st 2021  (every year) may be delayed due to Chinese new year and add an additional 2weeks. This is out of our control.

Other voltage options than 110V (ie: 220/230/240V) may delay order an additional week. We will give you current estimate upon receipt of payment if it is different than the quoted 5.5+week estimate, and can be cancelled if you choose not to accept the terms to wait for the production/shipping times. After you accept the terms, I will place the order with HoloAudio directly, as the order is considered a special order item there will be no cancellations or refunds if 48hours past date order was placed. The product is guaranteed not to be DOA and has multiple levels of quality control testing before it’s shipped out to you. We are confident you’ll be happy with your purchase.

NON USA/CAN customers please contact us for quote on shipping costs. Please include your full shipping address and phone number along with voltage requirements when requesting to order this DAC. The same terms apply and estimated production times quoted above. HoloAudio products are assembled in China and shipped out from HK. 

 

Shipping estimate varies, it’s best to email us for a current quote. (items in stock are NOT ready to ship, this means we have enough components on hand to build them. We are working our best to keep up with demands. You will get estimated time for production and shipping with your order. (Average is 4+weeks production and 4-6days shipping)

We sell HoloAudio Products and offer support to North America and Japan, Other areas you must contact you local dealer. More information can be found below:

 

To place an international order with us (other than HoloAudio products, please ask if we are able), USE our contact form… and then please provide the following information: Full Name, Phone Number, Shipping Address, Email Address to send Paypal Invoice to, and detailed list of products you would like to order and voltage requirement if applicable. But if you are in North America, just use our website and add item to your cart and checkout as normal. Other Areas must contact your local dealer.

For HOLOAUDIO sales, please contact a dealer near you.

If you are in Europe or other areas nearby, please contact our European Authorized HoloAudio Dealer for the best service and support in your area, Magnahifi.com

If you are located in the UK, please contact EliseAudio

If you are in South Korea, please contact our dealer in South Korea – SonorisAudio 

If you are in HongKong, please contact our dealer WildismAudio – WildismAudioHK

If you are in Australia, please contact IndiHifi.com.au, your source for HoloAudio in Australia


 

 

“NOTE: Be sure to say in notes what volt ac model you need, USA/CAN is 110 volt ac standard etc.  – Also note if you ask for special voltage transformer that it can delay your order up to a week longer.”

Kitsune HiFi carefully chooses products that we want to offer to our customers and be unique and/or stand out from all these audio supply stores. Jeff Zhu is a very talented engineer and is the brains behind HoloAudio. Some say he is the man behind the curtain and he has certainly impressed us with his knowledge and his newest line of products that surely will leave you impressed too! The May DAC is the most recent product and is capable of DSD native on an Discrete Resister Ladder DAC!  This May DAC is capable of DSD1024 native and actually running on his bespoke discrete ladder DAC! This is a unique custom build discrete resistor network DAC with linear compensation and advanced architecture based on R2R however we don’t refer to it as R2R since the design is far superior. This is our second discrete DAC that has linear compensation and this allows for ultimate music reproduction accuracy. Dual MONO R2R DAC Module resistor network with advanced architecture for PCM w/Linear Compensation. Also Dual Resistor Ladder network with optimized architecture specifically for DSD! We will be offering the first May DAC’s in the USA and the KTE/Kitsune Tuned Edition is no longer just exclusive to us. We have licensed the build as being the ONLY authorized modded edition of the May DAC by HoloAudio. This means our authorized dealers will carry our KTE May! And if you buy from a dealer you will get support from that particular dealer. Many may continue to choose Kitsune HiFi and will receive our excellent customer service that we are well known for.

You may be asking… well what is so special about this DAC? A Discrete R2R DAC with linear compensation…what is this?

There’s an additional R2R resistor network in the May DAC, that compensates the main R2R ladder. It works like trimming, but trimming is to change the resistor value. This additional R2R ladder is digitally controlled and will accurately compensate the resistor tolerance reaching a variance of 0.00005% tolerance accuracy. . For example, the MSB of 16 bits should have the value of 32768, but due to tolerance, it represents 32700 in real world results. Then that additional R2R ladder will compensate 68 into it. Thus it now becomes 32700 + 68 = 32768.  What this means is that it’s likely the most precise Discrete DAC on the market with near flawless linearity, lowest THD and highest SNR of any NOS DAC. The sound is simply something you must experience to fully realize how special this DAC is. It’s a patented technology exclusive to HoloAudio. KitsuneHiFi is also HoloAudio USA and proud to bring you this DAC.

Product Description:

This new DAC “May” is the design of a new generation, it’s HoloAudio’s finest technology all designed by Jeff Zhu, the engineer behind these great products. It’s a full discrete R2R type of audio decoder and does not have off the shelf-DAC chip! This is a bespoke custom-designed core DUAL MONO DAC modules that are truly a breakthrough with technology for any DAC chip today. The May is here to achieve new heights, new dynamics and simply a full spectrum of audio to please the aural senses.

May DAC was carefully implemented with some of the finest components.
KTE May Dac images: 
[metaslider id=”6718″]
The following is added to KTE May:

1. 100VA DUAL O-type(not Toroid) FLATWIRE (NOT roundwire) 6N Copper custom hand made audio transformers. (All models)
2. All copper wire is replaced with 1.5mm pure occ silver wire. Only KTE model
3. Hand Selected Dac modules to have best measurements compared to averages. Higher dynamic range. Only KTE model.
4. CNC Black/Copper shield DAC Module Covers on each module with laser etched KTE logos. Only KTE model.
5. Replaced IEC inlet connectors with pure silver/rhodium plated faston connectors at the IEC inlet Only KTE model.
6. Fuse is upgraded with world class Red Nano fuse with gold/silver and graphene and quartz filtering materials. Only KTE Model
7. Standard Vishay caps are replaced/upgraded with KTE capacitors***
***unique ONLY to MAY KTE – KTE Caps to replace Vishay on the L1/L2
models (we have done extensive testing and these prove to provide intoxicating voicing and are beyond subtle improvements over L1/L2)
8. Custom made HoloAudio 1000V 1uF caps (replaces standard mundorf evo silver/gold caps)
9. Enhanced USB module with Titanis 2.0 circuit
10. Special Kitsune Tuned Edition branding inside and out (pure copper Kitsune fox emblem on top panel) + remote control / KitsuneHiFi VIP service, english support and manuals/software

Note: all models share/include same Flat wire Otype transformers, custom PLL with crystek vcxo clocks, all copper and black chassis color, remote control, dc cable, ac cable. These are the shared features.

 

DSD is natively supported on this Discrete Resistor Ladder DAC

HoloAudio is the world’s first to support DSD natively on Resistor Ladder DAC, so far the only one. This is not the DSD converted to PCM before digital-analog converter, but directly by the discrete components of the DSD digital to analog converter. Supported currently on MAC (DOP)and Linux (DOP), and Windows/PC (Direct Native and DOP). Please note, the word ‘R2R’ is the name of a kind of architecture of resistor ladders. This architecture requires less resistors yet still is capable to deliver more than acceptable performance. Most DACs in the industry use this architecture. The DSD Dac module resistor network of May Dac does not use R2R architecture for the DSD, more specifically it uses a very specific architecture which is optimized to perform DSD data to analog. So to be entirely accurate the DSD part of May Dac is using resistor ladders, not R2R..

Info on Red Nano Fuse type used in KTE May model:

Single crystal nano fuse
Specification: 5X20mm @2A(220v) or 4A(110v)
Withstand voltage: 250V (T) slow speed
Features: This product is complicated in process, special materials can not be made, this fuse is 100% pure handmade!
Tip: Input in different directions, the tone is different. Can try different directions
This fuse structure is relatively complicated, it is handmade, so the cost is not cheap, the structure is crimped, the contacts are firm and reliable, plated 24K gold, non-chemical gold. The fuse is made of imported single crystal silver-copper alloy. After nano-processing, note that the fuse is directional after nano-processing. The inner filling of the quartz sand is filled with nano-graphite, and the graphite has ultra-high conductivity and high anti-interference characteristics. The sound is beautiful, soothing and strong in layering. This is the flagship
product of high-end fuses so far.
Fill the fuse with 2 heads of quartz sand for good shock absorption and arc extinguishing. In the middle is graphene, which has the advantages of ultra-high conductivity and anti-interference. The fuse is a single crystal silver-copper alloy containing 10% precious metal, treated with nanographene, and stranded with a single crystal silver.
The fuse cap is stamped from 99.99% 4N copper, one end is plated with 24K gold and one end is plated with sterling silver. Increasing the conductivity and the speed of the power supply make the fuse and the socket highly accessible.
The fuse is firmly pressed by a large one and two small caps made of 4N copper. This process protects the fuse in the middle of the fuse. The fuse and the cap are in good contact and the contact is firm, which can prevent the microphone effect. Reduce the oscillation of current passing, making the sound quality more pure and the image more stable.
The inside is filled with two quartz sands, and the middle is filled with nano graphene. Graphite has super high conductivity, high anti-interference and other characteristics, and the sound is beautiful, soothing and strong. It has great benefits for sound quality and security, but it can only be handmade.
The ceramic tube has anti-resonance and eliminates the effect of the microphone sound.
The fuse is made of a single crystal silver-copper alloy, and a very fine single crystal silver wire is wound to correct the sound. After nano-treatment, it has excellent two-end extension, transient response, dynamic and musical sense.

Fuse Type for L1 and L2 May :

Shurter Gold fuse type

2A SB 5x20mm (220v) and 4A SB 5x20mm (110V)

May’s input and output interface:

  • Digital input interface includes
  • Enhanced USB (ground isolation) + Titanis 2.0 circuit + KYCON industrial High retention USB Connector (improved impedance spec) – Proprietary inhouse firmware w/ ultra low latency performance. Ultra low noise voltage regulation
  • RCA coaxial
  • BNC coaxial
  • AES/EBU
  • optical fiber/Toslink
  • I2S (HDMI) – improved ultra high performance 4way custom circuit (NOT traditional LVDS chip anymore) backwards compatible
  • I2S-2 (HDMI) – improved ultra high performance 4way custom circuit (NOT traditional LVDS chip anymore) backwards compatible
  • All digital input interface supports DSD (DOP mode).
  • Analog Output interface: single-ended, balanced.

May DAC R2R structure and design + Input/output Stage

Modern and popular delta-sigma type DAC differs from R2R within one clock analog value can recover a sampling point, and the delta-sigma is used to represent an analog signal after passing through oversampling and high-speed digital switching 0 and 1. In comparison, the conversion structure of R2R is most direct and pure, but delta-sigma is essentially a digital chip, high-speed digital signals 0 and 1 switch to the low-pass filter to process the analog signal and this process is prone to various problems, produce digital sound (digititus) and also in the super-sampling process will inevitably cause some ringing and distortion. But DAC R2R structure requires high-precision resistor network which the cost can be very expensive. And the digital delta-sigma DAC chip in comparison is very low cost. Patented R2R technology. This is the first discrete DAC that has Linear compensation and this allows for ultimate music reproduction accuracy. Dual R2R ladder network with advanced architecture for PCM, and Dual Resistor Ladder network with optimized architecture for DSD!

I/O stages: There is an Op Amp used for input stage and discrete component used for the output stage. The discrete output stage is working in pure class A.  It’s BiPolar Junction Transistors, direct coupled. 

A common question we get…” Why do you use an Op amp at the input of the DAC?”  

The input stage with an opamp is a good choice. It has a paired transistor input by the nature it is manufactured. But an opamp for the output stage is limited due to it’s size and the thermal capability. Also, no one will offer an opamp with class A output as it’s efficiency is so low. So an opamp used as input and discrete output combined together will have an advantage. It doesn’t mean that all discrete is not good. Actually, if we need to achieve enough low distortion. It needs at least 30-40 transistors. Which not only will it be huge and waste of space but it will also be too costly. I mean, to beat the opamp’s performance, a simple discrete architecture is not possible, although an all discrete design looks beautiful.

We use opamp+discrete architecture for the amp parts of May. Opamp is used for the input stage, discrete is used for the output stage. All the transistors in the opamp are in the same die, then it is matched by nature. This is key because by now, there are few choice for low noise matched pair transistors but an opamp has plenty of them inside. The Output stage is discrete because it generates a bit of heat. We need a class A output stage. So you can see May is very hot compared to other DACs. An opamp output simply can’t handle that power.

The true balanced DUAL MONO circuit design

XLR is using all of the circuit and RCA is just using half of them. The balanced output has better performance (THD, noise) and also better common mode rejection rate. If you’re listening environment contains interference, either from AC power or from EMI/RF then you will find a full balanced system can really help significantly.

With diverse and flexible sampling mode conversion mode

1: NOS mode: has no digital oversampling, the raw data is directly converted to analog.  Because digital oversampling will produce time-domain distortions, such as ringing, NOS avoids these problems. Generally NOS mode’s other performance indicators have a significant impact, but the Spring 2 is designed to allow top performance while in NOS mode.

2: OS mode: PCM is over sampled to PCM at a higher frequency, DSD is over sampled to DSD at a higher frequency, and then digital is converted to analog.

3: OS PCM mode: in either PCM or DSD the data will be oversampled to PCM and then digital is converted to analog.

4: OS DSD mode: in either PCM or DSD the data will be oversampled to DSD and then digital is converted to analog.

 

What are the May’s sound characteristics? :

One of the strong points of the spring is the spatial sounds stage presentation. It’s very wide and precise. It never sounds congested like many DACs. The high end is very detailed and never harsh sounding. It has the R2R goodness that many have come to know and love. R2R has almost a cult like following and this DAC will surely become a sought after DAC.  Everything comes effortlessly for this DAC. Bass is layered and textures, quite full and present without ever masking over the sweet mid tones that are produced. One special thing about the May is its amazing voltage regulation circuitry that better than 0.2uV output noise! This along with the FLATWIRO-core transformer helps regulate the purest power which translates to audio clarity and accurate reproduction. It must be heard to appreciate and come to love its sound. If you must have the best and nothing compromised then we would suggest the KTE or Kitsune Tuned Edition.


UPGRADE to a May Dac of any Level when you trade in your HoloAudio Spring version1 & Spring version2 (any level)

Find out more about this Trade-In Program – go up to the add to cart button, and scroll down a bit til you see all the orange links. these are all the important common links for this dac…like downloads, review, trade in program info and the differences explained between each Level.


 

Tim & Dawn Connor – HoloAudioUSA and KitsuneHiFi

We operate under strict business ethics and principle values. Our company motto we are always proud to mention to our customers, “Time will tell…” and this means that our products will earn the respect in a matter of time once people get their chance to test it themselves. Many companies need fancy buzz words and marketing to sell their products, we truly only need our customers to try our products and share their experience with others. Word of mouth is how our business thrives and we have many happy customers! We encourage others to try all the competition in the market and directly compare and see what type of value you are receiving. We are confident in our products and know that in time, our products will sell themselves once people get a chance to try them.  We offer tremendous value and quality without sacrificing on performance.

jeffzhu5

Jeff Zhu – HoloAudio  – founder/engineer

Jeff Zhu is the man behind this engineering achievement. Below are some comments that have been shared by Jeff to better explain this DAC in his own words.  HoloAudio is founded by Jeff Zhu and the USA division was a partnership formed with Tim Connor and his wife, Dawn Connor.

 

A little note from Jeff:

Many have asked about how does a discrete resistor network accurately reproduce sound. This email is a good read for those who want a technical explanation on how Jeff was capable of achieving flawless linearity and ultra good specs on THD. This was a reply to a customer who had a technical question about resistors and their limitations.

“About the resistor tolerance, his word is partly right, but not accurate. The MSB of 16bits value only represent 32768, not 65536, all 16bits is 65535, but the MSB is only 32768. There are techniques to reduce this requirement. For example, segment+R2R, using segment into the first few bits, then r2r for the rest of them. Rockna is segment+R2R, TotalDAC is all R2R. And you can see, Rockna’s THD spec. is much better than Total. Total uses foil resistor, but they used the simplest architecture. That results an unsatisfied test performance. To my opinion, it’s some kind of wasting foil resistors. Soekris also uses segment+R2R. MSB’s old model is all R2R, but I don’t know about their new models.

Anyway, There are ways to improve the performance, the segment+R2R is one way. Trimming is another way. There is an additional R2R ladder in Spring, it compensate the main R2R ladder. It works like trimming, but trimming is to change the resistor value. This additional R2R ladder are digital controlled and is to compensate the resistor tolerance. For example, the MSB of 16 bits should have the value of 32768, but due to tolerance, it represent 32700 in real world. Then that additional R2R ladder will compensate 68 into it. Then it became 32700+68=32768.

Actually there are other ways to improve performance, I just told you two stories. There are more stories behind the design. It is really hard. I must count every via holes in layout, every PCB wire has it’s impedance and must put attention on it. A via hole can be 50 m Ohm, it is 1/20000 of 1 kilo-ohm, and you see, it covers 32768 which is the MSB of 16bits. Also the switches has self-impedance which is about several ohms to 30 ohms. If you find this issue. Maybe you will go crazy, it seems to be an impossible mission. But a good designer will overcome all these problems. It’s our value at HOLO Audio.

All the resistor tolerance, switch impedance, line impedance, via hole impedance, finally reflect as linearity. There is a chart that shows Spring’s linearity, it’s excellent. But I suggest you to look at THD performance. Bad linearity must result a bad THD performance. But good linearity doesn’t mean there will be good THD performance. THD is dynamic performance, more critical than linearity which is a static performance.

If you look at the THD performance, you will find Spring to maybe the best among those competitors. I’m applying a patent which contribute a lot of that performance. But I can’t tell you how. It’s confidential now.

Best Regards

Jeff Zhu”

And another note on Linear Compensation. As Some have asked what happens when the Resistors values change over time? Jeff responds:

No matter it is a digital switch or analog switch, they are built by transistors, can be either bjt, mosfet or jfet. They have self-impedance call Ron(impedance when at on state). If we expect a lower Ron, the a bigger transistor is needed. But bigger transistor has bigger self-capacitance that will cause switching speed to be lower. So there is no perfect components in the real world.

About long term drift, the modern resistor technology has made it much better than older process. But the most important thing is, we don’t care absolute drift, we only care relative drift. That means, if all resistors are drifted in the same direction and same speed. Then it will be no impact for this application. So, we make sure to use the same batch of components in a single board. That will minimize the problem causing by long term drift.

As I mentioned in the earlier email. Spring is not using trimming, but using compensation. Not matter it is trimming or compensation, their goal is same, to make the resistance much more accurate so the linearity and distortion can be improved a lot.

Best Regards
Jeff Zhu

Also, another customer asking about the oversampling, Jeff replied and has some good information to those who are curious.

The oversampling is done by AK4137, ‘OS PCM’ converts the input stream to PCM no matter it is PCM or DSD, then send to DAC. ‘OS DSD’ converts the input stream to DSD no matter is is PCM or DSD, then send to DAC. ‘OS’ over-samples the input stream. If it is DSD input, it over-sample to DSD256. If it is PCM input, it over-samples to PCM384K or 352.8K ‘NOS’ does no oversampling. send the input stream directly to DAC module. About DSD ‘native’, it is the way the USB transfer the stream. You know DOP, which is DSD Over PCM. DOP put the DSD into a PCM stream. At the receiver end, it just unpack the PCM stream and get the DSD back. DOP does NOT change any bit of DSD stream, just sending it with the package. So it waste some data rate. At the same data rate, DOP is 1/2 of DSD native, the other 1/2 is the package. So DOP and DSD native are all bit perfect. The DSD stream sending to DAC is all the same. So, now you should know, DSD native is just about the way it transfers the stream. Not describing the way it does digital to analog conversion. At the DAC stage, the DSD stream can convert to PCM then do the final digital to analog conversion. Actually, most DAC chips do this inside the chip. One point needs to be remembered, DSD streams can’t do volume attenuation. If this chip can do digital volume control under DSD mode, then is must converted to PCM already. Let’s go back to Spring. If Spring works in ‘NOS’ mode. There is no
oversampling, no conversion, just the original data doing the final digital
to analog conversion. I will not explain how it does PCM conversion, you
should already know quite well about it. There is a lot of resistor ladder
DAC, they are born to do this. I just explain how Spring can do ‘discrete
DSD conversion’. Actually it is like DCS and CHORD. If you looking to DCS
and CHORD’s PCB, you will find ‘discrete DSD conversion’ is also using
switches and precision resistors, like resistor ladder DACs. So, no matter
it is ‘discrete DSD conversion’ or ‘discrete PCM conversion’, they all use
the same discrete devices. Just work in different architecture. That makes
possible to combine these two modes in one device.

Best Regards
Jeff Zhu

Our products are CE Certified for the European Market

 

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