Holo Audio Spring R2R DAC

[greenkiwi]

@bimmer100 I'm curious if you'd responded to the question about it being fully balanced or just inverts the signals somewhere after the DAC stage to get XLR outs.

 

[Peaceofmind]

If the Holo DAC circuit is not fully balance then the SQ of the single ended and balance out should sound the same. If the DAC is a fully balance design then the balance out will have the edge, of course your preamp and amp should also be fully balance to realize that SQ improvement.

 

[bimmer100]

I am sure the circuit is truly balanced, I believe the comment about XLR being better than RCA is from the Designer and was in reference to how it handles DSD on the outputs.  I've actually sent an email to Jeff to clarify on this. But otherwise, the output stage specs are as follows: This is THD, not THD+N.  The specs on website for THD+N are 0.00068% for PCM, and 0.00050% for DSD
 

Analog Output
THD 0.00030%
SNR -126dB
Voltage Output 2.5Vrms(RCA), 5Vrms(XLR)
THD 0.00020%
SNR -120dB
Voltage Output 1.25Vrms(RCA), 2.5Vrms(XLR)
Output Stage type	discrete Class A -  Bipolar Junction Transistors. direct coupled. The big MKP Cap in output stage is actually for power supply and not for signal coupling! Output impedance is 200Ohm.

[td=rowspan:3]PCM 48k NOS[/td] [td=rowspan:3]DSD 64X[/td]

 
To add a bunch of circuitry just to get a balanced output generally adds extra noise to the output, so these measured figured are quite low. HoloAudio's motto is "time will tell" sooo here we go.. I will update soon with an answer from Jeff @ Holo. 
 
He's been quite busy the last couple days but will get an answer from him as I'm sure he'll be able to answer this question a little better than I.
 
a quote he made in a previous email...
 
"      You are right, NOS is suggested as there will be no SRC. In the new firmware, DSD512 will run in NOS mode automatically. no matter what mode you selected in control panel. Because DSD512 is greater that the SRC chip’s DSD256 capability. So only NOS can be used.
 
         Also, I suggest to use Spring’s balanced analog output. It is better than single ended. Especially for DSD, balanced output is strongly recommended.
 
Best Regards
Jeff Zhu"

 

[Tboooe]

Hi guys...I apologize if this has been covered but I didnt not find the answer when searching this thread.  
 
What is the native file format for the Spring DAC?  I am not sure if I am asking this right but in other words, what does the Spring DAC convert all incoming signals to before processing at the output stage? Sample rate, bit depth, DSD or PCM?
 
I am asking because I would like to compare sending the Spring DAC whatever its native file format is from HQ Player with letting the DAC do its own internal conversion.  My previous experience has shown that moving as much of the computing from the DAC can yield some positive sonic improvements.
 
Thank you!

 

[bimmer100]

  Hi guys...I apologize if this has been covered but I didnt not find the answer when searching this thread.  
 
What is the native file format for the Spring DAC?  I am not sure if I am asking this right but in other words, what does the Spring DAC convert all incoming signals to before processing at the output stage? Sample rate, bit depth, DSD or PCM?
 
I am asking because I would like to compare sending the Spring DAC whatever its native file format is from HQ Player with letting the DAC do its own internal conversion.  My previous experience has shown that moving as much of the computing from the DAC can yield some positive sonic improvements.
 
Thank you!

 
I'm not sure I fully follow what you're asking, but depends what mode you are in. My favorite, personally, is the NOS mode. As it's pure and no OVERSAMPLING is done. As even though the SRC in the spring is good, i still prefer purity.  So some users are using the MicroRendu and HQ player to send DSD256 or DSD512 to the spring over usb.  And some users are using the SU-1 with the Spring and sending DSD256 via the i2s hdmi port (psaudio standard)
 
two sections of the dac, one discretely processes PCM, the other processes DSD (not a conversion) and similar to the HQ player hardware demo but on a scale of improvement of many multitudes.
 
I assume you are asking if you can do oversampling on HQ player....yes. 
--------------------
 
 
DSD is natively supported for the first time on this R2R Discrete DAC

HOLO Audio is the world’s first to support DSD natively on R2R 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 and Linux, and soon to be Windows/PC. Evaluation driver for native DSD512/256 here - the final windows 10 signed driver is due for release in October.

 

Spring’s input and output interface:

1. Digital input interface includes
2. USB (ground isolation)
3. RCA coaxial
4. BNC coaxial
5. AES
6. optical fiber
7. I2S (HDMI)
8. All digital input interface supports DSD (DOP mode).
9. Analog Output interface: single-ended, balanced.

Spring 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 network for PCM, and Dual R2R network 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.  The output voltage is 2.5 Vrms for single ended output and 5 Vrms for balanced output. The single ended is RCA. Balanced is XLR. They both use the same output stage. It's Bipolar Junction Transistors, direct coupled. The big MKP capacitor you can see in output stage are for the power supply,  not for signal coupling. And the output impedance is 200Ohm.
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 manufacturing. 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.
 

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 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.

 

 

[TimeLord]

I am sure the circuit is truly balanced, I believe the comment about XLR being better than RCA is from the Designer and was in reference to how it handles DSD on the outputs.  I've actually sent an email to Jeff to clarify on this. But otherwise, the output stage specs are as follows: This is THD, not THD+N.  The specs on website for THD+N are 0.00068% for PCM, and 0.00050% for DSD

Please don't take this post in any other way than how it comes across to a potential customer.

This product is not very well known; it does not have much of any reviews other than an impression or two. We are depending on getting solid facts to make an informed choice.

At the moment you are the only one providing answers by directly communicating to the manufacturer. It does not instill confidence in a potential customer when you are making available upgraded versions of the Spring, but you do not know basic design criteria such as whether or not the circuit design is balanced.

How did you consider what impact the Jensen caps or modified transformers would have on the circuit design?

 

[mtoc]

                                                             fully balance

 
little tip: AGD m7 and CH Precison c1 are the only two DACs that suit your standard.

 

[bimmer100]

Please don't take this post in any other way than how it comes across to a potential customer. 

This product is not very well known; it does not have much of any reviews other than an impression or two. We are depending on getting solid facts to make an informed choice. Our motto is "time will tell..." so in time all will be revealed. We have many demo dacs being sent over to be sent off to the list that is well over a dozen reviewers now. 

At the moment you are the only one providing answers by directly communicating to the manufacturer. It does not instill confidence in a potential customer when you are making available upgraded versions of the Spring, but you do not know basic design criteria such as whether or not the circuit design is balanced. 

How did you consider what impact the Jensen caps or modified transformers would have on the circuit design? Jeff suggested many of these mods, but they were too expensive for the original design. He wanted to make a dac that was affordable to everyone

 
 
No offense taken,
 
I'm a rep for the USA, not the engineer.
 
All these mods are done over in Hong Kong with an engineer that directly works with Jeff Zhu too. These "level2" dacs were tuned editions of the original design done by our tuner, and this Kitsune Tuned edition is one step further by the same person who implemented the Jensen caps. Jeff Zhu is directly backing what we do, as we are Holo Audio USA. KitsuneTuned is a company my wife and I run for selling Audio Gear and DIY Products etc. A new company as well. Yet Holo Audio has been around for a while longer actually.
 
So yes, I understand your skepticism of a new company coming out with a product that makes many claims. But as our motto states "time will tell.."  is a saying that in time all will be revealed. Many people will review the dac and more light will be shed on what we are offering. I'm confident in saying that the majority of people will be very pleased with this Dac and I expect a small amount to heavily criticize a new company like us.  I'm doing my best to sell the product here, and our team in HongKong has the brains behind all of it. So I apologize for not being able to answer all questions with a direct answer. I work directly with Jeff Zhu, the designer and if you need proof, that can be arranged as well.
 
 
 
We have products like the Mammoth Amp, the Sabertooth DAC PCM1704UK based....
 
and the mammoth we also have tuned versions with jensen caps
 
we have a USB reclocker cleaner product called "titanis" and it's actually quite good! we will be bringing these to RMAF
 
The Megaladon is a linear PSU for small PC or Laptop
 
the newest dac in the works is the "May" dac and will be priced in the range of 3-4K and be even higher spec than the Spring Dac.
 

-----------
My point is that we have many products and we'd like to be accepted of course, and expect to get a critic once in a while. But we are like the new kid on the block in the USA. I'm representing HoloAudio USA because we believe in the products that Jeff Zhu designs. So offering a more tuned version of the Dac and selling it under our Name was for the US market and needed branding to distinguish from some other companies who are trying to tune the dac without Jeff being involved. We have had this dac measured and posted the specs, and plan to even have it put on the APx555 for a test too. specifically the KitsuneTuned Edition. 
 
We will be at RMAF for those who would like to listen to the dac on a Headamp BlueHawaii SE.
 
Ted @ nativedsd.com has one of our dac's and so far is very impressed. His review will be up before RMAF, so have patience on this. We have more demo dacs going to go out...some of you are posting in this thread will have a demo dac sent to you. We want the dac to do the talking mostly, as it's truly about the music and how well this gear and deliver that music.  
 
Hope you'll give me a bit of slack now that you understand i'm NOT the engineer behind the tuning.  It's our company that has worked directly with Holo for our own higher spec model specifically aimed to the USA market. that's it. And imho, it makes sense to have a higher spec build for our market.

 

[TimeLord]

bimmer100 I did not want to quote your entire post, but that was very helpful. May I suggest putting the information about the tuning and the collaboration with Jeff prominently on your website? I am very interested in this DAC and information like that helps a lot since there are far too many people in this field that make claims about everything under sun making improvements about the sound.

Knowing that the design engineer would have opted for the upgrades, if not for cost considerations, heavily tilts my opinion on the matter. Of course hearing it will be the ultimate test.

When you make demo units available for folks on this thread, I would ask to be amongst them. I'm currently looking for an excellent DAC to complete my signal chain. It'll be paired as follows:

FLAC from PC--> Schiit Wyrd--> Spring --> Cavalli Liquid Gold--> Focal Utopia

I look forward to more impressions and reviews and thank you for the detailed response.

 

[bimmer100]

bimmer100 I did not want to quote your entire post, but that was very helpful. May I suggest putting the information about the tuning and the collaboration with Jeff prominently on your website? I am very interested in this DAC and information like that helps a lot since there are far too many people in this field that make claims about everything under sun making improvements about the sound.

Knowing that the design engineer would have opted for the upgrades, if not for cost considerations, heavily tilts my opinion on the matter. Of course hearing it will be the ultimate test.

When you make demo units available for folks on this thread, I would ask to be amongst them. I'm currently looking for an excellent DAC to complete my signal chain. It'll be paired as follows:

FLAC from PC--> Schiit Wyrd--> Spring --> Cavalli Liquid Gold--> Focal Utopia

I look forward to more impressions and reviews and thank you for the detailed response.

I will ask Jeff for a statement on the matter. He is very transparent and honest. A man with many good principles he lives by and designs by. Also extremely ocd when it comes to circuit design one of my favorite things about him. He isn't about to disclose everything about his technology but he does what he can to disclose as much as possible so you know what you are getting!

But I suggested some of these mods for an exclusive version for the USA market and we agreed on having them done without compromising his careful implementation of the DAC. They indeed improve upon its sound. As we have tested a lot of a/b between the different levels of dacs. anyhow, I will follow up soon. thanks for your patience and understanding we want happy customers and well informed too!

 

[Joeybgood]

Looking forward to my Spring Level3 arriving in a couple weeks or so. Very excited about this DAC. Reallly hoping it will be my end-game. Thank you so much @bimmer100 for your invaluable assistance and for answering all my questions. It's truly been a pleasure doing business with you Tim. 

 

[Pixelplay]

  Looking forward to my Spring Level3 arriving in a couple weeks or so. Very excited about this DAC. Reallly hoping it will be my end-game. Thank you so much @bimmer100 for your invaluable assistance and for answering all my questions. It's truly been a pleasure doing business with you Tim. 

I took delivery of mine (level 3) yesterday and it is warming up/burning in as I am typing this....
I just wanted to take the time to second Joeybgood's experience dealing with Tim at Kitsune, I too took a punt on the new unreviewed Holo Spring 3 dac and to say that I am over the moon in this early stage is an understatement! There will be more to follow.
 
Thank you again Tim
 
To people thinking about purchasing new equipment, give the little guys a go. Often they take the punt and front up their hard earned $ to bring unheard of brands to the wider audience with much smaller markups. Do your due diligence and in most cases you will be rewarded.

 

[bimmer100]

for those questioning the balanced. Jeff wanted to show the renderings of the design..the top and bottom show the full resistor network for each.
 
here is a copied email from him
 
"
I think these two pictures can explain the true balance very well. The bottom side has the same resistor ladders as top side.
 
XLR is using all of the circuit and RCA is just using half of them. The balanced output has the better performance(THD, noise) and also better common mode rejection rate. If your listening environment contains interference, either from AC power or from air. Then you will find a full balanced system can really help a lot.
Best Regards
Jeff Zhu
"
 

 

[greenkiwi]

Excellent!
 
I think that has tipped my hand.

 

[greenkiwi]

I'd been wondering since you could only see what looked like one pair of resistor networks on the top.