Holo Audio Spring R2R DAC
Dec 10, 2016 at 11:49 AM Post #526 of 3,005

lukeap69

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Dec 10, 2016 at 2:07 PM Post #528 of 3,005

lukeap69

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Thank you, one more question what about the digit display size, can you make the numbers smaller in the display window ?


Not the I know of. Holo made sure the display can be read from 1km away. :grinning:
 
Dec 10, 2016 at 3:35 PM Post #530 of 3,005

rajacat

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I agree with that, though are wondering about  the R2R ladder instead.
The R2R ladder, which is at the heart of this DAC, is just a bunch of resistors, with very tight resistance values.
The value of resistance changes with temperature, which means that if you heat that resistor array unevenly, you may get resistors that increase their resistance more than others. Some calculations would be required to check when this becomes significant. Some designers (e.g. Soekris) offer their R2R designs choosing resistors with very tight tolerance. for what I have read, other designers like Jeff (Holo Audio) do not rely so much in the tolerance of each individual resistor, but take more in account other factors, such as the effect (on resistance) of connections/solderings, which may be of more effect than choosing the resistors with the tighter tolerance. I also suspect myself than (uneven) heating of the R2R array (or/and taking in account the resistance of solderings and conductors)  can become more important than going for the most expensive resistors.

Perhaps this is where "linear compensation" comes into play. The additional R2R ladder will compensate for small changes in the resistors' value caused by heat or less than optimum tolerances.
 
"There’s an additional R2R ladder in the Spring DAC, it 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. 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."
 
quote from Kitsune website
 
Dec 11, 2016 at 2:43 AM Post #532 of 3,005

guymrob

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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.

 


​I've some questions after I've auditioned Holo Spring DAC
 
In NOS mode: How do the DAC takes care of the noise central around 44.1kHz sampling frequency? If I understand correctly, over-sampling(8x typical) is supposed to the shift the sampling noise to a higher band and make analogue/digital filtering less aggressive. If such noise is not filter out, it may get into power amps; this may cause instability and sometimes over-heating.
 
In OS mode, what is the over-sampling factor applied for PCM and DSD? 2x, 4x or 8x of its native sample?
 
Conversion mode: OS PCM mode means works like OS mode for PCM but DSD is converted to PCM on the fly?
                              OS DSD mode means works like OS mode for DSD but PCM is converted to DSD on the fly?
 
Thank you for your quick reply
 
Dec 11, 2016 at 9:35 AM Post #533 of 3,005

WNBC

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Spring DAC KTE arrived this week.  Thanks to Tim at Kitsune.  Arrived exactly in the timeframe promised, luckily I got in on the batch before the big holiday rush.  DAC has been running for less than 12 hours and I must say that I'm quite impressed.  From what I understand, the sound is going to mature even more during break-in, but from just what I am hearing now, it's a keeper.  Too soon to be analytical, but one knows when he or she hears something special and this is it for me.  Plenty of detail and a dynamic, natural presentation.  It will take time to dissect it with any justice, but I know I like it :)  For now, it is computer to Intona to SU-1 to I2S of Spring.   
 
Pics for fun....
 

 

 
Dec 11, 2016 at 10:15 AM Post #534 of 3,005

comzee

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  For now, it is computer to Intona to SU-1 to I2S of Spring.   
 

I see that Pioneer v7200 , I have one too 
beerchug.gif

 
Also, I owned Intona and still own SU-1. I think the SU-1 is a fantastic product. From my own A/B and personal opinion of testing, I don't think the Intona does anything. When I used it with my SU-1 I didn't hear a difference, maybe even slightly worse... ymmv.
 
+1 for the Elear. Does that compliment the HD800 well?
 
Dec 11, 2016 at 10:30 AM Post #535 of 3,005

WNBC

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I have been lazy about CD transports and just keep on using the Pioneer when I want to get away from a computer source. 
 
With the Gumby and now Spring, I've always had the Intona in play as it has been highly regarded by many.  I should get around to taking it out of the path to see whether there is a positive or negative effect.  There are several options out there, Intona is my first attempt at USB galvonic isolation.  Maybe others can chime in as well because I'm sure there are plenty of users of the Intona in this thread.  
 
Elear does in fact complement the HD800.  To me, the Elear is an intimate (relative small soundstage width), warm, transparent and detailed headphone.  I like its tone as well.  I am on the fence about keeping it.  It has its well-documented faults.  If it was a $500-600 headphone it would be a no brainer to keep.  At $1000 I feel obligated to love it.  I did in fact have it up for sale, but buyer didn't end up having enough funds and I haven't reposted it.  The Spring is making me re-think selling it as I like the pairing.  TH-900 might be the perfect complement to the HD800 though
wink.gif
.
  
 
 
Quote:
  I see that Pioneer v7200 , I have one too 
beerchug.gif

 
Also, I owned Intona and still own SU-1. I think the SU-1 is a fantastic product. From my own A/B and personal opinion of testing, I don't think the Intona does anything. When I used it with my SU-1 I didn't hear a difference, maybe even slightly worse... ymmv.
 
+1 for the Elear. Does that compliment the HD800 well?

 
Dec 11, 2016 at 7:21 PM Post #537 of 3,005

Energy

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There are several options out there, Intona is my first attempt at USB galvonic isolation.  Maybe others can chime in as well because I'm sure there are plenty of users of the Intona in this thread.  

 
Singxer SU-1 already offers galvanic isolation does it not?
 
Dec 11, 2016 at 7:53 PM Post #539 of 3,005

WNBC

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A suggestion was made to me try both in tandem. When everything is well burned in I can pull the Intona from the chain and hear whether there is a positive or negative effect. If not needed I can use it elsewhere or sell it.

Edit: looking over my past discussion about this topic, the level of isolation from the SU-1 is definitely not on the same level as the Intona and because I use a laptop as my source there could be some added benefit to having the Intona in play.  Desktop computers might not receive any extra benefit.  I knew this would be more of a slight tweak and maybe not noticeable at all depending on how much noise is coming from my Macbook USB port.  More of a small tweak item than necessity.  
 
Thanks for the reminder guys as I might have just left it in the chain indefinitely because I had forgotten the details behind the purchase.  I'll investigate this more when the DAC is at full potential. 
 
Dec 12, 2016 at 1:30 PM Post #540 of 3,005

Articnoise

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  A suggestion was made to me try both in tandem. When everything is well burned in I can pull the Intona from the chain and hear whether there is a positive or negative effect. If not needed I can use it elsewhere or sell it.

Edit: looking over my past discussion about this topic, the level of isolation from the SU-1 is definitely not on the same level as the Intona and because I use a laptop as my source there could be some added benefit to having the Intona in play.  Desktop computers might not receive any extra benefit.  I knew this would be more of a slight tweak and maybe not noticeable at all depending on how much noise is coming from my Macbook USB port.  More of a small tweak item than necessity.  
 
Thanks for the reminder guys as I might have just left it in the chain indefinitely because I had forgotten the details behind the purchase.  I'll investigate this more when the DAC is at full potential. 

 

If you already have one Intona it’s worth a try, just the way you have planned. Maybe it will have no effect, maybe big enough to keep. Digital noise are generally tricky things to deal with in a resolving system. Mains power is even harder to get right IME. 

 

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