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Review and Measurements of Holo Audio Spring DAC

WolfX-700

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#1
This is a detailed measurement and review of the Holo Audio Spring DAC.I borrowed this unit from a friend who owns this product.I have an instinctive aversion to the discrete R2R DAC products.Usually they will have very bad measurements. For example, high harmonic distortion, ugly IMD and Multitone results.

But there are exceptions, and this is one of them. The measurement results of the Holo Audio Spring DAC are quite acceptable!


Photo.jpg





I think this is a big and heavy unit. The case is made of 5 mm thick aluminum alloy - I think it is 6061 from the touch.

I like the white dot matrix LED display. However, the color matching of the buttons and side panels should still be reconsidered.Because their colors are too bright and too light. It has an adverse effect on the overall texture. Make the entire seemingly serious unit frivolous.

The button doesn't feel good enough either. Pressed sounds and feedback are not enough to match the price.

The USB and I2S inputs accept PCM data up to 32/768 and DSD512, the S/PDIF inputs up to 24/192 and DSD64. The outputs are balanced (XLR) and single-ended (RCA).



However, let's take a look at the measurement results of this discrete R2R DAC.

ALL.jpg


I got a 4V output at -2dbFS. Distortion/SINAD performance is amazing for discrete R2R DACs!

The following are high-order FFTs for observing noise, such as power supply noise. Most of the spike except the harmonics are lower than -140dbrA. Great performance!

FFT.jpg



Dynamic-Range---AES17.jpg




Let's look at intermodulation distortion versus level.

SMPTE-Ratio.jpg

I think this is the average.


The J-Test:
J-TestDAC.jpg



Linearity:
Linearity-(-20.jpg




Multitone:
Multitone.jpg




THD+N The distortion of the high frequency part is slightly worse. In the measurement, I chose the bandwidth of 90K and 24K respectively.

THD+N-Ratio-FREQ.jpg



Here are three different OS settings:

Please forget the label on the right. Yellow is NOS, blue is OS, red is OS DSD.

NOSOS.jpg
 
Last edited:

bunkbail

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#3
Is the DAC operate on OS mode? Couldn't imagine it measures that good on NOS mode.
 

bunkbail

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#5
Wow. Must be a half-assed OS implementation then. Wonder how it would measure with HQPlayer's upsampling at DSD512/DSD1024 sample rate.
 

pkane

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#7
This is a detailed measurement and review of the Holo Audio Spring DAC.I borrowed this unit from a friend who owns this product.I have an instinctive aversion to the discrete R2R DAC products.Usually they will have very bad measurements. For example, high harmonic distortion, ugly IMD and Multitone results.

But there are exceptions, and this is one of them. The measurement results of the Holo Audio Spring DAC are quite acceptable!


View attachment 39904




I think this is a big and heavy unit. The case is made of 5 mm thick aluminum alloy - I think it is 6061 from the touch.

I like the white dot matrix LED display. However, the color matching of the buttons and side panels should still be reconsidered.Because their colors are too bright and too light. It has an adverse effect on the overall texture. Make the entire seemingly serious unit frivolous.

The button doesn't feel good enough either. Pressed sounds and feedback are not enough to match the price.

The USB and I2S inputs accept PCM data up to 32/768 and DSD512, the S/PDIF inputs up to 24/192 and DSD64. The outputs are balanced (XLR) and single-ended (RCA).



However, let's take a look at the measurement results of this discrete R2R DAC.

View attachment 39905

I got a 4V output at -2dbFS. Distortion/SINAD performance is amazing for discrete R2R DACs!

The following are high-order FFTs for observing noise, such as power supply noise. Most of the harmonics except the harmonics are lower than -140dbrA. Great performance!

View attachment 39906


View attachment 39895



Let's look at intermodulation distortion versus level.

View attachment 39896
I think this is the average.


The J-Test:
View attachment 39912


Linearity:
View attachment 39909



Multitone:
View attachment 39910 THD+N The distortion of the high frequency part is slightly worse. In the measurement, I chose the bandwidth of 90K and 24K respectively.

View attachment 39901
This is a good result. Much better than measured by Stereophile with the same DAC and a few dB better than what I measured with mine (SINAD). In my tests J-test improves with OS mode, and is almost completely clean when fed a high-rate DSD signal. Glad you were able to confirm that this is an exceptional discrete R2R DAC!
 

maxxevv

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#8
Great measuring R2R DAC ! That's something implemented well and right there !!!

OT: I can assure you, you can't tell what grade of aluminium that is purely by touch / feel. Surface finishing alone will change that tactile feedback completely. I deal with machined parts most regularly in my work.

But chances are good that its indeed 6061. Its the most commonly used machining aluminium. Mostly because its easily available and because of that, relatively cheaper than some other grades. And machine shops love them because they are relatively easy to handle.
 

WolfX-700

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#9
Great measuring R2R DAC ! That's something implemented well and right there !!!

OT: I can assure you, you can't tell what grade of aluminium that is purely by touch / feel. Surface finishing alone will change that tactile feedback completely. I deal with machined parts most regularly in my work.

But chances are good that its indeed 6061. Its the most commonly used machining aluminium. Mostly because its easily available and because of that, relatively cheaper than some other grades. And machine shops love them because they are relatively easy to handle.

In fact, I think it is 6061 because its outer casing has a good texture. This is not like dealing with some cheap devices (most devices seem to use the 2000 series). These units have a rough surface and lack hardness and fineness.

But I don't think it will use the 7000 series, because the overall manufacturing cost of that is too high.
 

maxxevv

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#10
In fact, I think it is 6061 because its outer casing has a good texture. This is not like dealing with some cheap devices (most devices seem to use the 2000 series). These units have a rough surface and lack hardness and fineness.

But I don't think it will use the 7000 series, because the overall manufacturing cost of that is too high.
Texture can be easily created. Its just an additional process.

Scotbrite scrubbing, Sandblasting ( different sand particle sizes and blasting pressures will alter the result too), anodizing with/ without Teflon embedding, Bead blasting, EN Plating all will produce different texture results.

Most of the time, its because the cheap devices use the cheapest processes to finish off the surface, hence the all feel the same that way.

Hardness part can be altered too with hard anodizing. Most of the time, cheap devices use high cutting rates, that result in less than stellar finishes, edges.

Most machine shops don't like to deal with 7000 series for high volume production. It requires fresh cutters, and machines set at higher spindle rates and slower cutting speeds. That is over an above their baseline material costs being higher too. Hence, their overall higher costs.
 

WolfX-700

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#11
Wow. Must be a half-assed OS implementation then. Wonder how it would measure with HQPlayer's upsampling at DSD512/DSD1024 sample rate.
I just tested Roon's upsampling to 256DSD measurements (my Roon Server is not powerful enough to do 512 and I don't have HQ).

DSD2.jpg



It looks like there is a issue with its USB module. The clock is too fast.
 

majingotan

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#12
Finally a decently measuring R2R DAC, discreet ladder resistors to boot! IMO I would probably recommend this if you want a fancy way of reproducing digital audio without compromising 16 bit audio performance at the minimum at all.
 

Veri

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#13
This is a detailed measurement and review of the Holo Audio Spring DAC.I borrowed this unit from a friend who owns this product.I have an instinctive aversion to the discrete R2R DAC products.Usually they will have very bad measurements. For example, high harmonic distortion, ugly IMD and Multitone results.

But there are exceptions, and this is one of them. The measurement results of the Holo Audio Spring DAC are quite acceptable!


View attachment 39904




I think this is a big and heavy unit. The case is made of 5 mm thick aluminum alloy - I think it is 6061 from the touch.

I like the white dot matrix LED display. However, the color matching of the buttons and side panels should still be reconsidered.Because their colors are too bright and too light. It has an adverse effect on the overall texture. Make the entire seemingly serious unit frivolous.

The button doesn't feel good enough either. Pressed sounds and feedback are not enough to match the price.

The USB and I2S inputs accept PCM data up to 32/768 and DSD512, the S/PDIF inputs up to 24/192 and DSD64. The outputs are balanced (XLR) and single-ended (RCA).



However, let's take a look at the measurement results of this discrete R2R DAC.

View attachment 39905

I got a 4V output at -2dbFS. Distortion/SINAD performance is amazing for discrete R2R DACs!

The following are high-order FFTs for observing noise, such as power supply noise. Most of the harmonics except the harmonics are lower than -140dbrA. Great performance!

View attachment 39906


View attachment 39895



Let's look at intermodulation distortion versus level.

View attachment 39896
I think this is the average.


The J-Test:
View attachment 39912


Linearity:
View attachment 39909



Multitone:
View attachment 39910



THD+N The distortion of the high frequency part is slightly worse. In the measurement, I chose the bandwidth of 90K and 24K respectively.

View attachment 39901


Here are three different OS settings:

View attachment 39922
Great post!! Some typo maybe:
-Most of the harmonics except the harmonics, do you mean most of the distortion except the harmonics is under -140dbrA?

-About the filters the colors don't match. Yellow is NOS, blue is OS, red is OS DSD.
 
Last edited:

Veri

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#14

WolfX-700

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#15
Great post!! Some typo maybe:
-Most of the harmonics except the harmonics, do you mean most of the distortion except the harmonics is under -140dbrA?

-About the filters the colors don't match. Yellow is NOS, blue is OS, red is OS DSD.

@amir anyone sending you this device? If no, possibly eligible for promotion to front page? :)
Thank you for your correction. I have edited it.
 
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