Review and Measurements of Holo Audio May --- Probably the best discrete R2R DAC

[majingotan]

I'm interested in the name and model

Discrete means it is NOT a DAC chip unlike some other R2R DACs out there that use a DAC chip

 

[WolfX-700]

Excellent! Now only if you could reach out and get a Denafrips Terminator to measure it would be awesome.

I found some Denafrips Terminator's not very authoritative measurement. I don't think it is comparable to May.

Of course I can measure it if I have a chance. I will make a more careful comparison.

and：

AP test chart from this website：https://6moons.com/audioreviews2/denafrips/1.html

I did a similar test and adjusted the scale to be basically the same：

May is the red line

 

[Rusty Shackleford]

Great job, @WolfX-700. Does the May have the same high-end rolloff in NOS mode as the Spring?

 

[WolfX-700]

Great job, @WolfX-700. Does the May have the same high-end rolloff in NOS mode as the Spring?

yes

 

[WolfX-700]

Suggestion: photos should show the full device (end to end) and also rear panels. Thanks!

After I have completed a series of measurements, I take pictures. I have even obtained permission to open the case to take pictures.

 

[raif71]

After I have completed a series of measurements, I take pictures. I have even obtained permission to open the case to take pictures.

Have you listened to the Holo Audio May? Surely you don't need permission to do that . I'm sure we'd like to read what you have to say about the sound.

 

[WolfX-700]

Have you listened to the Holo Audio May? Surely you don't need permission to do that . I'm sure we'd like to read what you have to say about the sound.

After making a measurement that excites me. I think letting me evaluate its sound will only lead to unbelievable results.

 

[WolfX-700]

Also it's better to show multitone with down sloping spectrum(pink for example) and NID(No Interharmonic Distortion). Also at different amplitude and/or with different numbers of sines.

 

[Pluto]

If I understand, PLL is a setting that rejects jitter? What is it exactly...

A PLL is the means by which the DAC locks to the incoming clock rate of AES, SPDIF and similar streams. Most probably, the PLL control on the unit adjusts the damping within the loop. In general, the more heavily damped the loop, the more immune it will be to incoming jitter with the quid pro quo that it is less able to "track" rapid variations of clock rate within the incoming data stream. Hence, a highly damped PLL circuit will tend to require a very stable incoming signal. This is typically why poorer quality digital outputs (typically on TVs) suffer more dropout problems.

The operation of a heavily damped PLL is entirely analogous to the idea of a heavy flywheel having more inertia and thus being less prone to momentary speed variations. For the same reasons, the setting with high damping may well take noticeably longer to lock up to an incoming stream than lesser damping settings (it takes longer to get a heavy flywheel up to speed).

It is worth saying here that all such PLL issues are redundant when using an asynchronous USB input for the simple reason that the DAC clock is derived directly from its internal oscillator and the speed of the incoming data is regulated to match the long term requirements of that internal clock, short term requirements being handled by an internal buffer i.e. a bucket with a hole in the bottom that will be maintained at approximately half full.

 

[gvl]

Clearly heroic efforts are required to engineer and manufacture such a device, hence the price.

 

[chashaodan]

View attachment 40850

狼总，能麻烦测一下1khz方波吗？

 

[WolfX-700]

狼总，能麻烦测一下1khz方波吗？

今晚是拆机时间…… 方波得晚点了

 

[Veri]

What R2R DAC does it use?

I'm interested in the name and model

I'm confused by your questions. It's an R2R DAC made from the ground up, sign maltitude ladders with FPGA error correction. There's no PCM63/TDA1543/AD CRUZ/DSD1793 or other multibit or hybrid multibit chip used, it's a custom boutique design.

Really crazy to see it reach 118dB SINAD. Compare to Soekris, Airist, Denafrips, Audio-Gd(laughable performance). It's state of the art but yeah, $4000...

 

[WolfX-700]

狼总，能麻烦测一下1khz方波吗？

 

[pwjazz]

This seems really interesting from an engineering heroics perspective, but from The developer's perspective, is there any supposed benefit to a discrete R2R design versus just doing a cheap Delta sigma chip based solution? Honest question.

 

[pkane]

This seems really interesting from an engineering heroics perspective, but from The developer's perspective, is there any supposed benefit to a discrete R2R design versus just doing a cheap Delta sigma chip based solution? Honest question.

Probably not. R2R is a conceptually simple, brute-force way to do D2A conversion that turns out to be tricky to implement well. At one time I was enamored with R2R idea, and still own a recent Holo Spring L1, but can't say that it's any better than a decent D-S DAC at 1/4 the price.

 

[WolfX-700]

This seems really interesting from an engineering heroics perspective, but from The developer's perspective, is there any supposed benefit to a discrete R2R design versus just doing a cheap Delta sigma chip based solution? Honest question.

I am also considering whether to buy this unit. There is a good reason for me to consider paying: it looks so pretty inside.

It's a look that will fascinate people like me.

 

[WolfX-700]

Suggestion: photos should show the full device (end to end) and also rear panels. Thanks!

 

[garbulky]

I'm confused by your questions. It's an R2R DAC made from the ground up, sign maltitude ladders with FPGA error correction. There's no PCM63/TDA1543/AD CRUZ/DSD1793 or other multibit or hybrid multibit chip used, it's a custom boutique design.

Really crazy to see it reach 116dB SINAD. Compare to Soekris, Airist, Denafrips, Audio-Gd(laughable performance). It's state of the art but yeah, $4000...

How did they get resources to create their own r2r dac chip/fpga chip?! I don’t understand.

 

[WolfX-700]

How did they get resources to create their own r2r dac chip?! I don’t understand.

https://www.tek.com/blog/tutorial-digital-analog-conversion-r-2r-dac