HOLO Audio Spring DAC - R2R DSD512

[Miska]

3 hours ago, bodiebill said:

I am using the balanced XLR's out from my Spring 3 L2. Is it a good idea to use shorting RCA plugs/caps on the unused RCA outputs?

 

The reason I ask is that I just tried these, that I borrowed these from a friend

https://www.akikoaudio.com/en/akiko-audio/akiko-audio-audio-accessories/56-qwd

and they do seem to make a positive difference. But I wonder whether shorting plugs could have a similar effect, provided they do no harm.

 

Such make only sense for inputs. Not for outputs. For outputs it just increases power draw significantly and in worst case could damage the device.

 

[Miska]

24 minutes ago, SwissBear said:

What surprized me too was the lack of additonal power shown when feeding this DAC with DSD 256/512 over NAA. As if the simple setup of the Mac Mini connected via USB to the Holo Spring 3 was able to squeeze the very best out of this DAC.
Is this in accordance with your own measurements ? Have I missed anything in my process ?

 

Yes, the Holo has good isolation, so the USB is trouble free. In particular when you use with a proper USB3 cable (with the big blue type-B connector). But also fine with regular USB2 cable if you don't have USB3 source.

 

NAA is still useful when you want small fanless endpoint and locate the HQPlayer server in a different room, which is the case for me. So I have the UP Gateway running as a NAA, hidden behind Spring 3. While big HQPlayer server with relatively loud fans is running in corner of my office. So the loud fans on the server won't disturb listening...

 

But yes, Mac Mini, standalone, can run it at very high performance. If you want to try DSD512 or such, you need more power though. And macOS + DoP is limiting your output rate to DSD256. This is also where Linux-based NAA becomes handy.

 

[Miska]

3 hours ago, SwissBear said:

One other thing I noticed in my measurements, and which I would like to understand more when you have time to comment, is that distorsion produced by the Holo Spring 3 seems to be a monotonic function of upsampling resolution (see attached).

 

I don't get as drastic differences (with ASDM7ECv2):

 

 

3 hours ago, SwissBear said:

In this context, how do you evaluate the best compromise between a potential decrease of quantisation noise, which would be brought by higher resolution, and the increase of distorsion which is measurable ?

 

It is up to balancing. Level of ultrasonic noise drop compared to distortion increase is something like every doubling of sampling rate increases distortion some 3 - 6 dB and ultrasonic noise moves to twice higher frequency and drops some 20 dB. If you use for example class-D amplifier, you may want to focus on reducing ultrasonic noise levels. At DSD512 the ultrasonic noise level drops below analog noise floor.

 

3 hours ago, SwissBear said:

Also, have you found, in the course of your measurements, DAC technologies which behave better in the field of distorsion when using high sampling frequencies like DSD512 ? Are T+A 200 or Teac 701n any better at this ?

 

Distortion increase and noise drop ratio is similar. Most typical case is that usually DSD256 gives best balance and flat noise floor for 100+ kHz wide band which is good for any hires music content. With ultrasonic noise levels at similar level as inherent in-band noise floor of 16-bit content.

 

[Miska]

1 hour ago, SwissBear said:

Thank you . I was comparing DSD64 to DSD512.

 

Your DSD512 results are just worse than what I've got. Which modulator did you use?

 

[Miska]

On 8/27/2023 at 8:14 PM, SwissBear said:

ASDM7EC-Super

 

Here's what I've got today with DSD512 and ASDM7EC-super:

 

I would use DSD256 in your case, as it fits all PCM hires available today. But up to you of course!

 

[Miska]

43 minutes ago, SwissBear said:

Can I ask the level of HQPe output you are using when making your measurements?

 

Same as listening volume so -3 dBFS. Source files in most cases are 0 dBFS 32-bit TPDF dithered 44.1k PCM (for some tests like TIM, higher rates are needed though). So the source files are always the same and will never cause inter-sample overs, no matter what I'm measuring, PCM or DSD.

 

Before poly-sinc-gauss group I used poly-sinc-ext2. But now either poly-sinc-gauss-long or poly-sinc-gauss-xl.

 

All my three Spring's are L2 versions. And audio band measurements are done from balanced outputs. In above case over 5m long "microphone" XLR cable, since I didn't want to move the devices... But usually I use 1.5m long XLR cable. Wide band measurements (5+ MHz) are done from single-ended outputs using RG58 coaxial cable.

 

[Miska]

45 minutes ago, Escarbille said:

If I understood your message correctly, with a class D it is better to increase the output rate as much as possible, is that right?

 

Depending on DAC. For example with Holo Audio you are certainly fine already at DSD512. But with Holo and class-D I would possibly consider going for DSD512 instead of DSD256. Of course you could still go further to DSD1024, but you don't win as much anymore.

 

While if you have for example Benchmark AHB2, one could still consider using DSD256 instead of DSD512...

 

So it depends, also on things like whether you use HQPlayer's volume control and go direct to power amp or such.

 

Listening with headphone system is also different than listening with loudspeaker system. And for example listening with IEM's in airplane is different than listening with open backs at home, etc.

 

So this is about balancing different properties for one's system and ears. I think it is worth considering different use cases, and for example use different settings for different cases.

 

[Miska]

DACs do sound different, despite similar SINAD numbers. For example Holo and T+A do sound different, while both perform extremely well in terms of SINAD figures.

 

Differences in conversion stage and analog filter/buffer stage implementations do make a difference. And those differences are more complex than what a simple SINAD figure can express.

 

[Miska]

27 minutes ago, dericchan1 said:

@Miska

my class d amp, Nuprime Evolution STA, stated that 

• 650KHz high-speed switching frequency allows greater resolution to be achieved.

If switching takes place at 650khz, is there still a benefit of setting output to dsd512 vs dsd256? 

 

Yes, certainly. Those switching rates are rather low compared to DSD switching rates...

 

[Miska]

7 minutes ago, SwissBear said:

Do you expect the Holo Cyan to sound differently from Holo Spring and Holo May, knowing that they share the same lineage, and that they display similar SINAD according to the sellers' claims ?

 

Not necessarily much, depending on different the analog stages are. But the D/A stage at least is somewhat different.

 

Also Spring 2 and Spring 3 behave somewhat different way, so those two may also sound somewhat different. Although I have not noticed any major differences in sound.