KTE Spring2 technical measurements

Holo Audio KTE Spring2 technical measurements

Standard Prologue
If you are unfamiliar with audio measurements please use a search engine with the query:
"audio measurements" or "audio measurement handbook"
Look for publications by Richard C. Cabot and also by Bob Metzler, both from Audio Precision. There are other useful publications as well. These will provide basic knowledge.
Interpretation of the following measurements is beyond the scope of technical measurements posts.

The data presented were collected as follows:

1. PrismSound dScope III, picoscope 5243B, Cal Test CT2593-2 balanced probe
2. Tecnec 75R spdif cable
3. Balanced XLR cables Belden 1800F with Neutrik 110R AES connectors
4. Single Ended cables Mogami 2964 1 meter with Amphenol RCA connectors
5. 100 Kohm load used for measurements
6. dScope analyzer sample rate 48 KHz unless otherwise noted
7. DAC 44.1 KHz sample rate, 24 bit depth unless otherwise noted
9. Audioquest Forest and Schiit Pyst USB cables
9. Vaunix Lab Brick USB hub
10. Shielded 14AWG and 16AWG power cables
11. NOS filter mode unless otherwise noted

Measurements are made in accordance with AES17:2015

Holo Audio KTE Spring2
Measurements for record commenced after warmup of at least 168 hours.
Measurements were performed over a period of several days.
Balanced measurements were performed twice, one month apart for consistency verification.

Index
Post 1 - measurement setup description, highlights
Post 2 - spdif input - Bal XLR outputs part A
Post 3 - spdif input - SE RCA outputs part B
Post 4 - USB ASIO input - Bal XLR outputs part C
Post 5 - USB ASIO input - SE RCA outputs part D
Post 6 - Filter response
Post 7 - reserved for additional data and corrections
Post 8 - reserved

Notable highlights:
While the KTE May is Holo Audio's statement DAC, KTE Spring2 is very close and even exceeds KTE May performance in residual noise spectrum.
Ultra low distortion
Power supply noise spectrum are at or below -160 dBFS in balanced output
The power supply spectrum residual noise was so low it was necessary to reconfigure y-axis scale low enough to see the noise floor.
Balanced output Dynamic Range of 135 dB
Balanced output Cross-talk is dual mono with > 145 dB isolation
Balanced output Gain Linearity is nearly perfect to -110 dBFS, less than +/- 2 dB to -130 dBFS
Exceptionally low jitter
NOS square wave is near perfect with fast slew rate and, of course, no filter ringing
Single Ended performance is somewhat less than Balanced output, as is typical
Single Ended performance is still exceptional compared to other DAC SE outputs

Well done Jeff Zhu!

Commentary:
Power supply is at least 50% of any audio component's design. The higher the level of performance the more the power supply matters. Holo Audio recognizes this and has gone to heroic lengths enhancing KTE Spring2's power supply, keeping noise to 100s of nanovolt levels while supplying 10s of volts throughout the system. Make no mistake, this is an incredible achievement. Every aspect of performance has been scrutinized and optimized. The result is an equally impressive natural presentation, allowing one to observe amplifer character with ease. I have my pairing favorites, based on my personal preferences.

For more descriptive narration see @Torq's comment:

https://www.superbestaudiofriends.o...tsune-tuned-edition-impressions-reviews.3172/

The Spring Level 3 has much in common with the KTE Spring2 where the latter is the former performance enhanced.

Measurement setup picture example:


Listening pictures
Way more than usual listening session hours disappeared while evaluating KTE Spring2 with a variety of headphone amps. KTE Spring2 has received 400+ listening hours. I have enjoyed this DAC so much as to buy one for myself. Here are a few of my favorites DAC - Headamp combinations:

 

spdif input Bal output measurements part A

KTE Spring2 Dynamic Range spdif input Bal output

Excellent performance, as is most of the following data presented

Dynamic range, in simplified terms
1. find maximum output voltage at 0 dBFS
2. find residual noise with a -60 dBFS 1 KHz stimulus, removed from analysis by window notch
3. Dynamic Range is the difference between maximum output and residual noise
Specifics are in AES17 section 9.3 (measurebators do your homework please)
Example here:
https://www.maximintegrated.com/en/design/blog/spec-dynamic-range.html

Why we have a -60 dBFS stimulus
Some clever codec designers include an output gate that shuts off when there is no signal present. This has the dual benefit of lowering output idle noise while also gaming the measurements. AES became wise requiring a -60 dBFS stimulus so any such gates are open during measurement and true Dynamic Range performance measured.

KTE Spring2 -120dBFS sine spdif input Bal output

Wow! -120 dBFS sine representation on an R2R design. Impressive.

KTE Spring2 A04 THD+N THD nth-HD FFT spdif input Bal output


KTE Spring2 50 + 7000 Hz spdif input Bal output - Left Channel


KTE Spring2 Gain Linearity spdif input Bal output - Left Channel


KTE Spring2 THD+N vs Frequency spdif input Bal output - Left Channel


KTE Spring2 Residual Noise Bal spdif input Bal output - Left Channel

Note the y-axis extends down to -180 dBFS rather than the usual -160 dBFS!!!
KTE Spring2 DAC residual noise is the lowest I've ever measured and exceptional considering R2R design.

Complete spdif input Bal output analysis report pdf attached

 

spdif input SE output measurements part B

KTE Spring2 A04 THD+N THD nth-HD FFT spdif input SE output


KTE Spring2 50 + 7000 Hz spdif input SE output - Left Channel


KTE Spring2 Gain Linearity spdif input SE output - Left Channel


KTE Spring2 THD+N vs Frequency spdif input SE output - Left Channel


KTE Spring2 Residual Noise spdif input SE output - Left Channel


Complete spdif input SE output analysis report pdf attached

 

USB ASIO input Bal output measurements part C

KTE Spring2 Dynamic Range USB input Bal output


KTE Spring2 -120dBFS sine USB input Bal output


KTE Spring2 A04 THD+N THD nth-HD FFT USB input Bal output


KTE Spring2 50 + 7000 Hz USB input Bal output - Left Channel


KTE Spring2 Gain Linearity USB input Bal output - Left Channel


KTE Spring2 THD+N vs Frequency USB input Bal output - Left Channel


KTE Spring2 Residual Noise Bal USB input Bal output - Left Channel


Complete USB input Bal output analysis report pdf attached

 

USB ASIO input SE output measurements part D

KTE Spring2 A04 THD+N THD nth-HD FFT USB input SE output


KTE Spring2 50 + 7000 Hz USB input SE output - Left Channel


KTE Spring2 Gain Linearity USB input SE output - Left Channel


KTE Spring2 THD+N vs Frequency USB input SE output - Left Channel


KTE Spring2 Residual Noise USB input SE output - Left Channel


Complete USB input SE output analysis report pdf attached

 

Filter Response

Measurement conditions
1. -4 dBFS 20Hz square wave
2. 44.1 KHz sample rate
3. USB ASIO input
4. SE output to oscilloscope

Filter response measured the same across inputs and outputs

KTE Spring2 10mS/div NOS


KTE Spring2 10mS/div OS


KTE Spring2 10mS/div OS PCM


KTE Spring2 10mS/div OS DSD


KTE Spring2 200uS/div NOS


KTE Spring2 200uS/div OS


KTE Spring2 200uS/div OS PCM


KTE Spring2 200uS/div OS DSD


KTE Spring2 200uS/div NOS BW calculation

Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
Where RT = 10 to 90% Rise Time
0.35 / 9.251 uS = 37.8 KHz

KTE Spring2 200uS/div OS BW calculation

Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
Where RT = 10 to 90% Rise Time
0.35 / 33.66 uS = 10.4 KHz

 

reserved for additional data and corrections

Additional AES input Bal output measurement report attached.

 

reserved.

 

Thanks for the update! It's interesting to see this dac kept being stabilized for another additional weeks.

I am kinda curious why this dac failed to get a dedicated subjective thread unlike spring 1. The thing I haven't heard much about this dac in sbaf led me to overlook.. but the audition was highly eye-popping experience. Imho this (and probably also May) should be shortlisted for those who want cost no object zero compromise (well.. to some extent lol) dacs.

 

^ FWIW, I tried reaching out to them recently to try a DAC and it seems like they're a bit short on supply right now. I too am trying to find a May to try.

 

As near as I can tell they have 3 different dac's, at least one of which is on a its second version (i.e. "V2"), and each of the three dacs has three different "levels". I have read reviews where the person either admitted they were not clear as to which dac they actually had, or thought they knew at first and then was later corrected by someone else. Holo Audio shoots themselves in the foot with this 'video game level' marketing/product statergery IMO as it has a carney like feel to me.

 

I've got a Holo May KTE on loan right now. I don't have enough listening time other than to say that it's excellent. It's a touch dark next to my Gungnir Multibit but no less detailed. It also separates layers more cleanly and does bass better, quality-wise but also perhaps a touch more quantity.

I probably won't end up keeping it--it's too spendy for me--but it's been a really interesting audition. And, of course, I'm wondering how close the Spring KTE would get me to the May.

 

Quote from @atomicbob 's 1st post on this thread:

While the KTE May is Holo Audio's statement DAC, KTE Spring2 is very close and even exceeds KTE May performance in residual noise spectrum.​

I had owned the original Holo Spring (level 3 KTE) and Spring 2 KTE is on a distinctly higher plane: still tonally dense, but more spacious, detailed, layered. I bought it unheard based on blending my experience of the older Spring with @atomicbob's analysis and a few exchanges with other SBAFers. Not planning on trying other DACs anytime soon, this is very satisfying. I leave it on all the time, plugged into a solid Furman power protector & conditioner.

 

Yes, the KTE Spring 2's performance in residual noise also caught my eye.

The measurements being close is pretty impressive, but I'm equally curious if anyone's has listening impressions on both. A longshot, perhaps....

 

I don't know what in the measurements explains my impressions, but of all the NOS DACs I've owned (Spring 1 KTE, Metrum Onyx, Sonnet Morpheus, Spring 2 KTE), Spring 2 KTE is closest to squaring the circle with superior tonal density while avoiding the sluggish dynamics or smeariness that the others exhibit in different mixes. For the music I listen to on headphones, mostly modern jazz and small-ensemble classical, with the amps and headphones I own, this is the best DAC I've owned (also compared with OS Soekris dac1541 and Schiit Yggdrasil A2).

 

Yeah, measurements alone would suggest (I think) that my Matrix X-Sabre Pro should sound very much like the Holo May. And yet the Holo May has a distinctly different signature and way with detail.

This is obvious, perhaps, but still fascinating. I'll try to post more detailed impressions of the Holo May soon.

 

Would you mind sharing how you made this happen? If it needs to go via PM, that's fine, but I suspect I'm not the only person here who would like to hear the May or Spring 2.

BTW, has anyone heard the Spring2 back to back with the May?

 

I reached out about a Spring 2 a couple weeks ago and haven't heard a peep out of them. I should probably try again...

They've been showing out of stock on the spring since early/mid Jan (they did have a single Lvl 1 available, but it's long gone)
-----edit------
I'd love to hear comparisons of the different levels... but it seems like it fall into 2 camps. Either "I got the KTE because the premium didn't bother me" and "The KTE is snake oil". But I can't say that I remember reading about anyone that has heard multiple versions.

 

A dealer I've worked with a lot got one in used.

Yeah, they seem hard to come by from the source right now. I remember having prompt communications with Tim in the past however.

 

I thought all the holo audio stuff are made to order, atleast in the USA. Don't believe Tim stocks anything.