Does a DAC's output change as it warms up?

[vortecjr]

I noticed yesterday while looking into something unrelated.

I have been discussing offline, with some colleges, the so-called "ESS hump" observed in some DACs through the Inter-modulation distortion vs level measurements. I was asked if my old and now retired Twisted Pear Audio - Buffalo DAC exhibited the "ESS hump" so I said I would test it. I set up the AP machine and then connected the DAC which was in storage in my garage.

 

I got this result on the first test with the DAC cold. Yikes...separation on the l/r channels, partial hump in the middle, and rise at the end. Notice the time stamp of 6:58 PM.  

 

After the test above I was distracted and I came back after a while and ran the test again. Yikes again...still some separation on the l/r channels, distinct hump in the middle, and no rise at the end. Notice the time stamp of 7:47 PM.

  

Again there was no attempt to study the issue and just reporting what I saw. Clearly, the output of this DAC had changed over time, this DAC appears to have the "ESS hump" and some l/r channel issues. Anyway back into the garage it goes.

 

FYI this DIY DAC was instrumental in testing support for high sample rate PCM and DSD back in the early days and is currently used to test LVDS i2s sources.

[pkane2001]

53 minutes ago, vortecjr said:

I noticed yesterday while looking into something unrelated.

I have been discussing offline, with some colleges, the so-called "ESS hump" observed in some DACs through the Inter-modulation distortion vs level measurements. I was asked if my old and now retired Twisted Pear Audio - Buffalo DAC exhibited the "ESS hump" so I said I would test it. I set up the AP machine and then connected the DAC which was in storage in my garage.

 

I got this result on the first test with the DAC cold. Yikes...separation on the l/r channels, partial hump in the middle, and rise at the end. Notice the time stamp of 6:58 PM.  

 

After the test above I was distracted and I came back after a while and ran the test again. Yikes again...still some separation on the l/r channels, distinct hump in the middle, and no rise at the end. Notice the time stamp of 7:47 PM.

  

Again there was no attempt to study the issue and just reporting what I saw. Clearly, the output of this DAC had changed over time, this DAC appears to have the "ESS hump" and some l/r channel issues. Anyway back into the garage it goes.

 

FYI this DIY DAC was instrumental in testing support for high sample rate PCM and DSD back in the early days and is currently used to test LVDS i2s sources.

 

https://audiophilestyle.com/forums/topic/58238-this-weird-trick-lowers-dac-distortion/

 

Oh, and re: ESS hump, there's a good thread on ASR by a DAC manufacturer on how they solved it:

 

https://www.audiosciencereview.com/forum/index.php?threads/how-to-fix-ess-hump-on-sgd1-and-la-qxd1.10502/

 

 

[vortecjr]

9 hours ago, pkane2001 said:

 

https://audiophilestyle.com/forums/topic/58238-this-weird-trick-lowers-dac-distortion/

 

Oh, and re: ESS hump, there's a good thread on ASR by a DAC manufacturer on how they solved it:

 

https://www.audiosciencereview.com/forum/index.php?threads/how-to-fix-ess-hump-on-sgd1-and-la-qxd1.10502/

 

 

You got to love mansr.

 

I read the post on the ESS hump and it was interesting. Even though I tested a DIY DAC I was actually looking for a software solution. 

[jabbr]

This really makes the point that it’s how the ESS is implemented that affects the sound, as Charles Hansen always said. 
 

Too often a part is marketed. My experience also testing some low cost DACs, often with ESS chips. I’ve never typically liked their sound. Same point for using a clock. It’s not the clock specs that matter, rather than how the clock interacts with the entire circuit. Those mundane details are important!

[vortecjr]

5 hours ago, jabbr said:

This really makes the point that it’s how the ESS is implemented that affects the sound, as Charles Hansen always said. 
 

Too often a part is marketed. My experience also testing some low cost DACs, often with ESS chips. I’ve never typically liked their sound. Same point for using a clock. It’s not the clock specs that matter, rather than how the clock interacts with the entire circuit. Those mundane details are important!

Yes agree. I wonder if designers are just using a known reference design.  

 

Well aren't better spec'd clocks implemented better. I want to add the clock's power supply also matters. I'm curious if the changes made to fix the hump caused some other issue.       

[jabbr]

2 hours ago, vortecjr said:

 

Well aren't better spec'd clocks implemented better. I want to add the clock's power supply also matters.

 

The clocks power supply absolutely matters and when a clock manufacturer publishes phase noise plots, assume they are using a great PSU. Plopping in any old PSU ain’t gonna give you those specs. 
 

Great clocks are a commodity these days so we’d expect that a very well made DAC will use a very good clock. I’m saying that you can’t take a very cheap DAC and fix its layout problems by plugging in an uber expensive external clock. Layout issues with correlated jitter can’t be fixed by reducing random jitter. 
Sounds like a great story though. 

[alfe]

16 hours ago, jabbr said:

Great clocks are a commodity these days so we’d expect that a very well made DAC will use a very good clock. I’m saying that you can’t take a very cheap DAC and fix its layout problems by plugging in an uber expensive external clock. Layout issues with correlated jitter can’t be fixed by reducing random jitter. 
Sounds like a great story though. 

Jon,

A good start for a white paper 😂

[gmgraves]

On 3/14/2020 at 6:59 AM, jabbr said:

This really makes the point that it’s how the ESS is implemented that affects the sound, as Charles Hansen always said. 
 

Too often a part is marketed. My experience also testing some low cost DACs, often with ESS chips. I’ve never typically liked their sound. Same point for using a clock. It’s not the clock specs that matter, rather than how the clock interacts with the entire circuit. Those mundane details are important!

I agree. I have never really liked the ESS sound either. I have a new Schiit Yggdrasil (R2R) and an Oppo 205. The Oppo has ESS SabreDACs. I use the Yiggy for LPCM, and the Oppo to play SACD and DSD files. Of course, I can use the Oppo to play LPCM too, if I wish. This has given me the opportunity to compare 24/96 LPCM files on both the Yiggy and the ESS chips. I find the ESS DACs to be very “hard” sounding compared to the Yiggy, and I was able to borrow, from a friend, a Benchmark DAC 3 also using the ESS SabreDACs., and noticed the same signature hardness. 

 

[Norton]

On 3/16/2020 at 1:01 AM, gmgraves said:

I find the ESS DACs to be very “hard” sounding

As an owner, I would agree with you in terms of the Oppo 205 sounding comparatively “hard”, but I’ve wondered before if that is an objective flaw or just the sound of a  “warts and all” accurate DAC?  According to both Amir  and @Archimago the  Oppo measures very well.

[gmgraves]

1 hour ago, Norton said:

As an owner, I would agree with you in terms of the Oppo 205 sounding comparatively “hard”, but I’ve wondered before if that is an objective flaw or just the sound of a  “warts and all” accurate DAC?  According to both Amir  and @Archimago the  Oppo measures very well.

Yes, it does measure well, but as I said earlier, I can listen to a recording via the  Oppo 205’s DAC, the latest Yggdrasil, or the Benchmark DAC 3 (the Benchmark and the Oppo both use the ESS SabreDAC pro) and both the ESS based DACs sound remarkably similar, that is to say somewhat hard and metallic, while the new Yiggy is as sweet as a mother’s kiss from bottom to top!

 

[pkane2001]

44 minutes ago, gmgraves said:

the new Yiggy is as sweet as a mother’s kiss from bottom to top!

 

A lot of harmonic distortion might just sweeten the sound a tad 

[jabbr]

44 minutes ago, pkane2001 said:

A lot of harmonic distortion might just sweeten the sound a tad 

 

Does harmonic distortion at <-80 dB correlate with listening pleasure? 

 

Perhaps the "ESS" hump is more of a listening speed bump than a few short hairs  

[sandyk]

52 minutes ago, pkane2001 said:

A lot of harmonic distortion might just sweeten the sound a tad 

 

 No. At least it shouldn't in this case, as there are way too many higher level odd order harmonic products.

 You would need a surfeit of even order harmonics to do this.

[pkane2001]

14 minutes ago, jabbr said:

Does harmonic distortion at <-80 dB correlate with listening pleasure? 

 

We'll find out when Archi's internet blind test results are published

 

[pkane2001]

7 minutes ago, sandyk said:

 

 No. At least it shouldn't in this case, as there are way too many higher level odd order harmonic products.

 You would need a surfeit of even order harmonics to do this.

 

Are you sure that George doesn't prefer high-order odd harmonics?  Maybe that's what makes it sound sweet to him?

[jabbr]

4 minutes ago, pkane2001 said:

 

We'll find out when Archi's internet blind test results are published

 

 

Well I can assure you that the SIT-2 he mentions (I have the monoblock SIT-1) is even smoother than a baby's bottom -- babies come over to polish their bottoms on it  -- that's why I have 2!! 😂😂😂

[pkane2001]

Just now, jabbr said:

 

Well I can assure you that the SIT-2 he mentions (I have the monoblock SIT-1) is even smoother than a baby's bottom -- babies come over to polish their bottoms on it 😂😂😂

 

My Pass Aleph 1.2 mono-blocks are even smoother, but no baby will sit on them without getting their bums burnt or legs scratched by the sharp heatsinks. That amp is a health hazard, even before you get a hernia trying to lift it!

 

[gmgraves]

4 hours ago, pkane2001 said:

 

A lot of harmonic distortion might just sweeten the sound a tad 

What’s the date of this test? The newest Yiggy has less distortion than the previous one (according to Schiit). It’s difficult to tell because Schiit doesn’t differentiate Yiggy models with nomenclature like “MKII” or “V.2”. 

[pkane2001]

1 hour ago, gmgraves said:

What’s the date of this test? The newest Yiggy has less distortion than the previous one (according to Schiit). It’s difficult to tell because Schiit doesn’t differentiate Yiggy models with nomenclature like “MKII” or “V.2”. 

 

From the chart, Oct 8, 2019. Seems to be the latest posted on Schiit site: https://www.schiit.com/public/upload/PDF/Schiit DAC APx555 Standard Test Suite_ Yggdrasil Analog 2_Gen 5.pdf

 

[sandyk]

4 hours ago, jabbr said:

 

Well I can assure you that the SIT-2 he mentions (I have the monoblock SIT-1) is even smoother than a baby's bottom -- babies come over to polish their bottoms on it  -- that's why I have 2!! 😂😂😂

 

 One for each channel, or one for each baby ?

[The Computer Audiophile]

@vortecjr has been given moderator rights to this thread in order to keep it on topic. 

[bobbmd]

My DAC (Yggy GS) does with each dram of Logavulin