Next best exponential DAC quality level?

That’s absolutely correct. Then why do you and others keep insisting that a tube based DAC is inferior, has poor SQ compared to SS? Oh yeah, it’s the specs.

An example of a well built, well implemented DAC is made by Audio Note. The designer has said they measure and spec the device, then they tweak it during a listening session until it sounds like real music. They use masters as their sources.

What exactly is "well-implemented" in Audio-Note DACs?  It is quite obvious that measurements play little into Audio-Note's design process. These are not DACs designed remotely for accuracy. Their performance w.r.t. accuracy would put them right about 1983.  Here is there 4.1x CD player:

https://www.stereophile.com/content/audio-note-cd-41x-cd-player-measurements

• Poor SNR
• Poor output impedance causing serious frequency response droop
• Poor power supply harmonics rejection
• Poor channel isolation at lower frequencies
• Large amount of ultrasonic noise converted into audible noise
• Somewhat significant amount of spurious low frequency noise
• Terrible intermodulation distortion
• Nasty levels of jitter

Just what part of it is well implemented?

Devices using the ES9038PRO chip include the ~$99 Khadas tone board, the ~$14,000 Lumin X1, and many others at price points all over the map. Same DAC chip (or different versions of the same DAC chip) with many different implementations and collateral features. What do you get for nearly $14K with the Lumin X1?

You get transformers on the output complete with hysteresis and all kinds of other nice "tubey" artifacts. It does not cost a lot of money to implement an accurate DAC. It is when you don't want it accurate that it costs a lot of money. This is the art/reproduction thing. Their marketing blurb is impressive (Dual Sabre DAC featuring 140db dynamic range --- yes, the chip can, their unit?), and all kinds of superlatives, all rendered meaningless by transformers.

$99.00 laughing my tits off! I've spent over 20x that on speaker spikes. Ffs get with the program or have a ear transplant.

OP here...   

But that's the whole point of the thread -- for $99, in my listening space, with my setup, I was surprised that it held it's own so well.  Sure there were differences, but none worth 4x / 8x the price. 

Which brought the original question:  For $99, the Toneboard was decent and well respected in my listening space.  What's the next level DAC (considering my setup)?  I had originally thought that the M500 or Hint6 would be that next level, but was surprised that it was not.  

I appreciate the thoughts on source material.  I'll have a look at Qobuz this weekend and run another test.  

@jjss49  +1  The whack a ment games have commenced.

@martinman Hey Buddy a lot of folks have been in this hobby a long time and I do apologize I shouldn't of said what I did. However we are talking apples and oranges here. Our Nirvana is getting breathed upon by Lennon, Jagger etc. Can you imagine how it feels sitting next to John Lennon? It's yours for $50k+. It really isn't possible much short of that price point. Please go and make an appointment with several dealers that sell really high end gear and realize what is possible. : )