Thanks for your response.I am using a Naim Unity Core server with a wave Storm Coax to the ANK.
Main problem is that being a tube DAC the ANK takes a long time to warm up.Even after switching on and playing music for around half an hour before listening it still doesn’t settle down for some time.
Thoughts are that by going S/S things would warm up quicker and that R2R ladder DAC would be best option.
I will certainly take on board what you state about targeting supermarket customers and that both the Gustard and Holo aren’t what they claim to be.
Only worry about the Pontus is that most of the reviews state that burn in takes a long time.
At 83 years old do I have enough time left to enjoy the DAC!!!!!!!!!!!!!!
Not only Pontus, more about later. Discrete ladder DAC needs 500÷1000 hours burning before sound is optimal. After such period if used regularly, can be powered off for a night and next day it needs just 30 minutes to get temperature stabilised. It doesn't mean it is not listenable when switching on, like it is during a first week of intial burning. However some people keep their DAC powered on all the time, it is not good for tubes. Tube DAC can be modified, so the power switch will affect only a tube output section, but no-one bothered with such idea, as integrated ladders in chips require less burning time.
It is why when I hear that sound is not stabilising for longer time, I suspect ANK needs a service to check whether solder joints are not cracked (it happens regularly on tube sockets) and internal components are still in a good condition, especially capacitors. Audiophile grade capacitors can deteriorate quicker. If you like a sound, it can be worth refurbishing.
Extra comment about Pontus, it is normal, predictable. Abnormal when there is no warming time. That's correct!
Some brands pollute sound with extensive ultrasonic spread spectrum modulation. It is a method to linearize ladder errors, it also reduce warming time. Measurements look better on the FFT, as analyser output is averaged over thousands samples, spike peaks are blured with a floor noise. Sound becomes more smooth and it can cause dizziness over a longer session. In a case of the most pervert brand Holo, sound is more close to Delta-Sigma DACs than R2R. Reviewers avoid comparison with other R2R brands, they rather chose Delta-Sigma.
I am writing this all, as this thrend has short legs. It is already seen that most of users of a modern implementation of R2R DAC start using powerful PC to convert PCM content to a high speed DSD, it is bypassing R2R ladder completely.
Denafrips use traditional approach, there are no opamps in the audio path, while there is a confusion among users how it should sound, as different versions of a firmware do not bring definitive answer. Audio GD is the old school in silicon design, but sound is more modern, brings a bigger punch and excitement. There is no money spent on advertising, it leads to a great value. I recommend R-8HE if you don't have already power conditioner in the room. It is their basic model for a high-end setup. There are three R-27 models with the same DAC section as R-8 and a headphone amp. If you decide to spend more, you get a larger enclosure, better power supply, but in this range there is a model with four (or eight?) PCM1704-UK chips!