Chord Dave or Ayre QX5 Twenty DAC???

Winson, totally agree.  Many DAC makers are starting to offer these soft and hardware upgrades. If they didn't, I don't think their sales would be quite as strong.  I would not purchase one from a company that wasn't going to do updates and then wouldn't offer them.  Makes no business sense as the companies can earn a bit extra cash, but keep their users very happy and content and not wanting to sell off to get the DAC of the day.

Yes, a big part of the BoM is the chassis and power supply. No need to throw those away for software and minor hardware changes. Many are going modular now and the hand built guys always could rip out and replace the innards as things advanced.  

Plus brand loyalty is important to keep your revenue streams going.  So many high end purchasers have no problem with a 7-10 years life span for their product.  This way we can do a fairly inexpensive refresh around year 5 or so and keep the gear for at least 10 years, sell used and roll that into the NEWEST tech.  All I know is that every upgrade Ayre has offered (I went from AX7 to the evolution upgrade and then from the AX5 to the twenty upgrade) has been a game changer for them. Just huge upgrades.  I feel the 20 upgrade took the company to the upper crust of high end audio.  Just great values.  I'm sure many of you feel the same about the products you own.  As you basically stated, if and made, they can usually upgrade, but only if they can physically fit it into the box (yes, I had a DAC that wasn't going to fit the box, but eventually he said it would).  The only problem I have with the smaller companies at times is that they often are month's to a year or more behind in getting product out, especially if they have life circumstances that get in their way.  That's one reason I moved on from my original DAC to the Ayre.  I was a great great sounding DAC and I was going to do the upgrade to the new state of the art one he came out with, but it was going to take way too long to get done and he's a one man show with someone helping and if things happen, who's going to work on it etc...  again, that's just ME and MY concerns with the smaller companies.  We all know what we are getting into when making our purchasing decisions.  It's all good as it's pros and cons on each side.

Personally I think the Chord Dave is overpriced.  I heard one through very nice headphones at the recent Bristol exhibition.  No doubt it sounded good but so did the new Sony Dac at a fraction of the price. 

A shame really cos Sony in 2017 has not got the perception of making genuine High End gear but they do.

I've always wanted to hear their high end stuff, but never seen it even at the Sony stores.