I thought the reason early CDs sounded so bad was due to the recording processes back then. The existing technology for recording was more customized for vinyl and cassette tapes which are both analog. On top of that the average engineer(or whoever) was more skilled and experienced with analog media than they were with the new digital format. To me that equals that the data on the CD itself was distorted -- not that the CD itself or the player could not faithfully reproduce what was on the disc.
So at the time, because of existing tech, vinyl probably did sound better than CD. But mostly because you had a mature technology vs a baby one.
Thats why I am not so sure about the analogy between NOS dacs and tubes/vinyl. With tubes we are talking about something very simple -- they are either buffering or amplifying - it colors or in some cases softens the sound to some degree but nothing is lost -- tubes are about taste. Vinyl is analog and CDs are digital -- nothing is missing from a vinyl reproduction - CDs are the approximation. No whether you like the vinyl sound is something else.
But with DACs we are talking about something different entirely. A DAC is all about reproducing whats on the CD as close to perfect as possible. Otherwise its not doing its job IMHO.
My own experience with the Havana has swayed me to the OS side for good. I have borrowed my friends Havana twice now. The first time I borrowed it I had a significant shortcoming in my audio system -- my speakers are quite a load and I simply did not have enough power. The reason this is significant is that my amp gets quite brash on the top end when driven hard -- alot of distorted treble energy. The Havana in this system actually sounded on par with my other digital sources albeit with some shortcomings namely soundstage (you can see what I wrote in the Havana thread
STARTING HERE) . The softness of the Havana helped tamed my treble issues and I incorrectly gave credit to the Havana.
Then I bought a second amp and biamped my speakers -- loads of headroom now, no brash top end at any comfortable listening level. Recently borrowed my friends Havana again last week - he had replaced the stock tube with a extremely well regarded tube (the name escapes me). My opinion has completely changed. The Havana is a decent sounding DAC no doubt - but resolution no, soundstage no, top end clarity no, bass yes, transparency no, less ability to decode phase information, overall musical weight/tone yes, detail yes.
Most of the sound seemed to come from one central location between my speakers. A centralized ball of music. Unless you hear the Havana using speakers and not headphones you will not notice this. I imagine that without some sort of cross feed the Havana would sound quite nice on a pair of headphones.
The larger point at least to me is this - I just don't think the Havana reproduces sound true to whats on the disc. It may reproduce a sound that you like (And I very much enjoyed it on some thinner sounding recordings even on my second go around with it) but it is not faithful by any stretch. It is not transparent by any stretch. If I play CDs of material recorded in the 50's they should not have the same basic sound as a recording from last year. "Hey Jude" should not sound like it was recorded in a room full of plush couches.
Again, I am not downing this DAC, I think its good, but out of the 10 or so digital sources (cd players and Dacs -- all of which were OS) that I have heard that are above the $800 price range I'd rank the Havana at the bottom. YMMV especially if you are using headphones instead of speakers. I am not trying to get into a pissing match with fans of the DAC because I can see why you like it, I am just reporting what I heard and felt.
So i think the fundamental question is really what do you think a DAC should do? I am in the camp of "please reproduce my digital music as faithfully as possible" - if I want warmth or tamed highs I will add a tube pre-amp or tube amp. Now I have only heard one NOS DAC obviously but since the Havana is so well regarded I thought my story would have some value.