What is the best Reel To Reel machine ever built?

Everyone who has listened to master tapes or dubs knows about the well balanced sound they provide. But it is also important to have a fine tape recorder or playing machine to enjoy the tapes' qualities in a good system.
Maybe my question was raised once before but the relevance of the topic is now greater as the tapes are back to more and more audiophile friends, especially those who are owning excellent phono chains.

I have seen many big & professional machines being recently offered and sold on e-bay, Audiogon and other platforms and I am discussing within a small group which machine is really the "holy grail" among the R2Rs. So why not here. I am interested in findings.
I use Sony TC 765 for all my replay....not the super machine, but very good sound and build to last.......
Dear all,
thanks for contributing so far. I know about the Studer machines but there are so many other nice machines out there. I recently saw a vintage Sony prototype on ebay in very good condition, only a little overprized.

Sam, oh yes you are a lucky owner of a A820. May I ask you and Mike if are using the A820 at 30 ips?

Besides of the A820 which machine really has "best of all time status" or which one would you recommend going for?

best & fun only
Even though I myself won't be pursuing R2R (not enough easily available material I'm interested in to play), one thing I would be curious about is what these R2R worthies think of the vinyl vs. tape comparison. Too often, it seems to me, the magic word "analog" is bandied about almost exclusively in relation to vinyl, to which it is not a synonym. An occasional reminder of the difference could be healthy for the perspective, I believe.
I feel that that it is too hard for there to be one best reel to reel. I have owned many. The objectives for me and my reel to reel tape machines are not the same for others who may also own reel to reel tape recorders. I like the three reel to reel tape recorders I own. I have spent a lot of time going through and sorting out the issues my machines had as a result of age, mainly old electrolytics caps. I also spent years looking for new old stock heads belts and other items that fail. All three of my machines sonically are superior compared to all the other reel to reel tape machines I have had owned in the past. Almost all the reel to reels machines I have owned in the past I have been able to sell them to friends and people I know well. One bought one of my previous big fancy Technics R2Rs and according to the buyer the his reel to reel with lots of feature any speed and tape options is the best and that I was crazy to sell it to him and buy three reel to reels to cover my reel to reel tape needs. I have another friend who says the same thing about the big bad fancy Akai, and another friend who bought my vintage done right Ampex. I have to admit that vintage Ampex sounds great but the Revox machines sound even better according to me. These guys are funny when they come over with a newly found treasure usually a prerecorded tape found at a yard sale in great condition. I get grilled "why does it sound so good in your system" then they make fun of my funny looking Revox machines. Anymore who cares about the best, what you like is what counts! The best is an opinion of some one.
you`re absolutely right. Being a connoisseur of R2Rs as I learn from your history you know about "your treasures" quite well. I regard the Revox machines as very good ones too. Nevertheless I experienced that the professionnel studio machines offer some advantages we as home audio guys did not know before.

In my youth I started with Grundig and Philipps R2Rs. When I rediscovered Tapes in the 90ies I first bought a TEAC X2000 and later picked up a Studer A810 in Switzerland but had to calibrate the machine. This one was a true friend for about six years. When I was confronted with one of the best restored Studer C37 R2R I have ever seen I added the C37 and from now on enjoy the tube sound of a studio tape recorder.

I also compared the sound of the C37 with the A820 being able reproducing over 15.000 Hz. The A820 is from my point of view technically the superior unit but musically I prefer a little the C37. This is today`s situation, but who knows...

best & fun only