For those who don't believe TASCAM made "pro" or "studio" machines have obviously overlooked the ATR-60 series and MS series! Battleships with servo-tension! Tough to beat!
I've got the ATR-60-8 right here :
I never thought of Tascams as being studio machines either, until I've got the chance to own one myself and check it out (I wouldn't usually buy 8 channel machines but it was a bargain I couldn't miss, even though... It's not in full working order). I still don't believe all of them are full pro machines though, but some might just make it into a full pro studio... I'll explain later.
When I got it, it wouldn't record or play a thing so I had to fix it. With some help from people here on AK, I managed to fix it. A surge have been sent through the audio cables and the whole IC control circuit was damaged (luckily it was just the control). ICs needed replacement, together with a few diodes and caps. Now it works, I have 4 fixed audio cards and 4 still to go, but two of them are badly damaged. I'm not using it in a pro environment so I only recorded mastered music on it, using two tracks/two channels at a time, and swapping the cards around for further stereo recording. I will hopefully find some good working cards someday to replace the damaged ones, but there is no rush, I can still use it when I want to.
With the repairing/maintaining process, I've had the chance to study the recorder and it turns out to be a weird half pro/pro combination IMO. The transport is definitely a pro. It's a tank. The preamp was unexpectedly well built too. No wonder some people said they lasted 20 years only with maintenance, but sound-wise... I don't know really. The 4 track/4ch HS version is definitely better sounding as it runs the tape at 30ips/15ips and uses half inch tape. Mine uses half inch tape too but has 8 tracks. That's not very pro :| But not disappointing either. If well calibrated, those cards are working good together, delivering acceptable sound even without the dbx module.
DBX on a pro/semi pro deck? actually, it depends on the engineers. For a deck that needs it, a well-set dbx may sound quite impressing from what I've heard, but personally, I can't see dbx on a pro deck...
The ATR-60-8 works like a pro but sounds like a high end home recorder. I wouldn't put this recorder in a full pro studio. Not even the ATR 60 16 channel, because it's the same story... 16 tracks on one inch tape.
However, the 4 channel and two channel ATR60's , high speed versions, are a different story. Those may count as money saving full pro decks. Also, the ATR-80 is a impressive model with pro features. There is the ms-16 as well, but I would personally go for ATR60-16 if I had to chose (better quality, more features).
I also own the Revox B77 mk2 HS, two track version.
Now this is Tascam's opposite, home transport but sounds like a pro. lol (I'm joking, but it seems to sound better than the Tascam yet it doesn't have the same tape precision).
I guess there is not much left to say about the Revox

We all know what they're capable of.
P.S. It's missing the head cover that's why it doesn't have it on, I'm searching for one right now. And those amps being one on top of the other, they have fans mounted above them so they don't get hot.