I have a pair of U273b and some U73b (modded and serviced by Oliver)..
The thing with the German broadcast gear is generally if you find the right units for a good price, you are getting a great used value when you consider the equipment was built to extremely high standards of quality and designed by genius Phd designers - the kinds of people who in the USA would have been working as project leaders at NASA, Lockheed Martin etc...
I think these units would have originally cost in the range of $2k-$4k each in today's money..
With the German broadcast compressors , I think the idea was they were meant to be set up a certain way and left alone for radio broadcast, mastering, live studio recording, etc and dealing with the audio hitting them - so in their unmodded form, tend to be perhaps less handy (in terms of front panel knobs / parameters) in a tracking type situation where you might want to 'dial' in settings..in that respect there's nothing more handy than LA2A , 1176 style compressors where you tweak to taste..
So I find with the U's its better to set them a certain 'standard' way and let them do what they do, maybe making some slight adjustments..
The U273b sounds great and my U73b sounded better and were more useful in different situations after getting serviced / modded by Oliver..
The Sitral-era equipment like the U273b all sounds 'tube-like' even though its transistor..
I'd say the U273b / U73b I have sound similar but the U73b has more of an 'open' tone, mojo and funkiness, sounding a bit better IMO... But - I think the average user will have more of a fun time with a U273b since it will require less TLC and fiddling than an old tube unit like the U73b. Also the U273b seems to be able handle more hitting it without distorting or getting squeltchy like the U73b can do at times..
The new U73b units from Oliver sound very interesting since you will have all the joy, reliability and usefulness right out of the box without all the issues of a 40 year old piece of tube equipment.
