Tuner or Receiver


I'll preface my main point and question by saying that I recently bought a used Yamaha RX 596 Receiver which is around 15 years old.  After biwiring my Castle Conway 3 Towers to it, I have been blown away by the sound from this system.  Far better than any previous amp I've used with these speakers and probably due to the 85 wpc vs 60 wpc or less and only using a single speaker cable for each.  


This leads me to the question about tuners and receivers.  Currently I have a Carver TX11a and also a Onkyo T-4310r.  Both are quite old but still work fine.  But...  Has recent tuner technology advanced beyond the the units from the 80's and 90's?  Is the sensitivity of the AM and FM sections superior these days and is the selectivity also better?  I don't need Digital FM and still listen to analog AM and FM.  Just want to know if I would be better off with a new tuner or receiver that would offer better audio quality or better signal capturing ability?  The tuner in the RX 596 is OK but also dates to about the same time as the Onkyo tuner.  Onkyo seems better too.
will62
Thanks Yogi.  The only real shortcoming then is not having the expanded AM band on either tuner.  As long as the new tuners don't have appreciably better sensitivity or selectivity compared to the two that I have right now then I will stick with them.  The Carver is a bit better with weak signals but the Onkyo is no slouch.

I read some reviews of the new NAD C427 which are quite good.  People claim the FM side is better at picking up weak signals than some older gear like Adcom.  But I know for the money the Carver was about the best tuner made.  Thus, I would probably have to spend thousands today to get something comparable then.
You would be wasting your time and money buying another tuner. A good antenna is worth its weight in gold with tuners! 
No matter how good the tuner is you still need a good antenna.

And the RX 596  is from 1993, long past the "silver era"

I have a Yamaha CR-1020 (1977 - 1980) that has an excellent tuner. You can even tune out multipath distortion (from signals bouncing off buildings)..
I will plan to stick with the Carver and Onkyo tuners then.  Both handle weak signals well.  I will have to set up a outdoor antenna when I can figure out where to put it.