Hafler XL600 Vs Hafler 9505 Much difference?


Hello all, I am new here and still learning to navigate the website. I have been out of audio for a number of years. I had an old Hafler XL600 years ago and really liked it for the price. I am thinking of getting into audio again and am considering purchasing either an XL600 or the newer Hafler 9505/9500. I have read there have been a lot of improvements in amplifiers in the last decade. Is that true? How much difference is there in the amps I am refering to? Would I notice a difference between the XL600 and the newer amp? I hope to purchase Boston Acoustics VS336 speakers to go with this.
Any info would be helpful.
Thanks
sundriednm
Rodman, I take it I could use the FRED bridges in my Acoustat TNT200s also? The 9505 is essentially the TNT circuit. Sonically, what is the improvement?
Mainly; a greater sense of dynamics, faster/more tuneful low-
end, less noise(some call it, "blacker background) and a
smoother/more detailed top end(not to say muted, recessed or
falsely accentuated in any way). They also allow upgraded
fuses and PCs to show off their benefits more obviously.
There are a few electronic manufacturers that offer them, as
an upgrade. ie:
(http://www.aebycary.com/shop/upgrades/hexfred-rectifiers/)
(http://www.rogueaudio.com/The_Magnum_Series.htm) Of course;
upgrading your filter caps adds to the improvement too.
Parts Connexion also offers these rectifier PCBs, so you can
more easily do a discrete HEXFRED or Schottky bridge:
(http://www.partsconnexion.com/kits_sub_assemblies.html)
(http://www.partsconnexion.com/rectifier_diode_cree.html)
Talk about a trip down memory lane; the Hafler 9500 and 900 series pre coupled with a pair of Acoustat welcomed me into this wonderful hobby 28 years ago...

Wig