Help chose : Hafler 110 preamp or Carver C2 preamp ??

Try a Stax CA-Z, if you can find one. 

Can't comment on the Carver, but had the Hafler 110 built as a kit by myself. It worked great, but compared to some of the similar pre's of the time, I thought the Hafler was a bit on the hard sounding side, mostly noticed in the upper mids. Was slight, but audible. I purchased a used B&K Pro 5 preamp and found it better sounding. As Ralph says, there are others than these two.

what does the robbergerman NOT have in his vast collection ?

i built so many 110, 101, 200, etc putting myself thru University....a very competent preamp and others have mentioned more “ off the shelf” modification available....

BUT Ralph makes a good point, you have lots of choices...ONE of my favorite low. $ ss preamps is the acoustat RP-2 or in tubes a CJ PV-2
or Ralphs entry level pre.... 

Why these two preamps? Are there none others in the area?

These guys offer significant(and reasonably priced) upgrades, for the DH-110, should you desire. ie: http://www.musicaldesign.com/MC_Haf_premod.html Just FYI: With the 110; an MC phono stage was optional(something to ask a seller about, if a concern). The Hafler is fully discrete(no op-amps in signal path). The later productions(black pebble finish/Rockford) had gold-plated RCAs, metal-film resistors and went to Polypropylene capacitors, from Polystyrene(desirable changes).

I have a Carver and a Hafler preamp in my collection. Along with the Sherwood 6040 amp. I'd say it's a toss-up between the two preamps. Though the Hafler has the pedigree of being designed  by Erno Borbeley (who did all the Hafler SS gear).

I am both a Carver and Hafler fan, but would give the nod to The Hafler.  The DH-110 was just a nice, sweet sounding preamp.

Carver and Phase Linear are very detailed but forward sounding preamps.  It’s like sitting on stage as opposed to 7th row center like most preamps, or row 25 like Marantz.. 

I like it sometimes, but listening fatigue is the order of the day.  Conversely, I could listen to Sansui and Marantz all day long.  Some McIntosh and Citation gear as well.  I would lean towards the Hafler.
it was always well thought of.