Upgrade Hafler 9500 or Mccormack DNA-1 for Thiels

The guru I am hoping reads this would have heard both and would also be able to comment on how each would sound compared to the C-J

I doubt you'll find such a guru; but, here's my 2 cents: I have no experience with the Hafler or DNA - upgraded or stock, but I do have a pair of B&K Mono blocks that I had John upgrade. I fretted over whether to spend the $ for the upgrade or not, and tried many more expensive (but used) amps before doing it. In the end I decided to go, and I still use (and love) those amps.
Recognize though that when you pay for the upgrade it's like buying a new amp, and when you go to sell it you will get only a fraction of what you have into it. I haven't seen any Hafler 9500's with Hillig's upgrades sell, but have seen 500's sell for only a little more than stock versions. OTOH, I've seen upgraded DNA 1's which definitely sell for much more than the stock versions. This would be a consideration for me.

I also see/read a lot more about the DNA-1 in the context of great amps, and have never seen a similar regard for any Haflers.

Finally - if I were you (FWIW) I would be inclined to just a/b the stock 9500 with the stock DNA-1. Which ever one win's the shoot out is the one I would go with. I would also keep a close eye on the classifieds for an upgraded DNA-1 and maybe buy one used and try it. This way if I wasn't completely happy I could flip it for little.no loss $.

Bdgregory makes an extremely good point - since you have a DNA-1 on the way, you will be able to audition both amps in stock form. The amp you prefer stock is the one you should stick with.

Most upgrades (certainly my own) improve on what is fundamentally there to begin with. It would be unusual for an upgrade to transform the basic character of an amp into something else entirely. Listening to the stock amps should tell you a lot, and my guess is that you will find you have a clear preference for one or the other.

Best regards,

Steve McCormack
SMc Audio

I've heard them all with the Thiel 3.5's, but honestly don't remember the sound of the Hafler with them. To my ears the c-j worked best. The McCormack, while a perfectly lovely amp with other speakers (Vandersteens!) were too forward and shouty to my ears with the Thiel 3.5's. IME, the warmer bass of the c-j works better than the tighter bass of the McCormack with the 3.5's too. At this price range you might be able to find a Threshold S/500, a very worthy consideration that should work well with either your Threshold or Audio Research pre.

Years ago, I used a pair of DNA1 deluxe edition rev.A mono block to power the Thiel 3.6s - sound very dynamic, great transition attack and on the neutral side. I hardly felt the DNA ever out of juice even thought the Thiel was among power sucker.