McIntosh MC275 vs Dynaco ST70

More fun to be had modding the input/driver board on the ST70! I have one like that with upgraded caps and three dual triodes in place of the two 6GH8's. 

@viridian : You sir are correct! I said 6GH8 because I couldn't pull the correct 7199 out of memory. Either will work on that input/driver board, with some re-wiring for the different pin-outs.

@rankaudio nicely done.  I enjoy your youtubes and have a Will Vincent ST-70 myself.  Kenny's builds look great and keep up the good work.  

Ok I can chime in here, I have owned both and do own 3 Will Vincent St 70s. one in triode. It depends on speakers and preamp, both are great amps, here is my analogy, as a football fan, the MC275 is like Jim Brown, one of the all time greats

The restored St70 is like Gale Sayers, also one of the all time greats, but boy do they run the pigskin differently.

With a proper and preferred tube preamp, and dynamic speakers, the MC275 has muscle and power and goes deeper, just like Jim brown with my Khorns, I would choose the ST70 every time, finesse, cut , dance and clarity with a run to the end zone, just like Gale Sayers.

I think @viridian covered it pretty well. I appreciate the ST-70 design but most of the original units sound pretty noisy, by today's standards. Especially the user-built kit amps. The new ST-70 clones can sound pretty good but they have a specific sound that you will either love or hate. You will want to this ampo with fairly sensitive 8 or 16 ohm speakers. 

In the same vein I love the build quality of the MC275 but it's not my favorite Mac tube amp. Yes, the new reissues do sound quite a bit different than the originals. But it's a great amp for somewhat efficient 4 ohm speakers.

To my ears and with 8 ohm speakers the used (old school) MC225 and MC240 are more enjoyable than either the units you mention. But that's me. YMMV