No More upgrades to ARC LS25 Mk.1?

Yup. I'll contact GNSC. While they may to certain upgrades, I doubt they would do the Mk.1 to Mk.2 upgrades given the parts involved (e.g., new front and rear panels).

sell your Mk1 and buy a used Mk2, it will be way cheaper... they are built using two diffent tube set designs...6922 versus super tubes..

Well if it's new front and rear panels you're after, I agree with Cytocycle.
I was simply under the impression you were looking to improve the performance of your LS25 Mk I, I guess I was mistaken.

Cheers,
John

JMC:

My bad regarding front and rear panels. That's not it.

Of course I want to improve the performance of the LS25. But, I think the jury is out as to whether the Mk.1 with new 6922's from upscale audio is better or the Mk.2 with the JFET/6H30 is better.

Edwyun: So now are you asking now which is better Mk1 or Mk2?
There are tons of threads on this...
Mk1 Warmer top, and a more classic ARC sound

Mk2 Better Bass, more solid state sounding compared to the Mk1 but also slightly more detailed, but some feel it's missing some of the magic of the MK1

Then you will have the third group that feels the ARC LS5 MIII it the best of both worlds...

My feeling is which one is going to have the best synergy with your system. Determining what you feel is lacking and what you want to improve or change will be the real question.

Search the archives for tons of comparisons.

I have been dissappointed (value and quality of tubes) in upscales tubes in the past... there are plenty of threads suggesting other tube sources.