Need recommendations to replace ARC VT100 MkII

As long as there is nothing wrong with your VT100, I would keep it and get a better preamp. That will make a huge difference. Also, what type of maintenance are you talking about? Aside from replacing the tubes every so often, you shouldn't have to do anything else to it.

The DC balance adjustments are somewhat of a pain. I love the tube sound, but the VT100 MkII is not particularly user friendly.
ZD542, what would you recommend for a preamp?

For a low maintenance tube power amp with great sound, look into the Music Reference RM200. Its tubes are mounted on the amps chassis, not circuit boards. Very bad idea, ARC.

I made the jump from Audio Research products to Jeff Rowland and really have not looked back. Certainly is nice not to have to worry about tubes, heat and reliability. This really is not a jab at ARC, it's just that the difference between quality solid state and quality tube products are in my judgment more a matter of taste than absolute sound at this point.

I can respond to Bpd24's answer, since I own both the RM200 and VT-100 Mk2 and have for the past few years.

The two amps share much more in common than not. In other words, they're not as different as you might think. The RM200 (with 6550's) seems to have a little better clarity and treble extension, and a more accurate-sounding bass. The VT100 has a fuller sound, while simultaneously maintaining good detail. Its bass is more authoritative.

Note that I've referred to 2 tube amps (well, the RM200 is a hybrid amp) with terms to describe their bass that you wouldn't expect of tube amps ("accurate" and "authoritative"). While you often expect to hear tube amps described as "loose" or "nonexistent", neither of these two amps has any problems with their bass.

The RM200 is certainly easier to tube roll (the difficulty with tube rolling in the VT-100 is either a pro or a con depending on your take on it). Note that the RM200 has ONLY balanced inputs, which is no problem for me as I have an Audio Research LS-5 preamp which has only balanced inputs and outputs. The VT-100 has both single-ended and balanced inputs.

You might find the RM200 to be more of your cup of tea, but in my opinion if you want a substantially different sound you might look to another amp (possibly SS).

That's just my 2 cents.

Michael