The audio research arc line- from top to bottom.

What about the preamps that came before ls-26???
Are the ls-25, ls-22, ls-17, ls-16 close to the ls-26?????
What will give the biggest bang for the buck?

The LS-16MKII is one of the worst preamps I have ever heard.

"The LS-16MKII is one of the worst preamps I have ever heard."

I totally and completey disagree! The LS16MKII is a marvelous sounding preamp. Very open and dynamic with excellent control. No, it doesn't sound as good as a LS26, but it comes pretty damn close.

Can any old ones be modified so they can compete with the ls-26????
Or what else is available that isn't as pricy as the ls-26?

are you considering buying only new or are you willing to buy used? You can buy used LS-17 or LS-26 and get GNSC mods (http://www.greatnorthernsound.com/) which are specialized in ARC mods. They have a number of people including the founder who worked at ARC for 10+ yrs and are very familiar with ARC designs and how they can be bolstered. In fact they do mods for a whole range of current and older ARC preamps. Go through their website and read what mods they offer and customer testimonials and when you decide which amp you want to hone in on, call Steve Huntley and walk through it with him. Excellent guy and excellent advice. I have no affiliation. I considered going that route but ended just getting a new REF 3 from my LS-26. I am now considering modding my REF3. Hope this helps.