Billimbriale....It has been my observation over the years that the used market price is more relative to supply and demand than sonics. Demand is not always based on sound quality, but rather what is currently popular. Of course there are many factors that lead to popularity and as you well know what is popular to today may be out of vogue tomorrow regardless of how good it may actually be. This is a fickle hobbie to say the least. One of the reasons I believe you can get such low prices on the Audible Illusions is due to the fact that there are so many of them out there. This is one very successful preamp design. If the supply exceeds the demand the prices go down. Most people do not have a lot of patience when it comes to selling and will often take less just to move something fast so they can move on to what's currently popular. CJ is best known for its tube designs, not so much for solid state. There are far fewer PFRs out there on the used market and that combined with CJs reputation probably has more to due with the used price than the sonics. That said, these are both really good products, but as I stated earlier there is a very good reason why Audible Illusions has sold so many preamps over the years and why they have always had such great reviews. It's because they have been, and continue to be, one of the best designs out there regardless of price.
