Audiolab 8000Q preamp?

I purchased a used Audiolab 8000Q pre-amp about three months ago for $450 at a store that sells both new and used items. I am very pleased at the smoothness of the sound. It did not have an owners manual with it and I am in the dark about the product. Does this company produce durable products? The salesman told me to keep the audiolab turned on all the time even when not listening playing music. I am. Is this the correct proceedure for a pre amp of this type?

Thanks for the answers. Another question, during March of 2003 I will give a gold watch to my Hafler 500 which is at least twenty years old and look for an amp to power my B&W 620i's. My buget will be $1,000. Any suggestions as to what good quality used amp to look for to go with my Audiolab? As far as power 100wpc or greater should be enough. I am aware that I can pick up a new Rotel at 200wpc at approx. $1,000. If I can pick up a used amp that sounds significantly better I will do so. Any suggestions as to what brands to investigate in that price range?