Just back from Aesthetix with upgraded ic boards, capacitors and firmware bring this up to the current spec. In addition, all tubes have been upgraded to Sovtek, at $100 each. Tubes have about 400 hours on them. Unit is very clean with no scratches or blems and performs perfectly. Kept in a child, smoke, pet free environment. One of the best preamps, ever. The Signature is something special and one of the best values in high end audio, making this a bargain that can take a system to a whole new level of musical excellence. Lists for $7,500 making the asking price very reasonable at $3,988.