Over the years AI have produced thousands of audio preamplifiers which have given much pleasure to music lovers world-wide. Audible Illusions is proud to have been a pioneer in modern single-ended tube design.

• In the early 1980′s other audio companies still manufactured preamps based on the venerable 12AX7 tube with cascode circuits, cathode followers and negative feedback, etc. We were one of a few companies to completely base our preamp designs on the 6DJ8 dual triode.
• Audible Illusions was also one of the first audio companies to incorporate automatically muting turn-on safety circuits which prohibits a tube preamp’s dc voltage surges from damaging audio circuits in case of AC power failure.
• The first audio company to employ bare, oxygen-free copper traces on our PCB’s with Teflon solder masks. We continue to hand-solder our circuit boards with silver-bearing solder.
• A.I. developed a special “filament-on” soft-start circuit which greatly extends tube life.
• We were one of the first audio companies to design very fast, low-impedance FET regulated power supplies to support our audio designs.
• First to develop a stable, open-loop, no-feedback line stage which significantly improved sonic performance of our
  preamplifiers.
• We were first to parallel tube stages to lower output impedance thus eliminating the need for cathode followers.
• And, one of the first companies to use pure film-foil capacitors in our audio circuitry.

Today we take pleasure in noting that most modern tube preamplifiers are based on the 6DJ8/ 6922 triode and that many of our refinements are now used by other audio manufacturers.