Hairball Audio’s DIY-990 is a derivative of the JE-990 discrete operational amplifier. Since being designed by Deane Jensen in 1979 and released into the public domain, the 990’s many revisions have found their way into many high-quality audio designs such as the Jensen Twin Servo and Hairball Audio Lola preamps. The kit includes all the parts necessary for completion of a working DOA.

Hairball Audio DIY-990 Features:

• Designed to the exact specifications found in Deane Jensen’s 1980 JE-990 AES paper
• Comes with pre-soldered surface-mount transistor and bypass capacitors; through-hole components must be installed by the builder
• Suited for use with 15/16V power supplies- R10 and R11 may be swapped with 62K resistors for operation with 24V power supplies
• PCB designed by Mnats, made in the USA

Price:

• $25 for DIY kit
• $50 for assembled/tested unit

More Information:

• Available from Hairball Audio
• View GearSlutz posts by John Hardy and Steve Hogan detailing the origins and design of the 990