The Best, Biggest, and Baddest Receiver Pioneer Built: SX1980 Restored with upgraded Delta-9 Power Supply and Recapped

There are a few pieces of vintage audio equipment that are legendary;  the SX1980 was the largest and most powerful receiver Pioneer created.  Without a doubt, it is simply stunning.   SX1980s don't come up for sale very often. When I was afforded the opportunity to purchase an example in excellent original condition, I couldn't resist.   It sounded good and ran cool aside from dirty controls.  After a few hours of testing I began a mild restoration to ensure many years of reliable audio nirvana.   I knew the receiver was serviced sometime in the past because the dual-zener modification was made according to the Pioneer service bulletin.  The original power supply board also had some markings for transistor configuration as if somebody worked on the power supply at one time.   The power supply board is a great design, however, it does have a few flaws from the factory.  Many very talented technicians developed methods to upgrade the circuits over the years.  Recently, a company called