Pioneer SX-1980 MONSTER RECEIVERS

Greatest Pioneer Receiver of All Time

 

 

For serious monster receiver collectors, the SX-1980 with its monster size and sound, is a show horse that literally dwarfs the others. The Pioneer SX-1980 was in many ways the BIG DADDY of the Monster Receiver era. The amplifier section with the boat anchor toroidal transformer and tank-sized heat sinks contributed to a back busting weight of 78 pounds. For handling this monster, we recommend the help of a buddy!! With a true FTC rating of 270 WPC at an amazingly low 0.03% THD, the SX-1980 has a performance specification that compares favorably with today’s best amplifiers. It’s good to know the SX-1980 can easily sweep today’s home theater amps into the weeds. Here are some highlights from the owner’s manual:

The adoption of a single-stage differential amplifier with low-noise dual transistors, a current mirror load and a 3-stage Darlington triple SEPP circuit provides a bumper power output of 270 watts + 270 watts (20 Hertz to 20,000 Hertz with no more than 0.03% THD) which is extremely stable. The power amplifier is configured as a DC power amplifier with the capacitors removed from the NFB circuit for a flat gain response. The large-sized toroidal transformers with their superb regulation emply 22,000uF large-capacity electrolytic capacitors (two per each channel). There are independent dual power supply circuits with separate power transformer windings to provide power for the left and right channels.

The FM front end incorporates a two-stage RF circuit that employs a 5-gang tuning capacitor and three dual gate MOS FETs for high gain and low noise. This configuration excels in ridding the sound of undesirable interference. The FM IF amplifier combines five dual-element ceramic filters…for high selectivity (80dB) and low distortion… The local oscillator includes Pioneer’s very own quartz sampling locked APC (Automatic Phase Control). This output of this extremely precise quartz oscillator is divided into frequencies of 100 kHz and so reception frequencies which are a multiple of 100 kHz are locked at every 100 kHz.

Today, the SX-1980 is relatively common and can fetch $1200 to $1600 or more on EBay. There were at least two production versions of the SX-1980. The more desirable later version featured a sensitivity switch on the back not present on the early versions. Also, the power supply circuit was improved, correcting an early weakness.

 

Double click the thumbnails for the "big picture":

Front	Side	Internal View
Tuning Meters	Power Meters	Back

Written by SoCal Sam of AudioKarma

Images borrowed from an eBay auction.