The originators of  Pioneer Electronics Corporation chose this name carefully, it was the one word that best described their ambitions. It was much more than a name it was a motto that they would strive to fulfill in every product they produced.  Today, Pioneer is recognized as a leader in technology advancements in the consumer electronics industry because of their undying determination to live up to this name. They have numerous “World’s Firsts” credited to them and they have greatly influenced and excelled the path of audio componentry. Over the last 65 years they have created countless imaginative and first-rate products which have irrefutably won the hearts, and ears, of the world’s elite audiophiles.

The SX series is arguably  the greatest stereo receiver line to ever come out of the Hi-Fi Golden Era. These receivers were built to the highest standards and capable of the utmost sonic performance, while remaining extremely flexible. They ranged in size and power from the modest SX-400 series to the massive SX-1980

The SX-1980 was Pioneer’s all time largest, and best sounding stereo receiver. It is always included in any discussion about “the best receiver made” and is, in the eyes of many, the indisputable winner of the receiver wars that began in the late 1960’s.

By the mid 1970’s the stereo receiver wars among the top 4 producers were in full swing. Marantz picked things up a bit with the introduction of the legendary  2500 in 1977, and one year later in 1978 Pioneer answered with the SX-1980. While the 2500 was revolutionary, Pioneer engineers were motivated to outdo it from all angles, and they certainly pulled out all the stops.  The Sx-1980 was a true no holds barred, 12th round effort that was built to be the best, regardless of cost.

If you remember the Pioneer SX-1980 you probably wanted it. It was on the wish list of many, yet out of the financial reach of most. In 1978-1980 it had a selling price of $1,400.00, which was a lot of money when considering the average Income per year was $15,000.00.  

Sonically the Pioneer SX-1980 is a masterpiece that puts to shame many of the high end separate components of today. It has an obscene amount of power, yet not at the expense of musical fidelity.  Unlike some of Pioneers 70’s era competitors, the SX-1980 output was not about numbers on a paper, its power is pure and effortless, music from all sources is natural and thoroughly musical. The tuner section is probably the finest you will ever find on a stereo receiver, again no corners were cut in any design element of the SX-1980. Some of the many features and functions of the SX-1980include; 

 

• Pioneer's "DC with a Difference" Circuitry: Lower TIM Distortion and Less NFB Phase Delay

    You' ll be surprised how truly effective Pioneer’s "DC with a Difference" power amp design is in eliminating the kinds of irregularities and instabilities which cause poor musical performance in less elaborately engineered amps. Here is their " secret" in not-too technical terms: First, we must recognize that no electrically-reproduced sound is truly DC because a DC signal is, by definition, one with a frequency of zero Hertz, and thus has no sound at all. If you were to build a true DC amp it would, also by definition, contain no coupling capacitors whatsoever between its stages. This would eliminate all chance of capacitor-caused phase delays and other problems, and would permit the amplification of the ultra-low frequencies down to zero Hz easily. But, because it is highly undesirable to amplify true DC signals in audio equipment (connected speaker systems would suffer immediate and severe damage if you did), no commercially available audio amplifier at this time uses such a design. Instead, the various kinds of so-called "DC" amps today eliminate some, but not all, capacitors. In Pioneer's "DC with a Difference" design, however, they've  opted to retain the input capacitors for reasons of practical safety. More about this key point later. But instead, we've removed the NFB or negative feedback capacitors. In this way, each individual amp stage in the power amp can amplify a DC components, should one be present, but more importantly, can also handle any signal of a frequency down to DC. But because the power amp has an input capacitor, the DC component (if any) is itself removed while the other frequencies, including the very low ones, are sent cleanly to your speaker systems for reproduction. The reason for wanting to remove capacitors in the first place, remember, was to prevent capacitor-caused phase delays, otherwise known as " time lags." In the signal path itself, such delays usually do not seriously inhibit musicality. But in the NFB circuitry they can and do. This is because NFB returned to the signal path to remove excessive distortion arrives too late to do any good; in fact, the delay results in still more problems because it invariably "corrects" the wrong part of the signal. Thus capacitors in the NFB circuit cause signal deformations called Transient Intermodulation or TIM. Also as the result of the elimination of the capacitors in the NFB, circuit stability is far better than found in ordinary AC amplifiers. This is because the phase delays, caused by "time constants" formed of the capacitor and resistors in the NFB loop, are gone. As said, Pioneer retained the input capacitors in our "DC with a Difference" power amplifier. Thus every dangerous DC component in the signal is prevented from flowing from one stage to the next. The Pioneer advantages are many:
  (1) Connected speakers are protected from DC-caused breakdown. 
  (2) Tonal quality is not harmed by DC in any way. 
  (3) Our use of selected input capacitors ensures that tonal quality is maximized at all times. 
  (4) Low-frequency transient current, generated inside the preamp section when the unit is on and oft, is eliminated. Noise is entirely avoided. 
  (5) Musical inputs sound cleaner and more natural even when you play warped records, because the Pioneer design automatically cuts out the subsonic "rumble" on such discs. Finally, Pioneer's "DC with a Difference" receivers offer excellent regulation of counter-electromotive force, meaning that connected speakers are more effectively damped for overall cleaner, more pleasant sound    

• Advanced Amplifier Configurations for Power and Flat Amps

  The power amplifier configuration used in the Pioneer SX-1980 may be described as cascade-connected, current-mirror-loaded, differential amp with a three-stage, Darlington triple-parallel push-pull direct-coupled OCL circuit. And it uses no fewer than six high-qualify power transistors per channel , mounted on large and specially-designed aluminum die-cast heat sinks for reliable operation. The flat amplifier, too, is DC configuration.      

• Dual Power Supplies: Independent Left/ Right-Channel Supplies Ensure Lowest Possible Crosstalk  

  Pioneer's SX-1980 has a huge toroidal-core power transformer with separate windings to supply the left-channel and right-channel circuits independently. This Dual-Power design is one of the major reasons the receiver, even with its enormous power output, can reproduce very high-amplitude signals from one channel. At the output are four gigantic electrolytic capacitors, each with a rating of 22,000pF. By the way, Pioneer uses very special low-impedance "Star Quad" wire in connecting the capacitors in the rectifiers and the power transistors in the output. We also use thick, pure copper buses in the ground path of the dielectric capacitors to prevent distortion and power loss. This ensures more effective quality control in the assembly process and prevents the tiny and delicate signals from being affected by magnetic flux when you operate the SX-1980.    

• Power Protection: Total Protection for Transistors and Connected Speaker Systems  

  An innovatively developed Pioneer IC or Integrated Circuit, number PA-3004, is employed in the power protection section of this receiver to ensure constant power stability and prevent on/off switching noise, etc. There is also a unique Surge Killer Circuit to prevent surge currents from the transformer from causing damage to transistors or connected speakers. No DC components are ever allowed to reach speaker voice coils.    

• Twin Power Meters: Independent Left/ Right Peak-Reading Meters on Front Panel

  The logarithmically-compressed scales on these large and accurate direct-readout meters make It easy to read peak power output in either channel instantly. Their scales indicate from 0.01 to 540 watts (8 ohms) without requiring sensitivity switching.    

• Pioneer-Exclusive Quartz Sampling Lock FM Tuning System and Touch Sensor Tuning Knob  

  Our unique Quartz Sampling Lock system, or Quartz-Lock for short, ends FM drift once and for all. Absolutely no changes of temperature, humidity or other environmental factors can cause the de-tuning of an FM station once you've locked it in with the help of this automatic system and its LED or LightEmitting Diode helpers. Here's how it works:
  When you reach for the Touch Sensor tuning knob, observe the three LED indicators in the dial panel. If they are off, continue to turn the knob until the red FINE TUNE indicator lights; this indicates you have tuned within ±8kHz of an FM station. If it's in stereo, the red STEREO indicator will also light. And if it's the station you want, release the knob and the green QUARTZ-LOCKED indicator will light to tell you that the station is locked in to the exact station frequency by means of a quartz-crystal reference oscillation servo system. Pioneer's unique Quartz-Lock gives you the complete assurance of best possible, long-term FM reception from the station of your choice, even if you want to record it in your absence. A QUARTZ-RE-LOCK device is included so that even if you power off the SX-1980, the locked FM station is received with the same accuracy when you re-power the receiver at any later time.    

• Twin Tuning Meters and Exceptionally Smooth Tuning "Feel"  

  You'll notice as you tune that the SX-1980 has a very solid "feel." Our engineers have coordinated the touch perceived rotational movement of the knob with the visually-perceived movement of the dial pointer and the twin tuning meters (signal strength for AM/ FM and center-tuning for FM) to make fine tuning easier still. Rapid "scanning" of the dial is also easy because the tune mechanism is especially well balanced.    

• Very Advanced FM Circuitry: MOS FETs and More  

  No fewer than three carefully selected MOS FETs of the low-noise, dual-gate type are used in the FM front end of the SX-1980. They work with an elaborate 5-gang variable capacitor and a 2-stage RF amp for beautiful FM reception , even in weak-signal and/or strong signal areas. FM sensitivity is an excellent 1.5p.V, while interference rejection characteristics are impressively good, even for an expensive separate tuner.    

• Phase-Linear Ceramic Filters: Greatly Improved Group-Delay Characteristics  

  When Pioneer started making FM stereo tuners back in the 1950s (there was no such thing as "stereo'' before then), far fewer stations were on the air around the world. Thus far less interference and noise threatened good FM reception. Ironically, our part in helping to popularize FM stereo broadcasting has forced us to design better and better ways of shutting out unwanted irregularities. The selectivity of the SX-1980's FM tuner is a very high 80d8 , with distortion only 0.07% or less at 65d8f, 1kHz mono, thanks to the use of this technology. Of particular interest are our new phase-linear ceramic filters. They have excellent group delay characteristics to ensure top musicality    

• Pioneer-Exclusive Tuner ICs-PA- 1001 A/PA-3001 A/PA-1 002A

  Pioneer developed very special integrated circuit units for use in their finest tuners, and in the SX-1980 receiver. There is one in the FM IF stage, another in the audio amp and FM muting section, and a third to incorporate the PLL stereo FM demodulator to handle stereo separation chores with far more stability and less distortion than ever before possible. The latter also includes a built-in Pilot Signal Canceller to ensure an entirely flat frequency response up to 15,000Hz.    

• Additional FM/ AM Tuner Highlights

  Movable dial markers help you " remember" your favorite FM and AM stations' location. Five pushbutton switches are provided: AM, FM,FM Muting, FM 25usec. de-emphasis (for Dolby FM), and one to switch the tuner so that any multi path reflections can be detected audibly to help you realign your outdoor antenna.    

• Phono Equalizer: Super-Low-Noise FET Circuitry and Phono Interference Filter  

  You may have noticed that certain  hi-fi records have astounding dynamic range and frequency response. If you haven't heard the difference, you haven't been listening to Pioneer, because they’ve been keeping ahead of the improvements by re-engineering all their phono equalizers with particular attention to very low noise, very high accuracy RIAA equalization. In the SX-1980 Pioneer developed a new super-low- noise FET, equivalent to five ordinary low-noise FETs, in the one-stage differential EO amp. This raises signal-to- noise ratio to an unprecedented 87dB IHF. The resulting performance is so good, in fact, that they included a Phono Interference Filter Switch (on the back panel) to filter out interference in circumstances where stray radio frequencies (such as from CB or other transmissions) threaten to cause a slight but annoying buzzing noise.    

• Phono Equalization is RIAA +- 0.2dB: Low-Error Parts Make the Big Difference  

  The wide dynamic range and frequency response mentioned for today's records comes through clean and undistorted in the SX-1980 because the super-low-noise FET is followed by precision AIAA components (resistors and capacitors) over very low error tolerance. These expensive parts are arrayed in a cascade-connected three-stage direct-coupled pure complementary SEPP design for stability and truly musical sound.  

• Phono Cartridge Load Selectors: Pick Your Pick-Up Load  

  There are two front-panel selectors on the SX-1980 for phono load versatility. Three resistances (1 Ok, 50k and 100k ohms) and four capacitances (100, 200, 300 and 400pF) may be selected in any combination to allow you to use virtually any phono cartridge of your choice for ideal results. These work with the Phono-1 inputs only; Phono-2 load is fixed at 50k ohms, 100pF. The Phono-2 front-panel button, by the way, also serves the separate microphone circuit.    

• Twin Tone Controls: Main/Sub Controls for both Bass/Treble, plus Tone Off Switch  

  Both the Bass and the Treble sections of Pioneer's popular Twin Tone Control system have two separate controls to give you more accurate handling of tonal nuances. The two controls for the low-frequency or Bass range operate at 50Hz and 100Hz respectively; for Treble the controls are 10kHz and 20kHz. Together they permit a total of 3,025 different tonal combinations. Controls are click-stopped for convenience. A Tone on/ off switch permits instant " defeat" of tone control adjustments for flat response.    

• Precision Attenuator and Other Special Features

  The large Master Volume control is the professional attenuator type with 32 click stops and a smooth handling “feel” Filter switches are provided for High (8kHz) and Subsonic (15Hz) with sharp, low-cut CR active type circuits.  

• Three Stereo-Pair Speaker System Selection

   

• separate Lever Switches for Tape-1 and Tape-2, with Duplicate Switch for copies in either direction

     

• Adaptor Switch/ Circuits

     

• Mode (Stereo/ Mono)

   

•   Loudness

  Description here  

• Audio Muting (- 20dB)

     

• Jacks for Mic (mono) input and Headphone (stereo) output

     

• Attractive Walnut Veneered Cabinet

• And Much More!