science

Pioneer SX-1980

Pioneer SX-1980 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pioneer SX-1980 rather than just read about it. In short: The Pioneer SX-1980 is an AM/FM radio receiver that Pioneer Corporation introduced in 1978, to be matched with the HPM series of speakers. It was rated at 270 watts RMS per channel into 8 ohms, both channels driven.

Key takeaways

Pioneer SX-1980 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pioneer SX-1980 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pioneer SX-1980 from memory before moving on to harder problems.

Reference excerpt

The Pioneer SX-1980 is an AM/FM radio receiver that Pioneer Corporation introduced in 1978, to be matched with the HPM series of speakers. It was rated at 270 watts RMS per channel into 8 ohms, both channels driven. However, in the September 1978 issue of the magazine Audio, Leonard Feldman performed a specification test on the SX-1980 and stated in his report:

Though the new [IHF mandated] "Dynamic Headroom" measurement is specified in dB, it should be mentioned that based upon the short-term signal used to measure the 2.3 dB headroom of this amplifier, it was producing nearly 460 watts of short-term power under these test conditions!

At an official rating of 270 watts RMS per channel into 8 ohms with a measured 2.3 dB dynamic headroom, this makes the SX-1980 Pioneer's most powerful receiver, as well as being one of the most powerful receivers ever manufactured in the world, to date. It was also tested in the December 1978 issue of Stereo Review. Some results were:

With both channels driving 8-ohm loads at 1,000 Hz, the outputs clipped at 300 watts per channel (IHF clipping headroom equals 0.46 dB). The dynamic headroom was 0.63 dB. ... The distortion at 1,000 Hz was nearly unmeasurable at any power level. It was no more than 0.003% from 0.1 to 100 watts output, rose to 0.0045% between 200 and 290 watts, and reached its maximum of 0.008% at 300 watts, just before clipping occurred. The intermodulation distortion (IM) was about 0.03% at most power levels up to 100 watts and reached 0.045% at 300 watts.

The SX-1980 is 22 inches (560 mm) wide, 19.5 inches (500 mm) deep, and 8.25 inches (210 mm) high, and weighs 78 pounds (35 kg). The case, like the Pioneer HPM-100, has a fine-grain, walnut veneer finish. It has a pair of large die-cast aluminium heatsinks, located at the sides towards the back, in order to dissipate the immense heat that the receiver can generate. The receiver had 12 Field Effect Transistors (FETs), 11 Integrated Circuits (ICs), 130 transistors and 84 diodes. Its retail price in 1978 was US$1295. According to the CPI inflation calculator, that would equate to about US$5,450 in 2021. The SX-1980 is known for its total harmonic distortion (THD) rating of less than 0.03% at rated power, which is much less than the 1–10% commonly used today. The build quality is also higher than average. The unit compares favorably in side-by-side tests with newer large receivers. With a rated power consumption of 1400 volt-amperes or nearly 1000 watts, it would consume a fair amount of the power a standard 15-amp, 120-volt (North America) circuit can safely deliver. From the operating instructions document:

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 employ 22,000 μF 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 (80 dB) and low distortion ... The local oscillator includes Pioneer's very own quartz sampling locked APC (Automatic Phase Control). The 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.

Apart from its high output power capability, the Pioneer SX-1980 had quite advanced performance in many other important areas. The THD versus frequency response curve showed very low distortion levels over a wide range of operating conditions. Phono cartridge load selectors allowed the user to select from three input resistances (10, 50, and 100 kΩ) and four input capacitances (100, 200, 300, and 400 pF). The RIAA equalisation was accurate to within ±0.2 dB from 20 Hz to 20 kHz (tested as ±0.1 dB), and a high-accuracy performance specification such as this is not often achieved, even today.

References

Illustrations

Worked examples

Example 1 — a first encounter with Pioneer SX-1980

Start with the simplest possible case. Write down what Pioneer SX-1980 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pioneer SX-1980 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pioneer SX-1980 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pioneer SX-1980

In research: Pioneer SX-1980 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pioneer SX-1980 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pioneer SX-1980 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Pioneer Corporation products, Products introduced in 1978, Radio technology, so understanding it makes those chapters shorter.
In everyday life: Look for Pioneer SX-1980 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Pioneer SX-1980” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Pioneer SX-1980 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pioneer SX-1980 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pioneer SX-1980 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pioneer SX-1980 in simple terms?

Why does Pioneer SX-1980 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pioneer SX-1980?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pioneer SX-1980.