The Pioneer Sx-850 stands as a testament to the golden era of hi-fi audio, a vintage stereo AM/FM receiver that continues to captivate enthusiasts with its robust performance and timeless design. Introduced between 1976 and 1978, this receiver is more than just a piece of audio equipment; it’s a symbol of Pioneer’s commitment to quality and a cherished component in the collections of audiophiles worldwide. Let’s delve into what makes the Pioneer SX-850 a standout in the realm of vintage audio.
Unveiling the Pioneer SX-850: Design and Features
The SX-850 is aesthetically striking, embodying the classic silver-faced design that defined 1970s stereo equipment. Beyond its visual appeal, the receiver is engineered for superior audio fidelity. Pioneer emphasized that power output alone doesn’t guarantee musical satisfaction, highlighting the sophisticated circuitry within the SX-850 as its true strength.
This receiver delivers a continuous power output of 65 watts per channel into 8 ohms, across the full audible frequency range of 20Hz to 20kHz, with a minimal total harmonic distortion of just 0.1%. This specification underscores its ability to deliver clean and powerful sound, suitable for a wide range of musical genres and listening levels in typical home environments.
Pioneer SX-850 Vintage Stereo Receiver – Front View. A classic AM/FM receiver from the 1970s, showcasing its iconic silver faceplate and controls.
A key feature of the Pioneer SX-850 is its super-quiet phono equalizer. Designed in a 3-stage direct-coupled configuration, it ensures a wide dynamic range and precise RIAA equalization accuracy within ±0.2dB. This meticulous design is crucial for vinyl enthusiasts, promising accurate and noise-free playback from phono sources.
Further enhancing its versatility, the SX-850 includes a FET in the tone control section, along with 2-step frequency turnover switches for both Bass and Treble. This provides users with fine-grained control over the audio spectrum. Additional features such as 2-deck monitor/dubbing, 2-system speaker drive, and separable pre/main sections expand its functionality and connectivity options, making it a flexible centerpiece for any audio system.
Technical Specifications: A Closer Look
For those who appreciate the technical details, the Pioneer SX-850 boasts impressive specifications that reflect its high-quality engineering:
- Tuning Range: Covers both FM and MW bands, allowing for a wide range of radio reception.
- Power Output: 65 watts per channel into 8Ω (stereo), sufficient for driving most bookshelf and many floor-standing speakers.
- Frequency Response: Spans from 10Hz to 50kHz, indicating its capability to reproduce a broad spectrum of audio frequencies.
- Total Harmonic Distortion: A low 0.1%, ensuring minimal unwanted noise and distortion in the audio signal.
- Damping Factor: Rated at 25, contributing to good speaker control, especially in the bass frequencies.
- Input Sensitivity: Offers various input sensitivities (6.5mV for mic, 2.5mV for MM phono, 150mV for DIN and line), accommodating a range of audio sources.
- Signal to Noise Ratio: 70dB for MM phono and 90dB for line inputs, indicating quiet operation and clear signal reproduction.
- Output Options: Includes line and preamp outputs, as well as DIN connectors for versatile connectivity.
- Speaker Load Impedance: Designed to handle speaker loads down to 4Ω (minimum), providing flexibility in speaker selection.
- Semiconductor Components: Utilizes a sophisticated array of components, including FETs, ICs, transistors, and diodes, reflecting its advanced circuitry for the time.
- Dimensions and Weight: Measures 526.6 x 173 x 411.5mm and weighs 19.1kg, indicative of its substantial build quality.
These specifications collectively highlight the Pioneer SX-850 as a well-engineered receiver, built to deliver high-fidelity audio performance and provide a range of features for the discerning listener.
Sound Quality and Performance
The Pioneer SX-850 is not just about specifications; it’s about the listening experience. Users consistently praise its clean and crisp sound quality. The receiver is noted for its ability to deliver a balanced audio spectrum, with tight lows and sparkling highs, as mentioned by reviewers. The FM tuner section is also highly regarded, utilizing a dual-gate MOS FET and a 4-gang variable capacitor to enhance sensitivity and selectivity, ensuring clear and stable FM reception. The inclusion of a PLL IC in the multiplex section further improves stereo separation, crucial for an immersive listening experience.
The SX-850’s phono stage is frequently lauded for its superb performance, making it a favorite among vinyl record enthusiasts. Its ability to handle power with musicality, as emphasized in the original description, translates to a receiver that can drive speakers effectively without sacrificing sonic nuance and detail.
User Reviews and Community Insights
The enduring popularity of the Pioneer SX-850 is reflected in user reviews and community feedback. Owners often highlight its robust build quality, attractive aesthetics, and, most importantly, its exceptional sound. Many reviewers recount decades of reliable performance, with some units still going strong after minimal servicing, a testament to its durability.
Common themes in user reviews include:
- Excellent Sound Quality: Repeated praise for its clean, crisp, and balanced sound, particularly the phono stage.
- Reliability: Many users have owned their SX-850s for decades, often with minimal maintenance.
- Aesthetics: The classic silver-face design is consistently admired.
- Power and Performance: Sufficient power for most home listening environments, with the ability to drive various speakers effectively.
While some units may require servicing due to their age, particularly capacitor replacement and switch cleaning, owners often find the investment worthwhile, emphasizing that a serviced SX-850 can deliver outstanding performance that rivals or surpasses many modern receivers.
Conclusion
The Pioneer SX-850 is more than just a vintage stereo receiver; it’s a piece of audio history that continues to offer exceptional sound quality and enduring appeal. Its blend of robust power, sophisticated features, and classic design makes it a sought-after piece for vintage audio enthusiasts and anyone looking to experience the warmth and richness of classic hi-fi sound. Whether you are a vinyl collector, FM radio enthusiast, or simply an admirer of quality audio, the Pioneer SX-850 remains a worthy contender in the world of stereo receivers, proving that some audio classics truly stand the test of time.
