GRUNDIG RR 1040 (1979)

 

Introduced in 1979 the RR 1040 by Grundig in addition to a large, easily readable scale and an excellent signal strength meter adds a digital frequency display. Thus the Grundig RR 1040 makes radio station searching a real pleasure. Especially on shortwave, the directly readable reception frequency helps to find the desired station. In terms of ease of use, this Grundig model was superior to its Far Eastern competitor, as the FM station buttons allow for lightning-fast selection between... read more.

ONKYO Liverpool Q-1 (1990) | A Distinctive Hi-Fi System with Top-Mounted Tweeter

The Onkyo Liverpool Q-1 was part of the Liverpool Collection, a distinctive hi-fi system created for enthusiasts who valued both sound and aesthetic design. Combining the Q-1 speakers with the R-100 receiver, C-100 CD player and optional K-100 cassette deck, the system offered a complete compact audio setup with a particularly unusual speaker design.

Onkyo Liverpool Q-1 System – Main Specification

Q-1 Speaker System

Type: 2-way bass reflex

Impedance: 6Ω

Maximum input: 160 W

Output sound pressure level: 89 dB/W/m

Frequency response: 37 Hz–45 kHz

Crossover frequency: 2.5 kHz

Woofer: 16 cm Pure Cross Carbon

Tweeter: 2.5 cm Plasma Carbonized Titanium Dome

External dimensions: 230 × 456 × 265 mm (W × H × D)

Weight: 9 kg

R-100 FM/AM Receiver

Power output: 2 × 60 W RMS (DIN)

Dynamic power: 2 × 120 W

Tuner: FM/AM

Presets: 30 FM/AM station presets

Inputs: Phono MM, CD, Tape, Aux (Video)

Feature: Source Direct

Remote control: Full remote operation

Motorized controls: Volume and tone controls

Additional functions: Sleep timer and automatic station search

Headphone connection

Display: LCD

Dimensions: 435 × 89 × 354 mm

Finish: Titanium-colored housing

C-100 CD Player

Oversampling: 8×

D/A conversion: Two separate D/A converters

Signal isolation: Opto-coupling

Playback modes: Normal, Shuffle, Memory and Memory Shuffle

Programmable tracks: 20

Tray: Vibration- and shock-free design

Remote control

Dimensions: 435 × 89 × 340 mm

Finish: Titanium-colored cabinet

K-100 Auto-Reverse Dual Cassette Deck

Configuration: Two cassette decks

Operation: Normal, continuous playback and double-speed copying

Noise reduction: Dolby B/C

Tape technology: HX Pro

Function: Auto-Space automatic pause

Motors: Two DC motors plus one servo motor for the capstan drive

Dimensions: 435 × 118 × 344 mm

Finish: Titanium-colored housing

Original sale price in Japan:

R-100 tuner amplifier: ¥60,000

C-100 CD player: ¥45,000

Q-1 speakers: ¥35,000 × 2

K-100 cassette deck: ¥55,000

CB-100H system rack: ¥30,000

AS-Q1 speaker stands: ¥25,000 per set of two

Extra component: ML-500 CD/CDV/LD player ¥139,000

Onkyo Liverpool Q-1 Technology and Design. The Top-Mounted Tweeter: The most distinctive feature of the Q-1 is its top-mounted tweeter. Instead of mounting the tweeter conventionally on the front baffle, Onkyo positioned it independently on top of the cabinet. According to the original material, this arrangement was developed to eliminate baffle-plate reflections that could subtly affect reproduction, particularly in the tweeter range. The design also aimed to improve directivity and create greater depth in the sound image. Onkyo described the resulting presentation as a spacious and transparent soundscape, with a three-dimensional character extending beyond the conventional left-to-right stereo image. Carbon-Based Driver Technology. The Q-1 uses specialized driver materials for both its woofer and tweeter. The 16 cm woofer employs Pure Cross Carbon, while the 2.5 cm tweeter uses a Plasma Carbonized Titanium Dome. Together with the 2-way bass-reflex cabinet and 2.5 kHz crossover, these components form the core of the Q-1's loudspeaker design.

R-100 Receiver. The R-100 was designed as the system's control center. Despite its relatively compact format, it provided connections for Phono MM, CD, Tape and Aux (Video), together with Source Direct. Its remote control operated all functions, including tone controls and volume through a motorized potentiometer. The receiver also included automatic station search, 30 FM/AM presets, a sleep timer, headphone connection and an LCD display.

C-100 CD Player. The C-100 combines digital playback features with flexible programming. Its 8× oversampling system, two separate D/A converters and opto-coupling were among its principal technical features. Four playback modes were provided, including Shuffle and Memory Shuffle, while up to 20 tracks could be freely programmed.

K-100 Dual Cassette Deck. The K-100 provides two cassette transports in one cabinet. Its dual-deck arrangement allowed normal playback, continuous playback and double-speed tape copying. Dolby B/C, HX Pro and Auto-Space were included, while two DC motors and a servo motor for the capstan drive were specified for precise operation.

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B-I-C T-4M (1979) | 2-Speed 3-Head

The B-I-C T-4M was no ordinary cassette deck. With two tape speeds, full metal-tape capability, and B-I-C's exclusive Broadband Electronics, it pushed the compact cassette format remarkably close to open-reel performance.

B-I-C T-4M Main Specifications

Tape speeds: 4.75 cm/s and 9.50 cm/s

Frequency response at 4.75 cm/s: 20 Hz–21 kHz ±3 dB

Frequency response at 9.50 cm/s: 20 Hz–23 kHz ±3 dB

Wow and flutter at 4.75 cm/s: 0.05% WRMS / 0.09% DIN

Wow and flutter at 9.50 cm/s: 0.03% WRMS / 0.07% DIN

Total harmonic distortion: 1.3% at 4.75 cm/s

Fast-forward/rewind: approximately 48 seconds with a C-60 cassette

Level meters: Peak-indicating LED bar graph, –36 to +9 dB

Drive system: Two-speed tachometer-feedback DC servo motor

Transport: Dual-capstan design

Spooling: DC spooling motor

Dimensions (W/H/D): 440x164x257mm

Weight: 8,4kg

Broadband Electronics was the heart of the T-4M's design. B-I-C developed this circuitry to take advantage of the increased performance available from higher tape speed while maintaining an unusually wide response at the standard 4.75 cm/s cassette speed. At 4.75 cm/s, the T-4M was specified to reach 20 Hz to 21 kHz ±3 dB. Increase the tape speed to 9.50 cm/s and the specification extended to 20 Hz to 23 kHz ±3 dB. That second speed was the real attraction. Running cassette tape at 9.50 cm/s offered substantially more bandwidth and lower wow and flutter, allowing B-I-C to position the T-4M as a cassette deck capable of challenging open-reel machines. Metal tape capability added another advantage. Combined with the higher tape speed and Broadband Electronics, it gave the T-4M the technical foundation for its unusually ambitious performance claims. The transport was equally important. A dual-capstan mechanism and tachometer-feedback DC servo motor were employed to maintain precise tape movement, while a separate DC spooling motor handled fast winding operations. Dolby NR and Signal-to-Noise Performance. Noise reduction was an important part of the T-4M's specification. At 4.75 cm/s, the quoted signal-to-noise ratio was 57 dB, increasing to 65 dB with Dolby NR. At 9.50 cm/s, the figure rose to 61 dB, while B-I-C specified 68 dB with Dolby NR and metal tape. For a cassette deck of its era, these figures demonstrate just how seriously B-I-C approached high-performance recording. The 9.50 cm/s Advantage. Why the higher speed mattered? Tape speed has a direct influence on cassette performance. Increasing the speed from 4.75 cm/s to 9.50 cm/s allowed the T-4M to achieve its widest specified frequency response while also reducing measured wow and flutter. At 9.50 cm/s, wow and flutter was rated at just 0.03% WRMS, compared with 0.05% at the standard speed. The same time you might ask yourself about compatibility with other devices. B-I-C solved this problem by adding a 2-speed car audio cassette deck for all your double speed recordings.

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STAX CDP QUATTRO (1986) | High Resolution QUATTRO

The STAX CDP QUATTRO was Stax’s first CD player, introduced in 1986 at a time when digital audio was still a relatively new technology. Combining a Yamaha-made CD mechanism with Stax-developed digital and analog circuitry, it took an unusually uncompromising approach to mechanical isolation, noise reduction, and signal processing.

STAX CDP QUATTRO – Specifications

Model: STAX CDP

Release: 1986

Digital processing: 16-bit, 4x oversampling digital filter

Oversampling frequency: 176.4 kHz

D/A conversion: Separate DACs for left and right channels

Frequency response, Direct Out: 0.7 Hz–20 kHz, ±0.5 dB

Frequency response, Filtered Out: 0.4 Hz–18 kHz, ±0.5 dB

Signal-to-noise ratio: 104 dB or higher

Dynamic range: 96 dB or higher

Total harmonic distortion: 0.002% or less at 0 dB, 1 kHz

Crosstalk: -100 dB or less, 5 Hz–16 kHz

Dimensions: 435 × 165 × 290 mm

Weight: 8.0 kg

Original sale price in Japan: ¥270,000

Stax’s Proprietary Circuit and Chassis Design. The two-tier chassis is one of the most distinctive aspects of the STAX CDP QUATTRO. Rather than simply placing one component on top of another, Stax built the player around a sturdy wooden board supported by tall aluminum pillars. The CD mechanism sits above the board, while the electronic section is suspended underneath. Mechanical and electrical separation was taken particularly seriously. The mechanism section and electronics section were separated, including their power arrangements, to reduce unwanted mechanical and electrical interaction. The electronic circuitry was housed in a wooden chassis designed to provide protection from electromagnetic interference. A Digital Filter Designed to Minimize Analog Filtering. The 4x oversampling system was central to Stax’s approach to digital audio. A CD uses a 44.1 kHz sampling frequency. During digital-to-analog conversion, unwanted higher-frequency components can appear alongside the audio signal and normally have to be removed with an analog filter. Stax instead used a 16-bit, 4x oversampling digital filter, raising the sampling frequency to 176.4 kHz. This pushed unwanted components much farther away from the audible band. The result was that a relatively low-order analog filter could be used rather than a more complex high-order design. Discrete FET Analog Amplifier. The analog amplifier section used an all-FET discrete amplifier designed for high-speed response and good linearity. Stax also paid considerable attention to the deglitch circuit following the D/A converter. Instead of relying on operational amplifiers, the circuit used discrete components and a balanced-charge MOS FET arrangement intended to minimize switching-related spike noise. Separate Left and Right DACs. The dual-DAC configuration used independent ladder-type converters for the left and right channels. This arrangement was designed to maintain accurate channel separation and eliminate phase differences between the two channels. The specification lists an impressive 0° L/R phase difference from 5 Hz to 20 kHz, together with crosstalk of -100 dB or less. Direct and Filtered Outputs. Two output approaches were provided. The Direct Out was intended to take advantage of the player’s digital processing and allow the signal to be output without a conventional analog filter. For applications such as tape recording, where unwanted high-frequency components could potentially produce beat frequencies, Stax also provided a Filtered Out using a gently tuned third-order Bessel analog filter. Absolute Phase Switching. A rear-panel phase switch allowed the absolute phase to be inverted by changing the digital data. This was an unusual feature and reflected Stax’s attention to subtle aspects of signal reproduction.

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Sansui AU-X1111 MOS VINTAGE (1988) | The Double Eleven Integrated Amplifier

The Sansui AU-X1111 MOS VINTAGE is the final 1988 model in Sansui's legendary series of “The 1” amplifiers, following the AU-X1 (1979), AU-X11 (1982), and AU-X111 MOS VINTAGE (1985). Known as “Double Eleven,” this flagship integrated amplifier combines Sansui's balanced circuit philosophy, MOS FET power devices, and exceptionally robust construction in a 35.1 kg design aimed squarely at serious music reproduction.

Sansui AU-X1111 MOS VINTAGE Specifications

Year: 1988

Power output: 110 W + 110 W into 8 ohms, both channels driven, 20 Hz–20 kHz

Power output: 150 W + 150 W into 6 ohms

Total harmonic distortion: No more than 0.008% at rated output

Intermodulation distortion: Less than 0.008%

Slew rate: 150 V/µs at 8 ohms

Rise time: 0.5 µs

Damping factor: 200 at 8 ohms

Frequency response: DC–300,000 Hz from CD input

Signal-to-noise ratio: 88 dB, PHONO MM

Signal-to-noise ratio: 110 dB, CD/TUNER/LINE and TAPE/DAT

Subsonic filter: 3 dB at 16 Hz, 6 dB/octave

Muting: 20 dB

Presence control: +2 dB at 200 Hz; +6 dB at 10 kHz with volume at -30 dB

Power supply: 230 V, 50/60 Hz

Nominal consumption: 350 W / 560 VA

Maximum power consumption: 820 W

Dimensions: 470 × 178 × 486 mm

Net weight: 35.1 kg

Original sale price in Germany: 6.500 DM

MOS FET power devices are at the heart of the AU-X1111 MOS VINTAGE. Sansui selected these devices as part of its continuing pursuit of high-fidelity amplification and used them within an amplifier architecture developed through years of circuit refinement. The AU-X1111 represents the culmination of a design philosophy that Sansui had been developing since its wide-range DC amplifier of 1976. Balanced transmission and amplification became a defining element of Sansui's approach, particularly following the introduction of the B-2301 in 1983. The company combined this philosophy with a twin-mono construction intended to optimize the amplifier's essential structural requirements. Over the years, Sansui developed a series of distinctive technologies, including the diamond differential circuit, non-magnetic flux-free design, Super Feedforward, ground floating circuit, and twin-diamond balanced drive circuit. The AU-X1111 MOS VINTAGE brings this accumulated experience together in a single integrated amplifier. Its unusually wide DC–300 kHz frequency response, 150 V/µs slew rate, and 0.008% maximum THD reflect the engineering priorities of Sansui's flagship designs of the period. Why the AU-X1111 Is Special? The “1111” designation was deliberate. Sansui presented “1111 = Double Eleven” as its answer to the pursuit of sound quality and positioned the AU-X1111 as a new expression of its amplifier philosophy. Rather than treating the amplifier simply as a collection of technical specifications, Sansui emphasized the relationship between technology and musical expression. The company described the AU-X1111 as the result of continuous refinement in circuits, mechanisms, and components, with quality parts developed through the history of its amplifier designs.

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AIWA DR-1, DR-2 (1985) | Computer Love

The DR-1 and DR-2 from Aiwa employs a proprietary digital signal waveform processing circuit. These data recorders were designed to meet the demands of the new digital age. The digital signal waveform processing circuit drastically reduces errors. Aiwa's advanced technology has finally addressed the loading errors that have plagued us until now. The adoption of a unique digital signal waveform processing circuit has dramatically reduced errors. Furthermore, features such as completely automatic level adjustment have dramatically improved reliability and ease of use. It's also perfectly compatible with PCs. Digital signal waveform processing. Digital signal waveform processing circuit: Even distorted analog signals are corrected into digital signal waveforms that are easy for computers to interpret. This reduces errors due to dropouts and phase shifts, achieving a level of reliability not possible with conventional data recorders.

Specifications DR-1

Achieves high-speed processing via RS-232C, far exceeding traditional floppy disk transfer rates. | Includes a multi-functional, advanced TOS (for PC-8801 series), enabling recording equivalent to approximately 10 floppy disks. | <Graphics> Fast screen saving/loading (55 seconds), and high-speed file searching are also possible. Auto-rec mute mechanism | Phase switching switch | Access indicator Tape speed: 4.75cm/sec | Supported transfer speeds: CMT mode 600-2,400bps, RS-232C mode 600-9,600bps | Compatible tapes: CMT mode normal tape (TYPE1), RS-232C mode metal tape | Maximum external dimensions: Width 175 x Height 112 x Depth 260mm | Weight: 2.5kg | Power supply: AC100V (50/60Hz) | Accessories: RS-2320 dedicated cable, TOS tape for PC-8801 series | original sale price in Japan ¥28,500

Specifications DR-2

Achieves double-speed loading. (MSX1200 baud tape) | Includes a sub-out terminal that processes backup tapes with digital signal waveforms. | Convenient MOTOR button for saving/loading | Phase switching switch | Tape speed: 4.75/9.5 cm/sec | Supported transfer speed: 600-2,400 bps | Tape type: Normal tape (TYPE 1) | Maximum external dimensions: Width 166 x Height 128 x Depth 146 mm | Weight: 1.2 kg | Power supply: AC100V (50/60Hz) | Original sale price in Japan ¥12,800

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PHILIPS LHH-800R (1995) | Reference CD Player

Built for Natural, Precise Music Reproduction the Philips LHH-800R represents an uncompromising approach to CD playback, designed to extract the musical information recorded on the disc while pursuing a natural, highly responsive sound. Developed as a luxurious refinement of the technology used in Philips' Reference Series, the LHH-800R combines advanced digital circuitry with carefully engineered analog stages.

Philips LHH-800R Main Specifications

Frequency response: 20–20,000 Hz ±0.5 dB

Dynamic range: 96 dB

Signal-to-noise ratio: 100 dB or more

Channel separation: 96 dB or more at 1 kHz

Harmonic distortion: 0.005% or less at 1 kHz

Dimensions: 474.5 × 143 × 359 mm (W × H × D)

Weight: approximately 18.5 kg

Accessories: RC800R LHH remote control

Original sale price in Japan: 450.000 Yen

A newly developed discrete amplifier is one of the defining elements of the LHH-800R. Philips removed the operational amplifier from the DAC7 I/V stage and replaced it with a wideband discrete amplifier designed for very high speed. The amplifier is specified with a 200 V/µs slew rate, allowing the circuit to respond rapidly to musical transients while maintaining a wide dynamic range. The design goal was not simply higher speed. Philips aimed to combine fast response with what the company described as a warm and natural sound quality. Philips DAC7: A Direct, Music-Focused Approach. The DAC7 is the heart of the digital-to-analog section. Philips used its proprietary Bitstream D/A converter in a deliberately simple single differential configuration. Rather than surrounding the DAC with a complicated circuit, the design concentrates on bringing out its characteristics directly. The stated result is a direct presentation intended to preserve the energy and dynamism of the music. The following differential amplifier also avoids conventional op-amps. Instead, Philips uses a discrete, low-negative-feedback configuration designed to provide excellent phase characteristics, wide dynamic range, high speed, and strong instantaneous current capability. The LHH-800R uses a fully balanced four-channel output arrangement, with the positive and negative phases kept aligned without relying on transformers or inverting amplifiers. This approach was intended to maximize the advantages of balanced transmission while achieving extremely linear operation. The balanced outputs also provide compatibility with BTL drive amplifiers, giving the LHH800R additional flexibility for advanced systems. Separate Power Supplies for Digital and Analog Sections. Power supply design receives considerable attention. The LHH800R employs two independent power transformers, with separate transformers assigned to the analog and digital sections. Philips also describes independent power-supply arrangements for individual stages, including the display section, in an effort to minimize interference caused by the power supply. The analog and DAC sections therefore receive dedicated power treatment rather than relying on a single shared transformer arrangement. Simple Analog Output Filtering. The analog low-pass filter uses a simple third-order CR configuration. Philips emphasizes its phase characteristics and the intention to minimize its influence on the audio signal. This reflects the overall philosophy of the LHH800R: use straightforward circuit arrangements where possible while concentrating engineering effort on the sections that directly influence signal conversion and transmission. High-End Construction and Styling. The LHH-800R is built as a substantial high-end component. At approximately 18.5 kg, its construction reflects the ambitious position of the model within Philips' CD player range. The chassis incorporates aluminum die-cast construction, while the front panel combines wood and a gold-like material in a distinctive design influenced by European aesthetic. The unit also uses fully integrated RCA pin jacks designed for durability, together with a so called Nafuron material for the connections. What Makes the Philips LHH-800R Special? The LHH-800R was created as a refined development of Philips' Reference Series philosophy: a straightforward concept intended to bring digital and analog technology together as naturally as possible. Its most distinctive technical choices are the DAC7 Bitstream converter, discrete I/V conversion, fully balanced four-channel output, separate digital and analog transformers, and extensive attention to power-supply isolation. Rather than relying on specifications alone, Philips positioned the LHH-800R around the pursuit of natural sound, accurate timing, wide dynamics, and faithful reproduction of the musical energy contained on the CD.

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TEAC CR-H248 (2010) | 1001 Hi-Fi Webpage Update

Since its foundation in 1953, TEAC has made great contributions to both end-user and specialist industrial fields, being involved in consumer and professional audio, computer peripherals, and the medical and aviation industries. Since the introduction of the original TEAC Reference 500 Series in the mid-1990s, the concept of TEAC's mini component system has remained. Most of the features required for a complete contemporary full-size audio system were included in the CR-H248, introduced in 2010. Finished in sleek jet black, this mini stereo system, a rightful heir to ... Discover More

TEAC Reference 500 (1997) | The H-Series Mini System That Put Separates in a Compact Format

The TEAC Reference 500 was far more than an ordinary mini system—it was TEAC’s attempt to bring genuine separates-class engineering into a compact, modular package. With substantial aluminium front panels, independent power supplies and a surprisingly sophisticated component lineup, the Reference 500 remains an intriguing piece of vintage audio history.

TEAC Reference 500 – Main Specifications

System concept: H-Series modular mini system

Core components: R-H500 cassette deck, PD-H500 CD player, T-H500 stereo tuner and A-H500 stereo amplifier

Optional components: AG-H500 stereo receiver, AV-H500 Pro-Logic Surround Amplifier, VRDS-9 CD player, PD-H503 multi-CD player, RW-H500 CD recorder and MD-H500i MiniDisc recorder, DV-H500 DVD player

Construction: 10 mm thick aluminium front panels

Chassis: High-rigidity construction

Connections: Gold-plated RCA jacks

Remote control: Full-function infrared control system

Amplifier design: Separate left/right circuits

Power supply: Fully shielded toroidal transformer and upgraded 4-ohm power supply

CD input: Direct CD switching for a shortened signal path

Architecture: Modular components with individual power supplies

Expansion: Designed to accommodate future components and upgrades

The H-Series Concept: Miniature Separates, Not a Typical Mini System

The H-Series philosophy was simple: reduce the physical size without reducing the quality of the individual components. Rather than building everything into one chassis, TEAC divided the system into separate amplifier, CD player, tuner and cassette deck units. Each component had its own enclosure and power supply, making the Reference 500 much closer in spirit to a traditional separates system than a conventional all-in-one mini system. The construction was equally serious. Every component used a substantial 10 mm aluminium front panel, giving the system a distinctive, high-end appearance while contributing to rigidity and durability. The high-rigidity chassis construction was another indication that TEAC was targeting enthusiasts rather than casual mini-system buyers. A System Designed to Grow. Modularity was one of the Reference 500’s strongest features. Owners could start with the basic four-component system and expand it as new technologies became available. The Reference 500 family eventually included considerably more than the original amplifier, tuner, CD player and cassette deck. Additional components included a Pro-Logic surround amplifier, multi-CD player, CD recorder, MiniDisc recorder and other system components. The A-H500 Amplifier: Simplicity With Serious Engineering. At the heart of the system was the A-H500 stereo amplifier. Its design incorporated separate left and right circuits, a fully shielded toroidal transformer and an improved power supply intended to handle 4-ohm speaker loads. TEAC also kept the signal path deliberately straightforward. The CD Direct function was particularly interesting. When selected, the CD signal could bypass unnecessary circuitry, providing a shorter and cleaner path between the source and amplification stage. For vintage audio enthusiasts, this is an important detail because it reflects an engineering philosophy that was common in serious hi-fi equipment: eliminate unnecessary processing rather than simply adding features. Intelligent System Control. The Reference 500 also attempted something surprisingly advanced for its era: system-level automation. The components were designed to communicate intelligently through the control system. For example, pressing PLAY on the CD player while listening to FM could automatically switch the amplifier to the CD input and begin playback. Similar interactions were available between the tuner and cassette deck. The system could even automatically activate previously configured RDS functions when traffic information was received. Today, this behaviour seems ordinary. In the context of a vintage component system, however, it was an impressive attempt to make separate hi-fi components operate as a unified system. 

The Hidden Story: Who Actually Built the Reference 500?

Here is where the Reference 500 story gets particularly interesting. Although these components carried the TEAC name, the H-Series units were actually manufactured in Korea by ANAM. ANAM was an important OEM manufacturer and produced equipment not only for its own brand (including the above shown Teac components) but also for other companies. The same or closely related hardware can therefore be found under different brand names, including Akai and Universum, the latter being associated with Quelle in Germany.

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PIONEER SX-3500 (1980) | 20 Watts of Classic Pioneer Engineering

The Pioneer SX-3500 from 1980 was a compact vintage stereo receiver that combines a 20-watt-per-channel power amplifier with a highly sensitive FM/AM tuner and a carefully engineered phono section. Introduced as a practical alternative to oversized, high-power receivers, the SX-3500 focuses on clean performance, useful headroom, and sophisticated circuitry without unnecessary complexity.

Pioneer SX-3500 Main Specifications

Continuous power output: 20 watts per channel, both channels driven

Load impedance: 8 ohms

Frequency response: 20Hz–20kHz

Total harmonic distortion: No more than 0.05%

Dimensions: 17 11/16 × 5 5/8 × 12 7/16 inches

Weight: 16 lb 12 oz

Original sale price: 225 USD

The specifications tell only part of the story. The SX-3500's real appeal lies in how Pioneer combined several advanced circuit concepts into a relatively modestly powered receiver. Pioneer SX-3500 Circuit Design and Proprietary Technology. Bootstrapped Power Amplifier. Pioneer used a time-tested amplifier topology rather than chasing extremely high output figures. The SX-3500's power amplifier employs a current-mirror-loaded differential input, followed by a bootstrapped predriver and a fully complementary push-pull output stage. Each channel uses two specially selected power transistors in the output stage. With 20 watts per channel available continuously into 8 ohms and distortion limited to 0.05%, Pioneer considered this enough power for a typical listening room while retaining useful reserve for musical peaks. The brochure makes an important point about amplifier power: average musical levels require surprisingly little power, while short-lived peaks can demand considerably more. The SX-3500 was designed around this principle rather than simply competing on headline wattage. FLUROSCAN™ Power Meters. The blue FLUROSCAN™ bar-graph meters provide a visual indication of moment-to-moment amplifier output. Sensitive FM Front End. Pioneer's FM tuner begins with a carefully designed front end using a junction-type FET RF amplifier, transistor mixer and three-gang variable capacitor. The result is an FM usable sensitivity of 11.2dBf (2.0µV) in mono, a respectable figure for a receiver designed for the mainstream hi-fi market. Pioneer IC IF Section. The intermediate-frequency section uses a Pioneer-exclusive IC together with two two-element ceramic filters. The filters help reject noise, distortion and interference, while the transistor IF amplifier provides additional signal gain before the FM signal reaches the stereo demodulator. PLL Stereo Multiplex. A PLL multiplex circuit provides stable stereo decoding while helping maintain wide channel separation and low distortion. Pioneer also used an active low-pass filter to remove the pilot-signal components after they had served their purpose in separating the left and right channels. Low-Noise Phono Equalizer. The phono stage was given serious attention, rather than being treated as an afterthought. Pioneer's discrete two-transistor phono equalizer provides a specified 76dB signal-to-noise ratio. RIAA equalization is specified within ±0.3dB over 30Hz–15kHz, making the phono section an important part of the SX-3500's overall design. Power NFB Tone Control. Bass and treble control are integrated into the power amplifier's negative-feedback loop. Pioneer called this arrangement the Power NFB circuit. Rather than relying on a more elaborate separate tone-control architecture, the design was intended to provide an acoustically flat response while allowing bass and treble emphasis or attenuation when required by the listening environment.

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TEAC AL-700 (1976) | Esoteric Series

The TEAC AL-700 Elcaset Deck was introduced in 1976 as TEAC's first—and only—Elcaset deck. Developed around the ambitious "Open reel sound on cassette" concept, it combined 6.3 mm-wide tape, high tape speed, and sophisticated open-reel-derived mechanics in a cassette format.

TEAC AL-700 Specifications

Model: TEAC AL-700 Elcaset Deck

Release: 1976

Track format: 4-track, 2-channel stereo

Head configuration: 3-head — erase, record, playback

Tape: Elcaset LC-60 / LC-90, Type I, Type II, Type III

Tape speed: 9.5 cm/s

Capstan motor: FG servo DC motor

Reel motors: Coreless DC motors ×2

Wow & flutter: 0.04% WRMS

Frequency response: 25 Hz–20 kHz ±3 dB, Type I; 25 Hz–22 kHz ±3 dB, Type II/III

Signal-to-noise ratio: 59 dB Type I; 62 dB Type II/III

Total distortion: 0.8% Type II

Fast rewind: Within 70 seconds with LC-60 tape

Inputs: Microphone and line, with independent level controls

Outputs: Line and headphone

Noise reduction: Dolby B, with external dbx capability

Power consumption: 37 W

Dimensions: 440 × 230 × 310 mm

Weight: 18 kg

Original sale price in Germany: 2.900 DM (dbx unit: 1.200 DM)

The Elcaset Concept

Elcaset was designed to bring open-reel performance to a cassette. The format was jointly developed by Sony, TEAC, and Technics and used 6.3 mm-wide tape—the same width used by open-reel machines—inside a much larger A-6-sized cassette. With a tape speed of 9.5 cm/s, the format offered considerably more tape area for recording than a conventional cassette. The result was an ambitious attempt to combine the convenience of a cassette with the sound quality associated with open-reel tape. A major difference was the outer tape guidance system. Instead of relying entirely on the precision of the cassette shell, the AL-700 pulled the tape out of the cassette and controlled it with the deck's own transport mechanism. This approach allowed TEAC to use sophisticated mechanisms such as a dual-capstan transport and three-head arrangement. TEAC's Open-Reel Technology in an Elcaset. Its three-motor drive system used an FG servo DC motor for the capstan and two coreless DC reel motors, directly reflecting TEAC's experience with three-motor open-reel machines. Twin-Belt Closed-Loop Dual Capstan. The twin-belt system was one of the AL-700's most distinctive mechanical features. Its closed-loop dual-capstan transport used two sets of capstans and pinch rollers to grip the tape and maintain controlled tension. The slight difference in capstan speed helped suppress tape movement and flutter caused by external disturbances. However, excessive speed differences could produce excessive tension, which was particularly undesirable with relatively thin Elcaset tape. TEAC therefore added a wide auxiliary belt directly to the outer flywheel. This belt acted almost like a mechanical servo, helping maintain soft and consistent tape tension while also reducing stress on the main drive belt and flywheel. High-Precision Fixed Head. TEAC also paid unusual attention to head mounting accuracy. The AL-700 used a fixed-head system derived from TEAC's in-vehicle data recorder technology. A precision die-cast structure and central locating pin determined the head's height, tangency, and tilt. Azimuth could then be adjusted with a single screw, allowing the head to pivot around the central reference point without changing its height. The result was a considerably more precise head-mounting system than the conventional three-point adjustment arrangement. Automatic Self-Aligning Pinch Roller. The pinch roller was another example of TEAC's data-recorder engineering. Several metal balls surrounding the roller shaft allowed considerably more movement than a conventional pinch roller. This gave the roller the ability to compensate for a tilted shaft or uneven rubber wear while maintaining even pressure against the capstan. Magnefloat Capstan. TEAC's Magnefloat system addressed unwanted capstan shaft movement. Magnets positioned near the flywheel and bearing used magnetic repulsion to keep the capstan shaft pressed against a defined point. Unlike a spring-loaded mechanical arrangement, the system produced very little mechanical noise and friction. It also avoided changes in clamping force caused by temperature variations and was designed for long-term durability. Three-Head Recording and Dolby Noise Reduction. The AL-700 used a true three-head configuration, with separate erase, record, and playback heads. The record and playback heads were made from high-hardness permalloy, while the erase head used ferrite. The deck supported Type I, Type II, and Type III Elcaset tapes, with automatic bias and equalization selection through detection holes in the cassette shell. Dolby noise reduction could also be selected automatically through the cassette's detection tab. The deck additionally incorporated an MPX filter to prevent problems caused by the 19 kHz FM stereo pilot signal during radio recording. For users wanting even greater noise reduction, TEAC provided a dedicated connection for the separately sold dbx RX-10 unit. Recording and Control Features. The AL-700 was far more sophisticated than a simple playback deck. Its microphone and line inputs had independent level controls, allowing microphone mixing during recording. A centrally positioned REC MUTE button made it possible to create silent sections while recording, while the large VU meters displayed average input level and independent peak indicators helped monitor momentary overloads. The transport was operated through soft-touch microswitches and logic circuitry. Additional functions included timer operation, memory auto-stop/auto-play, output volume control, mono/stereo switching linked to the microphone input, and a Dolby copy function. The Elcaset format itself provided automatic detection for tape type and Dolby selection, allowing the AL-700 to configure important recording and playback parameters without manual intervention.

External Accessories

The AL-700 could be expanded with dedicated accessories. TEAC offered the RX-10 dbx unit and RC-90 remote control as separately sold options. TEAC RX-10 dbx unit: ¥78,000 | TEAC RC-90 remote control: ¥10,500

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