Luxman CL 350 (1972)
A transistor-based control amplifier released by Luxman in August 1972, featuring advanced equalizer and tone control circuits for high-fidelity audio systems.
Overview
The Luxman CL 350 is a control amplifier manufactured by Luxman and released in August 1972. It was the company's first control amplifier to use transistors, marking a shift in design philosophy. The unit supports multiple input types including phono, auxiliary, tape, and microphone, with dedicated amplifiers for each input to minimize noise and interference. It features a built-in headphone amplifier, tone controls with selectable frequency points, and high- and low-cut filters for noise reduction.
Specifications
| Frequency characteristic | 10 Hz to 50 kHz -1dB |
| Total harmonic distortion factor | 0.03% or Less (Output 1 V) |
| Output voltage Rating | 1 v; Maximum: 7 v (0.3% strain rate) |
| Output impedance Pre out | 100 Ω |
| Input sensitivity Phono1/2 | 2mV; Aux1/3 : 110 mV (Variable); Aux2, Tape1/2 : 110 mv; Mic:2.3mV |
| Input impedance Phono1 | 100 Ω, 50 Ω, 30k Ω switching type; Phono2 : 50k Ω; Aux1/3 : 50k Ω; Aux2 : 100k Ω; Mic : 50k Ω; Tape1/2 : 130k Ω |
| Signal-to-noise ratio Phono | 63 dB or more; Aux, Tape : 80 dB or more; Mic : 59 dB or more |
| Input voltage resistance Phono | 300 mV or more |
| Equalizer RIAA | 30 Hz to 15 kHz ± 0.3 dB |
| Tone control | LUX System NF Type with Bending Point Switching; Low-pass curve point : 150 Hz, 300 Hz, 600 Hz; High-frequency bending point : 1.5 kHz, 3 kHz, 6 kHz |
| Low-cut filter | 25 Hz, 60 Hz |
| High-cut filter | 7 kHz, 12 kHz |
| Low frequency trimmer | ± 0.6 dB at 250 Hz |
| Attenuator | -15dB |
| Headphone out | 80mW |
| Semiconductor used | Silicon transistor : 49 units; Diode : 8 pcs |
| External dimensions | Width 476x Height 182x Depth 244 mm |
| Weight | 8.8kg |
Design
The CL 350 uses transistors throughout and features a 3-stage direct-coupled equalizer circuit combining PNP and NPN types, with the third stage operating in push-pull for improved linearity and power efficiency. Each input has its own amplifier, and selection occurs only on the output side, reducing noise from switching and shielding. The LUX System NF tone control allows 3-step switching of low and high-frequency bending points and includes a defeat switch. High- and low-cut filters offer two cutoff frequencies to reduce noise without affecting program content. The unit uses ultra-low noise PNP silicon transistors to maintain a low noise floor. A built-in low-frequency trimmer adjusts the 150–300 Hz range and is placed after the equalizer to minimize impact on recorded output. The headphone amplifier uses a fully direct-coupled complementary circuit with an output capacitor. Phono1 includes impedance switching, while Phono2 supports an MC step-up transformer. Aux1 and Aux3 include level controls. The chassis was available in Shiraki and Rosewood finishes, matching the M150 power amplifier.
Market
The Luxman CL 350 was originally priced at ¥79,000 at its release in August 1972.
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