Luxman LX38 (1978)

Name: Luxman LX38
Brand: Luxman

The Luxman LX38 is a tube-type stereo integrated amplifier released in March 1978 at ¥198,000. It is the fourth generation of Luxman's 38 series, which began with the SQ38F in August 1973. It weighs 20.1kg, and it shows how Luxman thought about vacuum tube amplifier design at the end of the 1970s.

The output stage uses four 50CA10 tubes. The 50CA10 is a 3-pole tube with low internal resistance, run here in class AB. Luxman paired them with a newly designed output transformer that cut power loss to less than half that of the conventional OY15 type, partly by increasing wire diameter and unifying the secondary winding. The driver stage follows a Mullard-style cathode-coupled phase-inversion circuit, with 6267 tubes in the first stage and 6AQ8 triodes in the phase-inverter. The operating point of the driver circuit is variable, and it was adjusted individually at the factory to cancel output-stage distortion. The preamp section uses low-noise 12AX7 and 12AU7 tubes, with an ultra-low-noise type reserved for the first stage of the equalizer circuit.

Rated output is 30W/30W into 8Ω or 4Ω (25W into 16Ω). Total harmonic distortion is 0.1% or less at 10W (1kHz) and 0.4% or less at rated output. Frequency response is specified at 30Hz - 40kHz ±1dB (8Ω, 1W). The tone control system is the LUX NF type with switchable bending points - 150/300/600Hz on the low end and 1.5/3/6kHz on the high end - and it can be defeated entirely. The front panel also has a low-boost switch, low-cut and high-cut filters, tape monitor and dubbing facilities, and a −20dB attenuator.

Luxman eliminated speaker and impedance switching from the output circuit entirely, arguing that excess switch contact points degraded sound quality. The volume and balance controls use a multi-slider type design with minimal left/right linkage error. Film-type coupling capacitors and a simplified signal path on printed circuit boards were adopted in the name of stability. A matching wood cabinet (W-38/36) was sold separately for ¥15,000.

Documentation on the LX38 is thin beyond its specification sheet. No period reviews have surfaced in the archive, and little is recorded about its reception. What exists comes mostly from marketplace listings. Russian sellers describe its sound as "natural, honest, and soft - very powerful, unexpected after transistors and their race for power figures," and current listings note original NEC tubes testing strong. The LX38 name appears in the 38-series lineage between the SQ38F and later iterations, but production history beyond the 1978 release date and 1978-83 production window remains undocumented.

Known Specifications

Type: Tube-type stereo integrated amplifier
Output: 30W/30W (8Ω, 4Ω); 25W/25W (16Ω); 25W+25W (8Ω, both channels, 50Hz–15kHz)
Tubes: 50CA10 ×4, 6AQ8 ×2, 6267 ×2, 12AX7 ×3, 12AU7 ×1
Frequency response: 30Hz–40kHz ±1dB (8Ω, 1W)
Damping factor: 16 or more (8Ω, 1kHz)
S/N ratio: 75dB+ (phono), 95dB+ (line)
Dimensions: 440 × 162 × 343 mm
Weight: 20.1kg
Price at release: ¥198,000 (March 1978)