Kenwood L 07M II (c. 1978–1980)
A high-speed DC monaural power amplifier with extreme bandwidth and ultra-low distortion, built for precision audio reproduction.
Overview
The TRIO L-07MII, sold as Kenwood L-07MII in international markets, is a monoblock DC power amplifier introduced around 1978. Designed for minimal signal path and maximum stability, it delivers 150 watts into 8 ohms with exceptionally low distortion across an extraordinary frequency range. Built with advanced engineering for its time, it was updated from the L-07M to feature a dramatically extended frequency response up to 600 kHz and improved transient performance. It was succeeded by the L-08M around 1980.
Specifications
| Rated Output (10 Hz to 100 kHz) | 150W (8 Ω) |
| Total harmonic distortion factor at rated output 8 Ω, 10 Hz to 100 kHz | 0.08% |
| Total harmonic distortion factor at rated output 8 Ω, 20 Hz to 20 kHz | 0.007% |
| Total harmonic distortion factor at rated output 8 Ω / 4 Ω, 1 kHz | 0.003%/0.0035% |
| Total harmonic distortion factor at 1/10 rated output 20 Hz to 20 kHz | 0.008% |
| Frequency characteristic | DC ~ 600 kHz +0 dB -3dB |
| Cross modulation distortion factor (60Hz:7kHz=4:1) 8 Ω at rated output | 0.003% |
| Cross modulation distortion factor (60Hz:7kHz=4:1) 8 Ω at 1/10 rated output | 0.002% |
| Output bandwidth | 10 Hz to 100 kHz (IHF Distortion Factor 0.08%) |
| Signal-to-noise ratio (IHF-A) | 120dB |
| Input Sensitivity / Impedance | 1.0V/50k Ω |
| Damping factor Output terminal DC ~ 26kHz 8 Ω / DC ~ 65kHz 8 Ω | 150 / 100 |
| Damping factor 1m Cord Tip DC ~ 20kHz 8 Ω / DC ~ 40kHz 8 Ω | 120 / 100 |
| Transient response Rise Time | 0.55 μs (+1V to -1V, +20V to -20V, +40V to -40V) |
| Transient response Slew Rate | +170 V/μs, -170 V/μs |
| Rated power consumption | 190W |
| Power | 100 V, 50Hz/60Hz |
| Power outlet Power Switch Non-Interlocked | 1 Piece / 300W |
| External dimensions | Width 200 x Height 155 x Depth 390 mm |
| Weight | 13kg |
Design
The L-07MII uses a direct-coupled DC amplifier design with a minimal signal path from input to output. The voltage amplification stage employs a 3-stage differential front-end with dual FETs for low temperature drift, while the current amplification uses a two-stage Darlington triple push-pull circuit with EBT (Emitter Ballast Transistor) technology—integrating 300 low-power transistors with emitter resistors into a single chip for stable, high-power output. The power supply is isolated from the signal path and features a large transformer and dual 18,000 μF capacitors. All stages before the drive stage operate in Class A, powered by a separate high-voltage stabilizing supply. Heat is managed via an aluminum die-cast chimney-type heatsink for efficient convection cooling. High-precision single-metal coating resistors are used in the signal path, and specialized low-distortion electrolytic capacitors replace film types where performance is critical. It includes a gold-plated screw-lock pin jack and comes with a 1-meter low-capacitance, low-inductance speaker cord made of seven twisted pairs with foamed polyethylene insulation.
Context
Market
A tested working single unit was listed for C $610.56 with C $115.04 shipping. It is described in current listings as a rare mono block amplifier, reflecting its collectible status among vintage audio enthusiasts.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.