Akai AM-U04 (1980)
Stereo integrated transistor amplifier with separate MC/MM phono stages and needle VU meters
Overview
The Akai AM-U04 is a stereo integrated amplifier produced in 1980 by Akai. It features a fully symmetrical, direct-coupled DC amplifier design and includes separate phono stages for moving magnet (MM) and moving coil (MC) cartridges. As the top model in Akai's "U" series within the AM series, it was designed for high-fidelity audio reproduction with a clean, neutral sound. The amplifier includes tone controls, a subsonic filter, and needle VU meters for output monitoring.
Specifications
| Power Output | 2 x 40 W (8 Ω, 20 Hz - 20 kHz, 0.03% THD) |
| Frequency Response | 5 Hz - 100 kHz (-3 dB) |
| Total Harmonic Distortion | 0.03% (at rated output) |
| Damping Factor | 40 |
| Input Sensitivity (Phono MM) | 2.5 mV |
| Input Sensitivity (Phono MC) | 0.25 mV |
| Input Sensitivity (Line/DIN) | 150 mV |
| Signal to Noise Ratio (Phono MM) | 80 dB |
| Signal to Noise Ratio (Phono MC) | 70 dB |
| Signal to Noise Ratio (Line) | 100 dB |
| Channel Separation | 60 dB (MM), 60 dB (Line) |
| Outputs | 150 mV (line), 30 mV (DIN), 1 V (Pre out) |
| Speaker Load Impedance | 4 Ω to 16 Ω |
| Headphone Output | Stereo jack 6.35 mm |
| Connectors | DIN, RCA |
| Inputs | 1 x Phono MC, 1 x Phono MM, 2 x Line |
| Outputs | 1 x Tape Rec |
| Tone Controls | Bass and Treble |
| Filter | Subsonic filter |
| Features | Vu-meters (Needle) |
| Power Supply | 220 V |
| Technology | Transistors |
| Dimensions | 430 x 95 x 310 mm |
| Weight | 7.5 kg |
Design
The AM-U04 uses a fully symmetrical, direct-coupled DC amplifier circuit design and contains discrete internal boards for key functions: Main Amp (AMU-4001A), LED (AMU-4007), Slide Volume (AMU-4008), Loudness (AMU-2003), Bar Meter (AMU-2006), Tone Control (AMU-4003), Selector (AMU-4002), Push Switch (AMU-4001B), and Pin Jack (AMU-4005). Multiple fuse boards support regional power standards (AMU-4006, AMU-4058, AMU-4060, AMU-4059). Key components include LC7556, TA7317P, TA7322P, TA75458S, STK-005011, and STK-3042. The service manual includes procedures for Center Off-Set Voltage Adjustment and Bar Meter Sensitivity Adjustment.
Context
The AM-U04 was the top model in Akai's "U" series within the AM series of amplifiers.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.
Related Models
- Akai AM-A301
- Akai AM-U7
- Akai AM-U-2 (1975)
- Akai AM-A-70 (1978)
- Akai AA-1020 (1972)
- Luxman L-530 (1975)
- Luxman R-404 (1975)
- Luxman RV-371 (1975)
- Luxman SQ-38U (1975)
- Luxman T-14 (1972)