Nakamichi CA-5 Control amplifier, PA-5 Power amplifier

Description

Nakamichi CA-5 Control Amplifier: A Detailed Description

The Nakamichi CA-5 is a highly regarded stereo control amplifier (preamplifier) from the late 1980s and early 1990s, known for its exceptional sound quality, versatile features, and robust build. It was designed to be the control center of a high-end audio system, providing precise signal routing and minimal signal degradation. Key Features and Characteristics:

• Ultra-Low Noise and Distortion Design: Nakamichi emphasized a clean and transparent sound signature in the CA-5, employing carefully selected components and circuit designs to minimize noise and distortion.
• Multiple Input Options: It typically offered a wide array of inputs to accommodate various audio sources, including:
  • Phono: With switchable Moving Magnet (MM) and Moving Coil (MC) cartridge impedance settings, catering to high-quality turntable setups.  
  • CD: A dedicated input for compact disc players.
  • Tuner: For connecting a radio tuner.
  • Aux/Line: Multiple auxiliary or line-level inputs for tape decks, DAT recorders, or other analog sources.
  • Video/Aux: An additional input that could sometimes be configured for audio or video sources.
• Tape Monitoring and Dubbing: Comprehensive tape facilities were usually included, allowing for monitoring the recording process and dubbing between two tape decks.
• High-Quality Volume and Balance Controls: The CA-5 typically featured precision potentiometers for volume and balance adjustments, ensuring smooth and accurate control.
• Subsonic Filter: A switchable subsonic filter was often included to attenuate very low-frequency rumble from turntables, preventing it from being amplified and potentially affecting the speakers.
• Mono/Stereo Switching: A mono switch allowed for summing the left and right channels, which could be useful for troubleshooting or listening to mono recordings.
• Muting Function: A mute switch provided a quick way to silence the audio output.  
• High-Quality Output Stage: The preamplifier stage was designed to provide a clean and strong signal to the power amplifier.
• Elegant and Robust Build Quality: Nakamichi products from this era were known for their solid construction and sophisticated aesthetics. The CA-5 typically featured a clean front panel layout and high-quality components.

Specifications (Based on available information):

• Frequency Response: Typically 5 Hz to 100 kHz (+0 dB, -1 dB)
• Total Harmonic Distortion (THD): Typically less than 0.003%
• Signal-to-Noise Ratio (S/N):
  • Phono MM: Typically 85 dB
  • Phono MC: Typically 75 dB
  • Line Inputs: Typically 100 dB
• Input Sensitivity/Impedance: Varies depending on the input (e.g., Phono MM: 2.5 mV/47 kΩ, Phono MC: 160 µV/100 Ω, Line: 150 mV/20 kΩ)
• Output Level: Typically 2 V (Pre Out)
• Dimensions (W x H x D): Approximately 435 x 63 x 289 mm  
• Weight: Approximately 3.7 kg

Nakamichi PA-5 Power Amplifier: A Detailed Description

The Nakamichi PA-5 is a stereo power amplifier designed to deliver substantial and clean power to drive demanding loudspeakers. It was often paired with the CA-5 control amplifier to form a high-performance audio system. Key Features and Characteristics:

• High Power Output: The PA-5 was known for its robust power output, capable of driving a wide range of speakers with authority. Specifications often cited around 100 Watts per channel into 8 ohms, with even higher output into lower impedances.  
• Discrete Output Transistors: Nakamichi typically employed high-quality discrete output transistors in their power amplifiers, contributing to their sonic purity and reliability.
• High Current Capability: The PA-5 was designed to deliver significant current, allowing it to handle dynamic musical passages and the impedance dips of many loudspeakers.
• Massive Power Supply: A large toroidal transformer and substantial power supply capacitors were usually implemented to ensure stable power delivery and excellent transient response.  
• Protection Circuitry: Comprehensive protection circuits were included to safeguard the amplifier and connected speakers fromOvercurrent, short circuits, and DC offset.
• Clean and Neutral Sound: The sonic goal of the PA-5 was typically to amplify the signal from the preamplifier without adding significant coloration, preserving the nuances of the music.
• Solid and Well-Ventilated Chassis: The amplifier featured a robust chassis with adequate heat sinking to dissipate heat generated during operation, ensuring long-term reliability.
• High-Quality Binding Posts: Sturdy binding posts were provided for secure and reliable speaker cable connections.

Specifications (Based on available information):

• Power Output: Typically 100 Watts per channel into 8 ohms (20 Hz - 20 kHz, 0.1% THD)
• Power Output (4 ohms): Typically 150 Watts per channel
• Frequency Response: Typically 5 Hz to 100 kHz (+0 dB, -1 dB)
• Total Harmonic Distortion (THD): Typically less than 0.003% at rated power
• Intermodulation Distortion: Typically less than 0.003%
• Input Sensitivity: Typically 1 V
• Input Impedance: Typically 20 kΩ
• Signal-to-Noise Ratio (S/N): Typically greater than 110 dB
• Dimensions (W x H x D): Approximately 430 x 135 x 370 mm
• Weight: Approximately 15 kg