YAMAHA CA-600

Commentary

A pre-main amplifier with a low distortion factor main amplifier.

The main amplifier section uses a pure complimentary service OCL circuit directly connected to all stages, enabling clear playback from ultra-low to ultra-high frequencies. The first stage of the main amplifier also provides stable operation.

When the DC voltage at the output terminal exceeds ± 2 V, the relay is instantly activated and the circuit is cut off. This circuit prevents problems that may damage the speakers or power transistors. This circuit also functions as a power muting circuit, preventing shock noise when the power switch is turned on / off.

Like the CA-800II, the equalizer amplifier consists of a 4-stage NFR-type direct-coupled circuit using a low-impedance transistor. In addition, the emitter-follower type is adopted for the output stage, which allows for a low output impedance. It is driven at a constant voltage of + 50 V to achieve high stability, low distortion factor, and high S/N. The equalizer element combines a evaporated metal film resistor (error ± 1%) and a styrene capacitor (error ± 1% and ± 2%) to achieve excellent characteristics.
Computer circuit analysis (CAD method) has been introduced for circuit design. The board and terminals are wired at the shortest distance so as to improve the distortion factor and S/N ratio, and the best data is obtained from the pattern.

The Phono1 circuit is equipped with an input impedance selection switch so that it can accurately match the load impedance of the cartridge to be used by switching to 3 stages.

The tone control circuit is a two stage direct-coupled circuit with a low-noise transistor. It is a Yamaha system in which NF is applied from the collector of the second stage to the emitter of the first stage.
Also, the adjustment knob is Klix/Klukš top type.

The loudness circuit is based on a unique continuous loudness circuit with a special knob for adjusting the loudness so that the sense of hearing can be adjusted according to the actual listening environment.

The filter circuit uses the same 2-stage direct-coupled circuit as the tone control.

A large power transformer with good regulation is used for the power circuit.

Equipped with a pre-main coupler that can be used to separate the pre-amplifier and main amplifier, -20dB audio muting and tape dubbing switch.

Model Rating

Type	Pre-main amplifier
Main Amplifier Section
Dynamic Power (IHF)	140W (4 Ω) 100W (8 Ω)
Effective power	20 Hz to 20 kHz (both channel drive) : 35W + 35W (4 Ω) 30W + 30W (8 Ω) 1kHz (both channel drive) : 45W + 45W (4 Ω) 35W + 35W (8 Ω) (single-ch drive) : 50W/50W (4 Ω) 40W/40W (8 Ω)
Total harmonic distortion factor	0.1% or Less (Effective Output) 0.04% or Less (at 1W output)
Intermodulation distortion factor (70 hz : 7 khz = 4 : 1)	0.1% or Less (Effective Output) 0.05% or Less (at 1W Output)
Power Bandwidth (IHF, 0.5% distortion factor)	5 Hz to 70 kHz
Frequency characteristic	10 Hz to 100 kHz + 0 -1dB
Input Sensitivity / Impedance	775mV/40k Ω
Load impedance	4 Ω ~ 16 Ω
Damping factor	70 (1 kHz, 8 Ω)
Channel separation	60 dB or More (1 kHz, Effective Output)
S/N (IHF, A Network)	100 dB or more
Residual noise	0.8 mv or Less (8 Ω, Pre + Main Amplifier)
Preamplifier Section
Input Sensitivity / Impedance (1 kHz, effective output)	Phono1 : 3mV/30k Ω, 50k Ω, 100k Ω Phono2 : 3mV/50k Ω MIC : 2.5mV/50k Ω Tuner, Aux1, 2 : 120mV/40k Ω Tape PB A, B : 120mV/40k Ω
Phono maximum allowable input (0.1% distortion factor)	310mVrms
Mic maximum allowable input (distortion factor 0.1%)	245mVrms
Output Level / Impedance (1 kHz)	Tape Rec out A, B : 120mV/2k Ω Pre out : 775mV/2k Ω
Total harmonic distortion factor (Pre-out at effective output)	Phono1, 2 : 0.1% or less Aux : not more than 0.02%
Frequency characteristic	Phono (RIAA deviation) : 30 Hz to 15 kHz ± 0.2 dB Mic : 20 Hz to 20 kHz + 0. 5-2 dB Aux, Tuner, Tape PB : 10 Hz to 50 kHz + 0.5 -1dB
S/N (IHF, A-network Pre + main amplifier)	Phono1, 2 : 80 dB or more Mic : 70 dB or more Aux, Tuner, Tape PB : 90 dB or higher
Tone control	Bass : ± 10 dB (50 Hz) Treble : ± 10 dB (10 kHz)
Filter	Low:50Hz(12dB/oct) High:8kHz(6dB/oct)
Loudness	Continuous loudness corresponding to an equal loudness curve
Audio Muting	-20dB
<General>
Semiconductor used	Transistor : 39 Diode : 6 pcs Zener diode : 6 pcs
Rated power consumption	120W
AC outlet	Power switch interlock : 2 systems Power switch not linked : 2 systems
External dimensions	Width 436x Height 144x Depth 323 mm
Weight	11.0kg