Yamaha CA-2010 Amplifier Review

A very unusual feature of the Yamaha CA-2010 amplifier is that it has the switched option of two modes of operation of the output stages, class A/B or class A operation, the latter being claimed to give even lower distortion. The penalty for class A operation is that the rated output power into 8 ohms drops from 120W to 30W, and all figures in the adjacent table are related to the 120W output.

Measured distortion in this condition was first class and similar excellent results were obtained with class A operation, the high frequency intermodulation distortion being extremely low, and also the power bandwidth extending above 100kHz.

Not only was distortion performance outstanding, but also the noise associated with all the inputs was amongst the best measured in these amplifier reviews and the output noise was good. Because the manufacturer has had the sense to place the ‘muting’ attenuator after the analog volume control, noise was no problem when using headphones and the action of the volume control was found to be very good. Neither the volume control nor the treble and bass tone controls upset the amplifier balance and the tone controls were a delight to use with their small switched steps and sensible restricted range. The defeat tone control switches provided a choice of two well chosen turnover frequencies for each control.

High pass and low pass filters are of the 12dB per octave type with well chosen turnover frequencies at 30Hz and 10kHz respectively and it was noted that the common and unnecessary loudness control was not to be found on the Yamaha CA-2010.

On the output end two sets of loudspeaker terminals are available, with switch selection of either loudspeaker or both in parallel " in which case use 8 ohm speakers.

The basic input selector switch provides for the two tape inputs and the tuner and auxiliary inputs, with a further position selection selecting the phono inputs switch. The latter selects the fixed sensitivity and impedance ‘phono 2’ input or the ‘phono 1’ input which accepts either a magnetic pick-up cartridge with a choice of 99/68/50k ohm input impedance or a moving magnet cartridge with a low input impedance and a sensitivity of 70 microvolts. But amplifier balance was poor using this input " see graph.

The arrangement of the two tape inputs and outputs which do not have DIN connectors is such that tape monitoring is achieved by the input source switch, and the signal to be recorded is selected by a further rotary switch which has positions for all the input sources in addition to positions for the two tape units, such that tape dubbing can be done in either direction. Crosstalk across all selector switches was satisfactory, such that there was little interference from unwanted sources.

In addition to the inputs and outputs already mentioned, the rear of the amplifier also has pre-amplifier output and power amplifier input connections which can be separated by a slide switch.

A final feature is two front panel meters calibrated in millivolts for measuring the record output level, and in decibels and watts into 8 ohms for measuring the power amplifier output. These were fast acting meters which really did indicate peak conditions " amplifier clipping and distortion could be easily read.

Internal and external finish were both good, with excellent and clearly identified circuit boards and components, but access for servicing appeared to be restricted.

Overall this is an excellent amplifier with all the facilities which may be required, but it is of course expensive.

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