Pioneer SA-8500 II Amplifier Review
Whilst the available number of inputs are limited to two phono cartridges, tuner and auxiliary plus two tape units, the facilities offered by the Pioneer SA-8500 II amplifier are comprehensive and the number of inputs should be adequate for most practical installations.
All input impedances and levels are well conceived, with a bonus that the capacitive components of the phono input impedance can be switch-selected by a small front panel control which is calibrated as 100/200/300/400pF but in fact gave input capacitances of 35/120/235/345pF. In practice the available selection is fine, and this facility is a very useful one.
A high pass and a low pass filter may be switch selected, both being 6dB per octave filters with sensible turnover frequencies. It is felt however that the rate of attenuation of the high pass filter should have been more, so far as the phono input is concerned.
The Pioneer SA-8500 II has treble and bass tone controls, but no presence control, the tone controls being eleven position switches which operate in conjunction with further switches which select the turnover frequency from a choice of three in each case. This arrangement gave excellent subjective results and the steps of cut and boost were adequately small whatever the selected turnover frequency.
Like the tone controls, the volume control is also a switched attenuator which works in conjunction with a ‘mute’ switch which provides an extra 20dB of attenuation over and above the volume control range of 70dB in 2dB steps plus an ‘off’ position. This range was quite adequate for both loudspeaker and headphone listening, and the balance between channels was unaffected by the volume control or by the tone controls.
The balance control itself is of the full range variety which can cut off either loudspeaker, but the operation around the centre position was generally good for correcting balance, but can be bettered.
Further front panel controls include a mode switch which has stereo, reverse stereo, left, right and sum positions. In addition, there are tape monitor and tape dubbing switches for the two tape connections, one of which has a DIN compatible connector in addition to the phono sockets which are used for all inputs.
The rear panel includes phono sockets for access to the output of the pre-amplifier and the input to the power amplifier for inserting equalizers etc and the clip type terminals for two sets of loudspeakers. Either or both of the sets of loudspeakers can be selected by a front panel selector switch which also has an ‘off’ position. Also on the front panel there is a standard headphone jack socket.
The overall standard of construction was good, but it was noted that no components on the good printed circuit boards were identified for servicing, and whilst the instructions include a circuit diagram, no layout information is provided.
From an operational point of view this amplifier gave good performance, with all controls behaving well and no troubles from switch clicks or crosstalk between inputs or across the tape monitor switch.
The rated power of 60W per channel was readily available into 4 ohms or 8 ohms, with a good harmonic distortion performance and intermodulation distortion performance at audio frequencies. However, the intermodulation distortion rose to a rather high level outside the audio band at half power.
The noise performance of all inputs was very good and the amplifier generally gave a good account of itself, and considering its price it is felt that this unit has a lot to offer.