Denon PMA-737 Amplifier
The PMA-737 has a domestically more than adequate power rating of 55 watts-per-channel into 8 ohms, and versatile facilities. Thus there are no fewer than six source selector keys: tape 1 and 2, tuner, video/aux, DAD (CD player) and phono, this last being switchable for moving-magnet or moving-coil cartridge. The tape recording outlets can be switched to record the source in use, or allow tape dubbing, or simultaneous recording on both machines. Other controls include bass, treble and balance (all with detent centre settings), subsonic filter, loudness contour, switching for A and B speaker systems, headphone socket and a large calibrated volume control.
The rear panel carries 10 pairs of phono sockets, plus an alternative 5-pin DIN socket for the Tape 2 in/out, and two sets of spring-loaded loudspeaker terminals. The circuit configuration is called "non-feedback" and involves the introduction of a distortion cancelling servo system. Direct coupling is used throughout, and the power supply unit is based on a very substantial transformer.
How it performed
Up to 74 watts could be reached before visible waveform clipping occurred, and the 55 watts rated level produced a very low distortion figure of 0.015% including noise. Clearly there is a very substantial boost of both bass and treble at low listening levels-but this is apparently just what some people like. Signal-to-noise ratio was a remarkable 102d B weighted on high level inputs, and still a very acceptable 83dB on magnetic pickup. Residual noise on the CD input was completely inaudible with the volume control turned t o maximum gain.
In use, all controls performed smoothly and discreet LED indicators lit up to show the status of source selection, etc. Subjectively the amplifier made a very good impression with clear-cut transients and well -defined bass. The stereo stage was wide and produced a good feeling of depth from discs and tapes of known excellence under these headings. In term s of so und quality and versatility the PMA-737 represents very good value.