Yamaha PF10, PF15
Electronic pianos have come a long way in the last decade, and this latest breed from Yamaha utilises the same frequency modulation system of synthesis that made the DX synthesisers an instant legend.
The PF15 has an 88-note A-to-C keyboard and as well as being velocity-sensitive, the keys have a weighted action that will appeal to musicians who've been trained on a conventional acoustic piano.
Internal amplification is provided for practice or domestic use, and this is fed to two built-in loudspeakers via a stereo chorus circuit that may be switched in or out as required.
For recording or concert use, two line level outputs are provided so that the full effect of the stereo chorus may be maintained, and the output level is independent of the volume slider.
A choice of ten different voicings is available at the touch of a button, and a transpose facility allows the pitch to be tuned up or down a fourth in accurate semitone steps, a separate tuning control facilitating fine tuning to other instruments.
The PF15 is no lightweight at 77lbs, its steel construction making it a very substantial piece of engineering, although its sleek design means that it will fit in with most front room furniture. Overall size is 52" x 4¾" x 15⅜".
The distinctive brown paintwork is complemented by simulated wooden end cheeks, while two matching plastic grilles house the speakers at either end of the front panel for maximum stereo effect within the confines of the instrument itself.
Internally the construction is surprisingly simple and uncluttered, as all the sound generation is handled by Yamaha's own custom-built LSI circuits, which keeps the component count down to an absolute minimum. The built-in amplifiers are capable of providing five watts each and, although this doesn't sound a lot, in fact it's quite sufficient for domestic use or practice.
Because of the preset nature of the instrument, controls are a bit thin on the ground, and the front panel sports only six pushbuttons and two sliders if you don't count the mains switch. To the extreme left is the transposition slider, which has click stops every semitone allowing C to be transposed down to G flat or up to F: definitely a boon for club performers who back different singers every night, each one demanding the same songs but in different keys.
Next come the voice selector buttons which are arranged in two banks of five; the first button selects the bank and then the next five buttons select the voices from that bank.
Bank one contains three piano and two harpsichord voices, whilst bank two offers the choice of a further three piano voices, vibes and clavinet.
Next button along switches in the stereo chorus which is fully preset, being based on a charge-coupled, delay line circuit. The pseudo stereo effect is produced by inverting the phase of the time-modulated component fed to one channel, which is a pretty standard way of producing this effect, but one shortcoming of this method is that a stereo recording replayed in mono is likely to cause the effect to disappear, as the two antiphase components cancel each other out.
To the right of the chorus button is the volume slider which is calibrated zero to ten (just for a change), and the operation of this control should be no problem to anyone who is bright enough to find it.
To the extreme right of the front panel is the power switch (accompanied by the obligatory LED) and the output is muted for a few seconds after switch-on, presumably to hide embarrassing sounds that might otherwise ensue.
The back panel conceals seven sockets recessed safely behind a chocolate brown facade, each one being labelled in the same shade of chocolate brown just to stop things getting too easy. Facilities on offer here are line input, sustain, key hold, stereo output and a choice of two types of headphone socket. Also lurking here, disguised as another socket, is the fine tuning control.
The line input allows another musical instrument or rhythm machine to be played through the internal speakers, while the sustain socket connects to a momentary action footswitch, so that a reasonable approximation of the sustain pedal on a conventional piano can be put to use.
The hold function is one not to be found on an acoustic piano: connecting a footswitch to this socket allows notes or chords to be sustained indefinitely while new melodies are played over the top. Stereo line output is via two separate jack sockets so that only one may be used if mono is required, and a choice of standard quarter-inch or mini jack headphone sockets is thoughtfully provided, so that you can use the 'phones off your Walkman or whatever.
Since playing the piano is not my forte, I enlisted the help of one Mick Jones, who owns and plays both a grand piano and a Fender Rhodes in addition to various synths.
His first reaction (apart from 'Cor, I thought my Rhodes was heavy!') was approval for the weighted keyboard, which responded in a positive and re-assuring manner, being if anything a little more positive and even than that of an acoustic piano.
All six piano sounds were found to be useful, though it should be mentioned that they are simulations of electric instruments rather than acoustic ones. One preset was discovered to be quite close to the Fender Rhodes sound, being a little brighter and generally less muddy, and indeed it was at this point that Mick suggested swapping his Rhodes for it in the sure and certain knowledge that no one would notice.
There are two harpsichord presets which also met with complementary approval, but it was the vibes and clari-chord voices that elicited the most praise. All these voices sounded good with or without help from the stereo chorus, and the only criticism revolves around the level of background noise. The chorus is noticeably noisy when switched on (though not unusably so) but another source of noise also gave cause for concern. If a low note is played using one of the piano voices so that there are few high frequency components, a burst of noise is heard during the note, though this dies away with the note leaving silence when the piano is not being played.
This is not a noise gate, as it's possible to hear the noise being progressively low pass filtered during the decay, so presumably some form of tracking filter or dynamic noise reduction is being employed.
Although probably adequate for live performance work, the noise factor could be a real problem when recording, so this must be borne in mind if you're in the process of deciding which electronic piano to buy.
Using the same circuitry as the PF15, the 10 features a reduced keyboard length, effectively losing one octave from either end. The keys are still velocity-sensitive but cost has been saved by using a standard sprung plastic keyboard instead of the more sophisticated weighted action of the PF15.
All voices and facilities are otherwise identical, but it should be noted that the sustain pedal provided is a simpler device than the elegant unit supplied with the PF15.
Both these pianos offer ten very useful preset sounds and could certainly be used instead of the popular electro-mechanical pianos that until now have been pretty much the industry standard.
Yamaha's FM synthesis techniques produce a bright, harmonically rich sound, and the only negative comment must be aimed at the high level of background noise, which is really not on for instruments of this price and calibre.
With this reservation then, I feel Yamaha have succeeded in building a fine-sounding pair of pianos that look and feel first class.
Review by Paul White
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