Yamaha • DX-5
Yamaha's DX-5 slots in somewhere between their legendary DX-7 and flagship DX-1 synthesizers. Under the hood the DX-5 is almost identical to the DX-1 except the DX-5 has done away with the heavy wood-paneling and has a less fancy keyboard (no more ployphonic aftertouch) and is more affordable. With its dual 6-operator FM synth engines the DX-5 is like having two DX-7 synthesizers in one, and then some! The DX-5 has 64 performance memories which can be loaded or saved to cartridge, while the DX-7 has only one manual performance memory. This improves the versatility for live performance and makes excellent use of the dual engines. However, one thing to consider is that the MIDI implementation, while adequate, does not qualify it as a master keyboard, in particular, the DX-5 (like the DX-7) sends only 99 as the maximum velocity, not 127. In addition, the DX-5 is slightly noisier than the DX-7.
Although the DX-5 is a digital synthesizer, its sounds are unique and fresh with an analog/digital hybrid feel. Programming however, is not at all like analog synth programming. All DX series synths use Frequency Modulation (FM) synthesis and all are rather difficult to program or, at least, difficult to understand what to program. The DX-5 is no exception to this rule except that its layout, parameter buttons and displays are much better than typical DX synths.
For performances, the DX-5 shares the DX-1's bitimbric ability to play two patches from memory (Channel A and B) with the keyboard in layer or split mode and the polyphony reduced from 32 to 16 voices. That's a very cool ability for an old synth, especially a DX type synth. Imagine playing bass in one hand and some other wacky sounds in the other hand. You'd have to get a couple TX-7s or DX-7s to achieve that otherwise (of course this may be cheaper than getting a DX-5 anyway). The DX-5 remains a very high quality vintage instrument and if you've got the money to burn and a desire for a unique instrument from the DX line of synths, this is the one! It has been used by Kitaro.
If you want a real DX sound, this is probably the best you're going to get (other than a DX1), better than a DX7, and truer than DX7 II even. But if you want the best FM hardware synth, find an FS1r.
Of course, you can likely get more out of NI's FM8 more easily, but it's not quite the same as hardware, is it?
I should also mention that the PLG150DX only acts like a DX7, not a DX5. Remember that the DX5 is bitimbral unlike the original DX7.