Don’t confuse the Yamaha Plug-In Boards (aka PLG) with simple ’expansion boards“ that the competition offer. All those do is add more ROM sounds. The Yamaha PLG boards add whole new synthesizers complete with their own DSP effects units, added notes of polyphony, etc. For instance, when you add the PLG150-AN board, you get the equivalent of a Yamaha AN1X synth, which in turn is a modernized digital analog-physically-modelled equivalent of the classic Prophet 5 synthesizer of yore. Complete with five notes of polyphony in addition to the S-80’s own! 256 presets and room for 128 user patches at a time! It also has its own DSP effects units, including a Guitar Amp Simulator for realistic overdriven-amp distortion effects, its own 3-band EQ, and an EQ that works on the S-80’s own sounds!

Would you prefer a slightly more modern ’vintage” synth? How about the PLG150-DX, which is the equivalent of the classic Yamaha DX-? Note: this is not just a collection of DX-like sounds, this is the actual FM synth engine of a DX-7, on a single plug-in card! You can download any DX-7 (and DX1, TF1, TX116, TX816, TX7, DX5, DX72FD, DX72D, DX7S, TX802, etc.) sounds from the Internet or third-party voice banks into this thing and they’ll work (not to mention making your own patches from scratch)! Because they“re the real thing, they can respond wildly to velocity and aftertouch controls, etc., just like the original, but unlike any mere samples can even think about imagining about dreaming about doing! Sixteen notes of additional polyphony all its own, and a whopping 912 presets included! I’d hold off on it if I were you, though, since I suspect that Yamaha may be replacing it soon: their new FS1[R] synthesizer is a wonderful modernization of the FM synthesis technique, with Formant Shaping and Formant SEQuencing capabilities added for awesome new powers far beyond what the DX could do, yet it remains fully DX-compatible. I expect that before too much longer we’ll be seeing a PLG-150FS board (Yamaha would be fools not to), which would make the DX board obsolete.

Others include the PLG100-XG, which adds the equivalent of an MU-50 into your S-80, which makes it fully Level 1 XG compliant (it’s already XG compliant in terms of effects and NRPNs, but it lacks the XG voice set). Note also that the Level 1 XG voice set also includes a “TG300B emulation mode” which is a legal euphemism for “completely compatible with Roland’s original Sound Canvas and its GS, right down to the SysEx/NRPN level!” This PLG card adds three DSPs of its own (Reverb, Chorus, & Variation/Insertion), each of which has at least a dozen, if not dozens [especially the Variation/Insertion unit], of fully parametric settings), and 32 more notes of polyphony, to support its 480 XG voices (676 total counting the ones for the Roland GS mode) and 12 drum kits (21 total counting the ones for the Roland GS mode). For most XG units that take plug-in cards, adding this unit would be mostly redundant, but not for the S-80 (and S-30) which lack the XG voice set.

On the other hand, the situation is reversed somewhat with the PLG150-PF board. This one has 136 high-quality sampled piano and other keyboard sounds, but I think they’re pretty much the same as the sounds already in the S-80. It does add 64 notes of polyphony (the main reason for adding one to an S-80), and four DSP units (Reverb, Chorus, Insertion, and a two-band EQ) of its own.

The PLG100-VH adds no sounds or polyphony, just an effects unit: but what an effects unit! This is the same Vocal Harmonizer chip found in the PSR-740, 8000 and 9000, and the Clavinova CVP-107 (also, this very board, and the one I will describe next, were the first two PLG cards ever and came pre-installed into the first PLG host unit ever: the MU-100R rack-mount professional Level 4 XG tone generator). Sing into the microphone while playing a chord and get up to two additional voices (and your own continues to sound unless you say otherwise, for a total of three-part harmony!), perhaps even gender-shifted, singing musically-proper harmony in your words and your voice, right back at you! (Let’s see a mere expansion board for a Roland or other competing synth do that!)

Finally, there’s the PLG-150VL, which is my personal favorite. This baby only adds one note of “polyphony,” but what a note! VL stands for “Virtual Lead,” and that’s exactly what this is. It has 255 presets, of which 128 are designed especially for use with a wind controller such as a Yamaha WX-5 (looks like a truncated clarinet). This is Physical Modelling at its best! It’s the equivalent of a Yamaha VL-70m. Imagine truly realistic, right down to the very real expressiveness, wind or brass solo such as performed by a very capable soloist. The VL can do that. Bowed or plucked strings with all the nuances the most competent player could do? The VL can do that. Wild new synth effects with awesome expressiveness that can make you forget all about “vintage” sounds? It can do that, too. Roll your own sounds? Yep! DSP effects engines of its own? It’s in there!

With all of this available, the only real problem (besides moolah) is trying to pick just two to install, since the S-80 only has two PLG slots! Fortunately, there are rumors of an external 7-slot expansion unit coming, that will expand any existing PLG slot into seven, with its own power supply. Something else to have to lug around to gigs, though.