Yamaha PSS 360, 460, 560, 470, 570

[billdepo]

Hi there,

Just wondering if anyone had attempted a bend on any of these machines, and if so how successful was it. I have a 460 a 560 and a 570 at the moment and think they're great - just gotta get me the 360 and 470 now.

[bendboy]

I have a PSS-470 and a 570, they are wonderful to bend-and usually pretty cheap (1987 keyboard) I will post some noise and info soon-I'm going to bed!! Yawn!!

[zoomtheline]

oh man I have been looking for a 460 for ages....as I had one as a kid.
I'm really happy to hear that its bendable aswell, its making me want to
find one quicker though.....and they seem to be quite hard to find aswell.

[bendboy]

(Note:these are edited posts I did on the google benders group in october)

A 470 and 570 have exactly the same main board with different CPUs,
with the 470 missing parts used in the 570 for rhytm sounds.
The extra chips include a rhythm chip, its DAC and about 5 op-amps and support
parts. The output is stereo on a 570, but the keyboard tones still are not!
So this means:
A:the 570 does NOT lose poly notes with rhythm on,
and has a full 'Keyboard rhythm' mode.
B:you can bend the keyboard tone and rhythm lines separately!!

WARNING:
DO NOT get a 470 with the idea of 'converting' it to a 570!!
The wiring to the front panel is different,
even for a lot of the same functions!! (I learned this the hard way!!)

For both, besides a demo button (present on the 360/460),
I don't think too much is addable-jury is out on that.
A 470 service manual gets you a 460 manual +extra pages
for the 470 'differences' which seem only cosmetic-why put out 2 of the same machine? Ask Yamaha!
As far as bending is concerned, both are VERY rich with bends:
Data/control line messing, isolation, bridging. (disturbs notes/rhytms, everything-very controlable like the SK-1)
Dac bias, voltage, etc. (nasty guitar-like distortion) direct speaker feedback possible.
The simulated stereo system is cool; modded for full signal you can send  send external signals through it,
sound warp/pitch bend or internal feedback. (raising the sweep rate can make some really odd sounds)
I will post some sounds sooner or later....hey, I'm doing research here!

The PSS 480 on the other hand is a bit of a dissapointment, as far as bending is concerned.
ANY data line mess AT ALL will crash it,
99% of the time with no sound. (It did start playing many samples backwards once, for 10 seconds!!)
There is 5 lower notes you can add (key matrix), but with an odd really low cool tone to it
that can't be changed. I am still investigating...this unit is a BEAR
to open and work on, one side is ALL ground plane, so its hard
to drill holes, and all is surface mount stuff, but for the roms. There
are tons of jumpers with no labels.....did i mention the oodles of small screws? fun.
I did find 1 good bend area-isolatie the data/address lines of the Rhythm chip and
its rom. Then mess a LOT with rhythms!
Some of the rom pins are quite musical, and can add some gritty
tones to the sound-this varies a lot depending on what is playing.
Oddly, both the rhythm chip and the main sound chip have SEPARATE
clock crystals, so pitch bending through external oscilators should
be interesting...
Some research- the 580,680, and 780 are also part of this line,
the 680/780 have drum pads below the keyboard(!) and a pitch
bend wheel, and MIDI through (along with IN and OUT).
I am hoping the pitch bend wheel is addable to the 480,there's got to be more in there..

Part#2
The PSS 570 has a special mode that is NOT obvious-the bass and
chord waveforms used by the rhythms can be set by the digital synth by turning on the
Bass/chord voice button, and setting either one or both to '5' Then
turn on the digital synth-it now controls the voice(s) set to '5'!!
It can't seem to do this AND the keyboard at the same time...
One of the reasons I picked up a 470 when I played it was the
'action' of the sliders in the digital synth. I really thought it was
analog control! They respond VERY fast to being slid around
while a note is playing!!! The switches are constantly pressed
by a metal lever directly onto the PCB,, but I found that just a 'tap' of contact will set a mode change
too (the processor seems to use the 'last input recieved' from a switch,
not the constant press) this is good news, because a 4017 timer
circuit+4066 switches can be made to 'trill' between certain settings quickly-this
could even apply to the voice buttons!
I already found if the decay slider is moved while a tone is evolving, you can freeze it wherever you want!
More on the PSS 470...some real nice guitar-like distortions messing with
the DAC and the sound chip, often sounding fine with 1 note, and
totally breaking up with 2 or more-the harmonics are incredible! Many pins glitch real nice, but with one
big problem-most of the bends make it really loud, or unpredictable
volume. The volume control need to be modded to go to 0 volume by jumpering 2 resistors.
Also, the phono jacks on the back
are actually SPEAKER outputs, but work fine as line outs if the volume is set low
(the speakers are NOT turned off!) 
I am  investigating the Stereo simulator (leslie-ish panning)
It uses a variable clock with BBD device for delay, feeding back to the right and
left channels out-of phase. The BBD is a MA3206...there is an
'08, an '09, and many others-some are drop in replacements-and have
more delay!! too bad they are not made anymore-and expensive....
Maybe I could hack in a SAD-1024 BBD?
Looks like at least 3 distortion controls so far!
Work continues-sounds soon!

Mess with it!!

[Arcturus]

if you get the chance, could you PLEASE post some internal pictures of your bends to the 470? Im working on one now, and all I can find are some crazy crashes.

please.

[iwillbeacircuitbender]

The Yamaha PSS 560 and 570 use the YM3301 as their main FM chips (edward-d-tech, pinout below)
http://www.dtech.lv/files_ym/YM3301_pinout.png

The Yamaha PSS 460 uses the YM3812 (same chip used in some old Soundblaster OPL2 cards (edward-d-tech)
Datasheet below:
http://www.dtech.lv/files_ym/ym3812.pdf