Korg Poly800/EX800 Users

this one must have been dealt with before:

i just just got back to my ex800 after a long time. 
it is still unmodded, and the battery clip i'd installed 
instead of the original soldered battery had come undone, 
so no patches, and the usual slow-rise noise with delayed 
vcf LFO patch(...). but my buttons are fer sh*t: 5 almost 
doesn't work at all, 3 is dodgy...well, they're all in a 
pretty rough state, makes progging a nightmare.

so, what is the info on this? must i remove that board and 
somehow open up the switches and clean them? i'd like to sort 
this out before i attack the mod.

2nd question/issue is something i have wondered about for a 
long time: the difference between the pulse wave and the saw: 
on my 800, the 'saw' sounds almost the same ('square-ish'), 
just louder. i wouldn't say either is distinctively square 
or saw...kinda in the square department more, and i'm not 
really hearing a distinctive 'saw/ramp'. is this normal?

number 3 is: could somehow explain, or do a sketch for me, 
of wha exactly the envelope terms 'slope' and 'breakpoint' 
mean?(ok, so i was mucking around with it with the VCF EG 
inverted, and that didn't help clarify much- again, the default 
noise patch)...pathetic, really, when i've had this thing for???
well over 15 years.

On 14/07/12 20:41, k9k9dog wrote:

> so, what is the info on this? must i remove that board and
> somehow open up the switches and clean them? i'd like to sort
> this out before i attack the mod.

Just change them.  They cannot be satisfactorily cleaned up.
You do not want to be getting all those screws out more often than you 
have to.

> 2nd question/issue is something i have wondered about for a
> long time: the difference between the pulse wave and the saw:
> on my 800, the 'saw' sounds almost the same ('square-ish'),
> just louder. i wouldn't say either is distinctively square
> or saw...kinda in the square department more, and i'm not
> really hearing a distinctive 'saw/ramp'. is this normal?

The saw wave is generated by turning on all four octaves and setting the 
square/saw to saw - what it does is it makes each octave half the level 
of the one above.  You get a neat 4-bit digital sawtooth ;-)

> number 3 is: could somehow explain, or do a sketch for me,
> of wha exactly the envelope terms 'slope' and 'breakpoint'
> mean?(ok, so i was mucking around with it with the VCF EG
> inverted, and that didn't help clarify much- again, the default
> noise patch)...pathetic, really, when i've had this thing for???
> well over 15 years.

You've got ADSR on a normal synth, right?  In the Attack phase, the 
envelope builds up until it reaches maximum, then flips to Decay phase 
where it drops until it hits the Sustain level, and of course the 
Release time on key-off.
Well for ADBSSR, the Attack and Decay phases are the same, but Decay 
will hit the Breakpoint and then decay at a different rate set by Slope, 
until it hits the Sustain level.

-- 
Gordonjcp MM0YEQ

On Saturday 14 July 2012, 21:13:56, Gordon JC Pearce wrote:
> On 14/07/12 20:41, k9k9dog wrote:
> > so, what is the info on this? must i remove that board and
> > somehow open up the switches and clean them? i'd like to sort
> > this out before i attack the mod.
> 
> Just change them.  They cannot be satisfactorily cleaned up.
> You do not want to be getting all those screws out more often than you
> have to.

I'd have loved to swap them out, but I didn't find any suitable replacements 
about 4 years ago when two of them got so flaky that the synth became almost 
unusable.  So in the end I did take the switches apart and clean them and 
all in all that probably took longer than what swapping them out would have.  
Screws were the least of the problem, we're talking EX-800 here, not 
Poly-800.  You really need to be careful not to break off the retention tabs 
(or at least not all of them, that plastic _is_ old by now) or you won't be 
able to get them back together.  I got everything working again, but you 
should have a backup plan — mine was to rack-mount the whole thing into a 2U 
case and re-wire the frontpanel accordingly.  Which is what I'll likely have 
to do if they ever go bad again because I don't think they'd surveive 
another round of taking them apart.


Regards,
Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

SD adaptations for KORG EX-800 and Poly-800MkII V0.9:
http://Synth.Stromeko.net/Downloads.html#KorgSDada

thanks for infos, lol, especially the breakpoint slope 
business. (just having trouble visualizing it)
i'll be *very* careful approaching those button covers..
impossible to find if damaged!!
are these going to be 'tact' switches? (let's have a look...)

btw, as i read in the manual that the joystick on the keyboard 
version can be used for parameter editing, what's the option 
for us EX800 rack owners? there's plenty of space on that panel 
to fit some kind of joystick device. has anybody done this? 
would do away with need for rotary encoders etc. was thinking 
that a playstation-type xy stick could be neat and unobtrusive, 
but not sure the action would be correct, as it is sprung. it 
also has a down-click function, which could be used as an additional 
write button(?just an idle thought...).

i found, in previous use in a rack, that the main drawback of the 
unit was that you tended not to want to go editing patches when you 
were 'in the flow' of things, and i'd go to the juno106 i had at the 
time for that instead. what i mean is that my main interest in parameter access is in tweaking a voice quickly, within a mix, as 
opposed to loads of realtime controllerisms,(although that's nice to 
have too).i'm going to try to find those demos Mike did using 
realtime controllers, but if (you) have any new ones, using say a 
Novation Remote, please link us up! i'm really not sure about sending 
NRPNs even now, and have never done it successfully. Last time i 
tried was using an atari, and trying to build a mixermap that could 
do it. something wasn't done right and i stuck with sysex. (and of 
course, that means i'm accustomed to the idea of sending controller data offset from note-on/offs)

--- In korgpolyex@yahoogroups.com, ASSI <Stromeko@...> wrote:

>
> On Saturday 14 July 2012, 21:13:56, Gordon JC Pearce wrote:
> > On 14/07/12 20:41, k9k9dog wrote:
> > > so, what is the info on this? must i remove that board and
> > > somehow open up the switches and clean them? i'd like to sort
> > > this out before i attack the mod.
> > 
> > Just change them.  They cannot be satisfactorily cleaned up.
> > You do not want to be getting all those screws out more often than you
> > have to.
> 
> I'd have loved to swap them out, but I didn't find any suitable replacements 
> about 4 years ago when two of them got so flaky that the synth became almost 
> unusable.  So in the end I did take the switches apart and clean them and 
> all in all that probably took longer than what swapping them out would have.  
> Screws were the least of the problem, we're talking EX-800 here, not 
> Poly-800.  You really need to be careful not to break off the retention tabs 
> (or at least not all of them, that plastic _is_ old by now) or you won't be 
> able to get them back together.  I got everything working again, but you 
> should have a backup plan â€" mine was to rack-mount the whole thing into a 2U 
> case and re-wire the frontpanel accordingly.  Which is what I'll likely have 
> to do if they ever go bad again because I don't think they'd surveive 
> another round of taking them apart.
> 
> 
> Regards,
> Achim.
> -- 
> +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+
> 
> SD adaptations for KORG EX-800 and Poly-800MkII V0.9:
> http://Synth.Stromeko.net/Downloads.html#KorgSDada
>