Analogue-sequencer

As far as I remember, I had this problem before I did the OS 
upgrade: when I enter pattern edit mode I get a constantly 
repeating message on the screen saying "Step 13 Velo 20", 
as if the Velo pot of step 13 is constantly touched. The 
update frequency is about 4Hz.

If I change the step 13 Velo pot to some other value, the 
repeating message reflects the updated Velo message. 

Sometimes it gets triggered by some editing some other step, 
but the last time I could leave pattern edit mode, enter it 
and there it was again. 

It happens in stopped or play mode.

Looks like a hardware problem? Bad cable?

- Robert

Hi Robert,

> As far as I remember, I had this problem before I did the OS 
> upgrade: when I enter pattern edit mode I get a constantly 
> repeating message on the screen saying "Step 13 Velo 20", 
> as if the Velo pot of step 13 is constantly touched. The 
> update frequency is about 4Hz.
> 
> If I change the step 13 Velo pot to some other value, the 
> repeating message reflects the updated Velo message. 
> 
> Sometimes it gets triggered by some editing some other step, 
> but the last time I could leave pattern edit mode, enter it 
> and there it was again. 
> 
> It happens in stopped or play mode.
> 
> Looks like a hardware problem? Bad cable?

Not likely to be a bad cable - either a bad pot, or a bad multiplexer,
or possibly just a bad contact in the IC socket.
It hasn't been doing this since you got it, has it ?
Does the pot cover it's normal range of 1 to 127 if you move it from one
end to the other ?
By how much does the value change when it's constantly repeating ?

The pots are all fed with 5 volts, and each outputs a voltage between 0
and 5 volts depending on their position.
These voltages are selected in turn by the multplexers (4051 ICs), and
each voltage is fed to an 8 bit analogue to digital convertor.
The convertor has a range of 0 to 255, but this range is reduced to 0 to
127 by dropping the last bit before it's passed to the main code.
Also, the code that checks to see if the value has changed only acts if
the value has changed by 2 or more - this is so that if the pot is
positioned just on the boundary between one (8 bit) value and the next,
it won't flicker between them.
So for the pot to be seen as being constantly 'touched' takes quite a
bit of variation in the voltage.

The quick way to check whether it is the pot or the multiplexer causing
the problem would be to swap over the two multiplexer ICs on the upper
pot board. If that moves the problem to pot 5, it's the multiplexer. If
not, it's the pot.

Cheers,
Colin f

On Thursday 15 January 2004 20:02, Colin f wrote:
> Not likely to be a bad cable - either a bad pot, or a bad
> multiplexer, or possibly just a bad contact in the IC
> socket. It hasn't been doing this since you got it, has
> it ? 

Not that I remember. I'm now sure I had this problem a 
couple of days ago, and maybe earlier.


> Does the pot cover it's normal range of 1 to 127 if
> you move it from one end to the other ?

I studied it some more and it looks like I can stop the 
messages van I move the velo value in the range > 105 or 
so. 

It also looks like *two* similar messages are intermixed. 
Like two pots are reporting changes. If I turn down the 
step #13 velo pot to value 1, I can clear see that a 
message with value 9x (ninetysomething) is mixed with the 
message reporting the 1 value. That other message also 
seems to have an other step number.

> By how much does the value change when it's constantly
> repeating ?

As said above, it is alternating with a message from another 
step with its own value. Don't know yet which step it is.


>
> The pots are all fed with 5 volts, and each outputs a
> voltage between 0 and 5 volts depending on their
> position.
> These voltages are selected in turn by the multplexers
> (4051 ICs), and each voltage is fed to an 8 bit analogue
> to digital convertor. The convertor has a range of 0 to
> 255, but this range is reduced to 0 to 127 by dropping
> the last bit before it's passed to the main code. Also,
> the code that checks to see if the value has changed only
> acts if the value has changed by 2 or more - this is so
> that if the pot is positioned just on the boundary
> between one (8 bit) value and the next, it won't flicker
> between them.
> So for the pot to be seen as being constantly 'touched'
> takes quite a bit of variation in the voltage.
>
> The quick way to check whether it is the pot or the
> multiplexer causing the problem would be to swap over the
> two multiplexer ICs on the upper pot board. If that moves
> the problem to pot 5, it's the multiplexer. If not, it's
> the pot.

I'll give that a try, tomorrow, if Boele is OK with it.

- Robert

I'm just sorta in the middle of writing an article that basically
whinges about all the cool stuff we lost when we moved from CV/Gate
sequencing. Well, it passes the time.

Anyway, one of the things I really enjoy with my twin ARP sequencers
is mixing their outputs and the running the result through a voltage
quantiser. By having sequences that are different lengths/clock
division, you can get these wonderful patterns that evolve in a
fascinating way. OK, you get wrong notes too unless you consider every
possible addition that might happen...

I was wondering whether it might be possible, one day, when you're
like, not busy*, to have a special P3 MIDI Channel definition called,
oh, "MonoMix" so that any tracks set to this knew that only one note
should be produced, no matter how many P3 tracks were set to the same
MIDI channel. Adding the MIDI notes would then be possible using some
maths but also other mathematical functions and processes could be
performed. I know it's the kind of thing that MIDI really isn't good
at. I mean, adding two voltages is easy but try adding two MIDI
events. 

Time to invent some kind of clever external controller/processor box
maybe?

OK, I'm on the shortbread again, waiting to drool over Carrie-Anne
Moss...

Paul

*2012 is free, I believe, just prior to Ragnarok.
---
Paul Nagle / Soft Room Music
Email: paul@softroom.co.uk www.softroom.co.uk
                           www.BogusFocus.com

> It also looks like *two* similar messages are intermixed. 
> Like two pots are reporting changes.

That makes it sound much more like a failed 4051.

> If I turn down the 
> step #13 velo pot to value 1, I can clear see that a 
> message with value 9x (ninetysomething) is mixed with the 
> message reporting the 1 value. That other message also 
> seems to have an other step number.

If you go to the controller edit mode, the changing knobs will activate
their step LEDs (cc is auto set active when the value is changed), so
you should be able to see which other one it is.

Cheers,
Colin f

> Anyway, one of the things I really enjoy with my twin ARP sequencers
> is mixing their outputs and the running the result through a voltage
> quantiser. By having sequences that are different lengths/clock
> division, you can get these wonderful patterns that evolve in a
> fascinating way. OK, you get wrong notes too unless you consider every
> possible addition that might happen...
> 
> I was wondering whether it might be possible, one day, when you're
> like, not busy*, to have a special P3 MIDI Channel definition called,
> oh, "MonoMix" so that any tracks set to this knew that only one note
> should be produced, no matter how many P3 tracks were set to the same
> MIDI channel. Adding the MIDI notes would then be possible using some
> maths but also other mathematical functions and processes could be
> performed. I know it's the kind of thing that MIDI really isn't good
> at. I mean, adding two voltages is easy but try adding two MIDI
> events. 

The aux controller to 'transpose by track n', will allow you to have any
other track's current note value 'added' to the note value for that
step.
So setting up a pattern on track 2, with 'transpose by track 1' on every
step will give you this effect.
Or you could use track 3 as the 'summed' track, and alternate between
transposing from track 1 or 2, and do very weird stuff.
Or use all 4 aux controllers to add up to 5 tracks together.

Cheers,
Colin f

> It's step #9 that is also emiting signals.
> Does this mean anything?

Interesting. Step 9 is input 0 on the 4051, step 13 is input 4.
The tracks for these two run next to each other for a short distance -
there could be a connection between them.
But I think a bad 4051 is more likely.
If Boele let's you open it up, I can send you some digital photos of the
area you'd need to check.

Cheers,
Colin f

On Thursday 15 January 2004 22:20, Colin f wrote:
> If you go to the controller edit mode, the changing knobs
> will activate their step LEDs (cc is auto set active when
> the value is changed), so you should be able to see which
> other one it is.

Clever! 
It's step #9 that is also emiting signals.
Does this mean anything?

- Robert

> Is this already available (and I missed it), or future 
> stuff?

It's been on the TBI list for ages, but I've only just started working
on it recently.
A limited set of functions should appear soon, and then others will be
added as I'm pestered to do so by people who do too much thinking.

It means a change in the way the sequencer playback engine works, which
is why I've been putting it off.
Instead of processing each track in turn, it will have to load in the
current step data for all tracks in parallel.
Then any functions that modify the current step data based on other
tracks can read the relevant data for the other tracks, and modify the
current data for the track being modified. Then the data is all
transmitted.
I'll also add some other state variables for each track variables that
allow cumulative modifications.
e.g. 'transpose pattern relative +1' will add a semitone to the
'transpose accumulator' each time that step is played.
So you could set a pattern to move up a semitone at the first step, and
each time it loops, it will go up a semitone until it reaches the
transpose limit and wraps. This is a Notron inspired thing. But this
implementation should be more flexible.

Some examples of the planned functions are:

	grab note value from alternate track
	transpose by note from alternate track
(cv mixing anyone ? - multiple aux controllers doing this from multiple
source tracks will cumulatively transpose the current step so that all
the tracks involved are 'added')

	transpose pattern absolute	(+/- 48)
	transpose pattern relative	(+/- 48)
	set pattern length absolute (1 - 16)
	set pattern length relative (+/- 15)
(add 1 to the length of a pattern each time round, and it will play
steps 1, 1, 2, 1, 2, 3, 1, 2, 3, 4,... and so on)

	set global tempo
	set global FTS scale
	set global FTS root absolute
	set global FTS root relative

I'm sure there were other Nagle suggestions I've got written down
somewhere...

And in order to provide some randomness, there will be functions that
can be assigned to a controller to modify the value of another
controller or step data by a certain random amount, or to select whether
it takes effect or not based on a probability.

It may all sound very complicated, but you can ignore it if you don't
want to use it.
I think it will allow for all sorts of complex modulation of patterns,
most of which I probably haven't thought of yet.

Cheers,
Colin f

On Thursday 15 January 2004 22:26, Colin f wrote:

> The aux controller to 'transpose by track n', will allow
> you to have any other track's current note value 'added'
> to the note value for that step.
> So setting up a pattern on track 2, with 'transpose by
> track 1' on every step will give you this effect.
> Or you could use track 3 as the 'summed' track, and
> alternate between transposing from track 1 or 2, and do
> very weird stuff. Or use all 4 aux controllers to add up
> to 5 tracks together.

Is this already available (and I missed it), or future 
stuff?

- Robert

On Friday 16 January 2004 11:34, Colin f wrote:
> It means a change in the way the sequencer playback
> engine works, which is why I've been putting it off.
> Instead of processing each track in turn, it will have to
> load in the current step data for all tracks in parallel.

I understand.

> Then any functions that modify the current step data
> based on other tracks can read the relevant data for the
> other tracks, and modify the current data for the track
> being modified. Then the data is all transmitted.

But how do you account for different playback speeds (i.e. 
different step lengths)? Could be that step 1 on track 1 
modifies 8 steps on track 2, right? So you have to keep the 
current state of each track? That sounds like a major 
change indeed.

> I'll also add some other state variables for each track
> variables that allow cumulative modifications.
> e.g. 'transpose pattern relative +1' will add a semitone
> to the 'transpose accumulator' each time that step is
> played. So you could set a pattern to move up a semitone
> at the first step, and each time it loops, it will go up
> a semitone until it reaches the transpose limit and
> wraps. This is a Notron inspired thing. But this
> implementation should be more flexible.

Sounds great! :)

>
> Some examples of the planned functions are:
>
> 	grab note value from alternate track
> 	transpose by note from alternate track
> (cv mixing anyone ? - multiple aux controllers doing this
> from multiple source tracks will cumulatively transpose
> the current step so that all the tracks involved are
> 'added')
>
> 	transpose pattern absolute	(+/- 48)
> 	transpose pattern relative	(+/- 48)
> 	set pattern length absolute (1 - 16)
> 	set pattern length relative (+/- 15)
> (add 1 to the length of a pattern each time round, and it
> will play steps 1, 1, 2, 1, 2, 3, 1, 2, 3, 4,... and so
> on)
>
> 	set global tempo
> 	set global FTS scale
> 	set global FTS root absolute
> 	set global FTS root relative

Wow. Impressive!

>
> I'm sure there were other Nagle suggestions I've got
> written down somewhere...
>
> And in order to provide some randomness, there will be
> functions that can be assigned to a controller to modify
> the value of another controller or step data by a certain
> random amount, or to select whether it takes effect or
> not based on a probability.

I'm curious how all this beautiful stuff is offered on the 
user interface level. Doesn't sound easy at all.

- Robert

on 15-01-2004 20:29, Robert van der Kamp at robnet@wxs.nl wrote:

> I'll give that a try, tomorrow, if Boele is OK with it.

I am. just watched my mailbox at work :-))

Boele
>

> I'm curious how all this beautiful stuff is offered on the 
> user interface level. Doesn't sound easy at all.

The values for these controllers will be edited just the same as for
midi CCs now.
But I will probably add a text display to show what the current
controller selected is while you are editing it, so you can keep track
of what's going on.
Assigning the controllers to aux A, B, C or D will be the same as now,
except pressing the PAGE key will switch between midi CCs and the...
whatever I call them. I haven't really decided on the terminology yet.
Maybe aux functions.
Anyway, there is space to select from 128 different aux functions, and
the processing of each one will just sit in a huge case statement, so
once the basic framework is in place, it's easy to add a pile of them.
And they won't get in the way if you don't ever want to use them.

Cheers,
Colin f

On Friday 16 January 2004 00:27, Colin f wrote:
> > It's step #9 that is also emiting signals.
> > Does this mean anything?
>
> Interesting. Step 9 is input 0 on the 4051, step 13 is
> input 4. The tracks for these two run next to each other
> for a short distance - there could be a connection
> between them.
> But I think a bad 4051 is more likely.
> If Boele let's you open it up, I can send you some
> digital photos of the area you'd need to check.

Okay Colin, what do I do?

- Robert

> Okay Colin, what do I do?

Open the case by removing the 6 screws along the front and rear edge of
the base.
Lift the top part off by tilting it up on it's rear edge. You will need
to disconnect some of the cables to get the top to sit right back.
Then look at this photo:
http://www.colinfraser.com/p3/images/p3-005-inside.jpg
That's pretty much how the inside of Boele's should look.
The pot boards are the long thin ones connected to all the pots,
obviously.
There are only two ICs on the pot boards. Take the two on the upper pot
board out, and swap them over, making sure to put them into the sockets
pointing in the right direction. You might need a little scremdriver to
lever them out. Make sure to do it evenly at each end so the pins don't
get bent.

Cheers,
Colin f

On Saturday 17 January 2004 03:00, Colin f wrote:
> > Okay Colin, what do I do?
>
> Open the case by removing the 6 screws along the front
> and rear edge of the base.
> Lift the top part off by tilting it up on it's rear edge.
> You will need to disconnect some of the cables to get the
> top to sit right back. Then look at this photo:
> http://www.colinfraser.com/p3/images/p3-005-inside.jpg
> That's pretty much how the inside of Boele's should look.

Apart from some women's underware stuffed between the pot 
boards, it looked identical yes.

> The pot boards are the long thin ones connected to all
> the pots, obviously.
> There are only two ICs on the pot boards. Take the two on
> the upper pot board out, and swap them over, making sure
> to put them into the sockets pointing in the right
> direction. You might need a little scremdriver to lever
> them out. Make sure to do it evenly at each end so the
> pins don't get bent.

Okay, I removed the two ICs from the upper potboard (the one 
printed 'Upper potboard', with no luck. Then I also swapped 
the ICs on the lower board. No luck either. I get the same 
repeating events from step #13.

Are there other options?

- Robert

> Apart from some women's underware stuffed between the pot 
> boards, it looked identical yes.

I wondered where they'd gone...
 
> Okay, I removed the two ICs from the upper potboard (the one 
> printed 'Upper potboard', with no luck. Then I also swapped 
> the ICs on the lower board. No luck either. I get the same 
> repeating events from step #13.
> 
> Are there other options?

If moving the ICs leaves the problem in the same place, then the 
problem is either on the pot itself, or the PCB. Either could be 
affected by shock or dirt during shipping, although I would think it 
more likely the pot has the problem than the PCB.
How's your soldering ?
I can post you a couple of spare pots to try replacing them.
Until then, you could prove conclusively whether the pot is at fault 
by swapping pots on the same board.

Cheers,
Colin f

on 19-01-2004 12:38, Robert van der Kamp at robnet@wxs.nl wrote:

"Zucht..." That's Dutch for "Sigh..."

I *really* hope nothing serious is broken.

Boele

> On Saturday 17 January 2004 03:00, Colin f wrote:
>>> Okay Colin, what do I do?
>> 
>> Open the case by removing the 6 screws along the front
>> and rear edge of the base.
>> Lift the top part off by tilting it up on it's rear edge.
>> You will need to disconnect some of the cables to get the
>> top to sit right back. Then look at this photo:
>> http://www.colinfraser.com/p3/images/p3-005-inside.jpg
>> That's pretty much how the inside of Boele's should look.
> 
> Apart from some women's underware stuffed between the pot
> boards, it looked identical yes.
> 
>> The pot boards are the long thin ones connected to all
>> the pots, obviously.
>> There are only two ICs on the pot boards. Take the two on
>> the upper pot board out, and swap them over, making sure
>> to put them into the sockets pointing in the right
>> direction. You might need a little scremdriver to lever
>> them out. Make sure to do it evenly at each end so the
>> pins don't get bent.
> 
> Okay, I removed the two ICs from the upper potboard (the one
> printed 'Upper potboard', with no luck. Then I also swapped
> the ICs on the lower board. No luck either. I get the same
> repeating events from step #13.
> 
> Are there other options?
> 
> - Robert
> 
> 
> 
> 
> 
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On Monday 19 January 2004 13:56, colinfraser_com wrote:
> > Apart from some women's underware stuffed between the
> > pot boards, it looked identical yes.
>
> I wondered where they'd gone...

She looks nice. Say hello for me.

>
> > Okay, I removed the two ICs from the upper potboard
> > (the one printed 'Upper potboard', with no luck. Then I
> > also swapped the ICs on the lower board. No luck
> > either. I get the same repeating events from step #13.
> >
> > Are there other options?
>
> If moving the ICs leaves the problem in the same place,
> then the problem is either on the pot itself, or the PCB.

If it's the pot, we would have 2 bad pots now.  Both pot #9 
and #13 are still involved. Isn't it very unlikely to have 
two bad pots? 

> Either could be affected by shock or dirt during
> shipping, although I would think it more likely the pot
> has the problem than the PCB. How's your soldering ?

That's fine I guess. I'm building a MOTM modular system. Is 
that good enough?

> I can post you a couple of spare pots to try replacing
> them. Until then, you could prove conclusively whether
> the pot is at fault by swapping pots on the same board.

Okay, I'll try that. But before I do, I'll do the chip swap 
yet another time, just to be sure.

- Robert

Colin, what about bad flat cables? Do the signals of pot #9 
and #13 run next to each other in one of the cables?

- Robert

Or exchanging the pot boards, just as a test. Would that be 
possible? Beats soldering.

- Robert