200e

well, it's a little complicated...

> OK, now here's something I don't understand: are the pots on the 250e
> specifying the voltages at runtime, or are they just a 'convenience'
> method for entering values into some internal memory?

you could say that the second case is true, in that there is a
computer in there with realtime memory. in the 250e, it is
continuously updating this realtime memory (and the cv output) based
on the knob position of the *current stage,* or based on something
else like an external cv input if it's in that mode.

What I am
> getting at is the following: suppose I use the pots to make a very
> basic CV sequence for output A with just the default values for
> everything else. If I then power cycle the unit without touching the
> pots and press start, will the sequence still 'be there' (after all,
> the pots haven't moved). Or would I have to wiggle each one again to
> 're-enter' the value into the memory?

the current behavior of the 250e is that it's supposed to read the
physical knob positions when it powers up, but it's slightly buggy
because of a conflict with the interpolation algorithm (which i'll get
to in a second) and because the knobs aren't all scanned at once but
rather at each stage of the sequence (which allows each knob to be
scanned at a much faster update rate). so it's tricky, and right now
the accuracy at startup depends on the difference between the stored
values and the phyiscal values. one of our programmers is working very
hard on making it better. at the moment i'm afraid the best way to get
consistent behavior is to use the thing in conjunction with a 225.
it's somewhat of a trade-off, but i personally consider it more
convenient than old drifty analog sequencers.

a behavior that i maybe like better is to have the 250e alwasy load
preset zero at startup, so you can have some control over the
"default" behavior, and to make it amenable to the autonomous preset
storage behavior that we implemented in the 210, 291 and others. even
this is kind of difficult because of the realtime updating that i
mentioned before, but fixing it is a high priority.

> This makes me think of a more general problem with discrepancy between
> pot positions and stored values in the 200e as a whole: how is the
> conflict resolved? If you touch a knob after loading a preset, does
> the value jump to the new pot position, or is there a 'latch' mode
> like on some other synths (not sure which is better / worse, I don't
> really like either)?

neither do we. the 259e was the first module in the series and it used
a latch, but don has since designed a quite elegant algorithm to
smoothly interpolate between the physical knob positions and the
stored parameter values at all times. basically the knob range is
rescaled until its position matches the stored position, at which
point it resumes its default scaling with no perceivable transition.
this is true for nrealy all of the knobs in the system.

> Is there a way to force a module to use its front panel settings
> rather than whatever is stored in patch memory (I can imagine, for
> example, pressing and holding 'remote enable' for a few seconds, to
> toggle between the front panel values and the stored values).

that's a nice idea. the remote enable button is already overloaded but
it's a nice idea. currently you can make sure you are reading the full
range of each knob by sweeping it between its extremes.

forcing each module to re-scan its panel with a switch might be cool,
but it also might be less useful than you think. the patch recall is
really kind of magical, and all knobs always respond smoothly and
pretty much as expected.

> Sorry for all these questions, I just want to make sure I order
> exactly what I need. By the way, quantization doesn't really bother
> me: many of my other analogue sequencers don't even have it. As long
> as you can adjust the sequencer CV's finely enough to hit the sweet
> spot, I don't care.

cool. accurate pitch is of course a crucial and difficult problem
because of the incredible resolution of the ear in the frequency
domain. the buchla solution has always been to allow arbitrary scaling
of frequency modulators. this means that it is possible to trade range
for accuracy at will, or vice versa. i think it is still a good system
that works quite well, and has managed to accomodate a wide variety of
technical limitations and tolerances in the last 35 years.

i might as well freely admit that the 250e is not an analog sequencer,
it has a digital brain and an analog-style interface layer. in some
respects its character is noticeable, but in other respects it kind of
transcends such discriminations with a truly freaky set of
capabilities...

> Thanks a lot!

no prob

-eb

> --- In 200e@yahoogroups.com, "ezra buchla" <ezra.buchla@...> wrote:
>>
>> that's right. getting autonomous preset storage in the 250e is a
>> priority but it's proven difficult. next firmware rev.
>>
>> fort now, you must use a 225.
>>
>> On Wed, Aug 20, 2008 at 1:24 AM, JB <ringmodulator@...> wrote:
>> > This is something i know Ezra has been working on implementing in all
>> > modules, but im not sure if the 250 has this feature yet. I would
>> > recommend getting the 225e though, being able to switch presets is
>> > very valuable if you plan to use the system live, its a great feature,
>> > i use it all the time.
>> >
>> > 2008/8/20 kkonkkrete <kkonkkrete@...>:
>> >
>> >>
>> >> How much does the Arbitrary Function Generator remember at power
> down?
>> >> If you don't have a 225e to store the settings, does the 250e recall
>> >> all data for the current settings, or do you have to reprogram it
>> >> every time you power up (or load the program from the 225e if you
> have
>> >> one)?
>> >>
>> >> Sorry for this basic question ...
>> >>
>> >> Thanks,
>> >> KKonkkrete
>> >>
>> >>
>> >> ------------------------------------
>> >>
>> >> Yahoo! Groups Links
>> >>
>> >>
>> >>
>> >>
>> >
>> >
>>
>
>