Doepfer

Hi everyone, been reading for a while, but cos I never actually owned any
Doepfer modules, I didnt have much to say, except Hello. Im glad to report
that this has now changed as I have purchased 11 modules secondhand, and
intend on buying LOTS MORE!!!
I have 2 completely unrelated questions, one about a module I now own, and
one about a module I am lusting after!!!

One concerns the A155 sequencer, that I am having alot of fun with, BUT...
am i right in thinking that I should patch the glide socket into a trigger
row to control which beats get glide... if no patch then ALL beats glide??
COs that aint working for me, am I doing something wrong? Same goes for the
S & H socket, although this maybe my confused mind, this sockety seems
complex in what it does, anyway, somthing odd happens when I patch it to a
trigger, but not quite what I expected.

Secondly, I want to get the A112 sampler, but need some clarification on
some things. I find it strange that the audio IN socket is also the wave CV
in.
Does this imply a frantic unplugging of cables mid performance to first
record a sample/wave and then jump about in it??? And secondly is it a shame
that the rec/play function is not triggerable? I would have thought much fun
could be derived from auto grabbing audio (say voice) and then immediately
sequencing it, this could be possible by making these functions trigger-able
externally. Im imagining of all sorts of wonderful glitchy (almost granular
***) madness here.
Maybe Im not quite getting how this thing works, Im sure ill get one anyhow,
just like to whet my appitite while I save my pennies!!!

Looking forward to some crazy modular madness!!!

ps Are list users posting mp3s anywhere??

regards Mark

***(how about a granular module Dieter? As far as I know there has never
been a hardware granular synth)


-- 
www.markfrancombe.com
www.looop.no


[Non-text portions of this message have been removed]

Mark,

you find my comments written inline.

Best wishes
Dieter Doepfer

> Hi everyone, been reading for a while, but cos I never actually owned any
> Doepfer modules, I didnt have much to say, except Hello. Im glad to report
> that this has now changed as I have purchased 11 modules secondhand, and
> intend on buying LOTS MORE!!!
> I have 2 completely unrelated questions, one about a module I now own, and
> one about a module I am lusting after!!!
>
> One concerns the A155 sequencer, that I am having alot of fun with, BUT...
> am i right in thinking that I should patch the glide socket into a trigger
> row to control which beats get glide... if no patch then ALL beats glide??
> COs that aint working for me, am I doing something wrong? Same
> goes for the
> S & H socket, although this maybe my confused mind, this sockety seems
> complex in what it does, anyway, somthing odd happens when I patch it to a
> trigger, but not quite what I expected.

trigger signals are very short pulses only. But if you want to control e.g.
the glide or S&H you need a constant level of the control voltage over the
complete step duration. Consequently trigger signals are not suitable to
control glide or S&H of the A-155 sequencer. You have to use gate signals
instead of trigger signals.

> Secondly, I want to get the A112 sampler, but need some clarification on
> some things. I find it strange that the audio IN socket is also the wave
CV in.

To control the wavetable number you need an additional CV during play back
(i.e. in addition to the pitch CV). During playback to Audio In socket is
not required and can be "abused" for this function.

> Does this imply a frantic unplugging of cables mid performance to first
> record a sample/wave and then jump about in it??? And secondly is it a
shame
> that the rec/play function is not triggerable?

The module can can modified for this function. In principle all switch
functions can be controlled by voltages as the three position switches
generate internally nothing but 0V/+2.5V/+5V.

> I would have thought much fun could be derived from auto grabbing audio
(say voice) and then immediately
> sequencing it, this could be possible by making these functions
trigger-able
> externally. Im imagining of all sorts of wonderful glitchy (almost
granular ***) madness here.
> Maybe Im not quite getting how this thing works, Im sure ill get one
anyhow,

> just like to whet my appitite while I save my pennies!!!
>
> Looking forward to some crazy modular madness!!!
>
> ps Are list users posting mp3s anywhere??
>
> regards Mark
>
> ***(how about a granular module Dieter? As far as I know there has never
> been a hardware granular synth)
>
> --
> www.markfrancombe.com
> www.looop.no

> The module can can modified for this function. In principle all switch
> functions can be controlled by voltages as the three position switches
> generate internally nothing but 0V/+2.5V/+5V.

dieter, could you publish information on how to do this? i am also
using  an a112 for live sampling and looping. operating the rec/play
switch with the same sequencer setup that provides the gates/triggers
would make life on stage with this module a lot more relaxed. 

another great help would be separate inputs for the recording gate and
the playback triggers - at the moment i have to manually reroute the
cable. can this be hacked?

one last question. would it mean a lot of work to increase the amount
of memory? i'm sure these days the cost would be of little
consequence, and at 32khz the memory is very short. i have the
impression that the module was conceived firstly as a wavetable
oscillator, but its sampling option really is a lot of fun.

i have a cheapo four track looper on stage with me, which i would
dearly love to replace by four a112's, and controlling the rec/play
switch by cv would bring me a lot closer :)

stu

> Mark,
> 
> you find my comments written inline.

Thanks!!

> trigger signals are very short pulses only. But if you want to
control e.g.
> the glide or S&H you need a constant level of the control voltage
over the
> complete step duration. Consequently trigger signals are not suitable to
> control glide or S&H of the A-155 sequencer. You have to use gate
signals
> instead of trigger signals.

OK .geddit... will try tonight, but thru weird experimentation i
discovered that by using a trigger on the glide (not gate) you CAN
control the glide, however its the oposite to what you wpould expect,
IE: A selected trigger going to the glide socket actually CANCELS a
glide for that beat... not activates it!!!

mark

> OK .geddit... will try tonight, but thru weird experimentation i
> discovered that by using a trigger on the glide (not gate) you CAN
> control the glide, however its the oposite to what you wpould expect,
> IE: A selected trigger going to the glide socket actually CANCELS a
> glide for that beat... not activates it!!!
>
> mark

Please look at the A-155 user's manual on page 8:


Glide Ctrl. :

The glide function is active whenever
the control signal input here is “low”.
H: If nothing’s connected to the
socket, glide function is active!

S&H Ctrl. :

This is the socket for the digital
Sample & Hold control input.
Whenever a "high" control signal is
sensed, the analog CV output is held
at the same level until the control signal
goes low. Usually one of the trigger
rows would be patched in to this
socket.

Dieter

> > The module can can modified for this function. In principle all switch
> > functions can be controlled by voltages as the three position switches
> > generate internally nothing but 0V/+2.5V/+5V.
>
> dieter, could you publish information on how to do this? i am also
> using an a112 for live sampling and looping. operating the rec/play
> switch with the same sequencer setup that provides the gates/triggers
> would make life on stage with this module a lot more relaxed.

It's very simple. The center pin of each switch is connected to an ADC pin
of the microcontroller. In the center position the voltage generated by the
switch is ~ 2.5V (nothing but a voltage divider made with two resistors
connected to +5V and GND). In the left/right position the terminal is
connected to +5V or GND. If you apply a voltage in the range 0...+5V to the
center pin of a switch (and make sure that the switch is in the center
position) you can switch between the 3 function with an external voltage.
But you have to pay attention that no negative voltage and no voltage beyond
+5V is applied. In this case the microcontroller will be damaged. Protection
diodes connected to GND and +5V in combination with a serial resistor (~1k)
should be sufficient.

> another great help would be separate inputs for the recording gate and
> the playback triggers - at the moment i have to manually reroute the
> cable. can this be hacked?

That's not possible without substantial hardware and software modifications.
Probably another microcontroller would be necessary as all pins of the
existing controller are in use.

> one last question. would it mean a lot of work to increase the amount
> of memory? i'm sure these days the cost would be of little
> consequence, and at 32khz the memory is very short. i have the
> impression that the module was conceived firstly as a wavetable
> oscillator, but its sampling option really is a lot of fun.

Even this would require a complete redesign as the microcontroller has only
16 addresses (A0...A15) available. RAM circuits with more memory are
available (the A-112 was developed ~ 10 years ago) but not pin compatible
with the chip used in the A-112.

We discussed several times if the sampler should be redesigned but after all
it requires the same development time as a totally new module (and we have a
lot of new modules in the waiting loop that would have to be postponed for
the benefit of a redesign).


Best wishes
Dieter Doepfer

This might help:

You could also do this with modules.
the Voltage Controlled Switch A-150 is tiny and you would still have a switch left over for other use.
Using a gate or other CV you could select between your wavetable CV or your audio signal to be recorded, both of which would be inserted to the A150.

Tony

>
>> another great help would be separate inputs for the recording gate and
>> the playback triggers - at the moment i have to manually reroute the
>> cable. can this be hacked?
>
> That's not possible without substantial hardware and software modifications.
> Probably another microcontroller would be necessary as all pins of the
> existing controller are in use.
>



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thanks dieter. it remains to be seen whether i find the courage to
start pumping hacked voltages into the newest module in my rack :)

> It's very simple. The center pin of each switch is connected to an
ADC pin
> of the microcontroller. In the center position the voltage generated
by the
> switch is ~ 2.5V (nothing but a voltage divider made with two resistors
> connected to +5V and GND). In the left/right position the terminal is
> connected to +5V or GND. If you apply a voltage in the range 0...+5V
to the
> center pin of a switch (and make sure that the switch is in the center
> position) you can switch between the 3 function with an external
voltage.
> But you have to pay attention that no negative voltage and no
voltage beyond
> +5V is applied. In this case the microcontroller will be damaged.
Protection
> diodes connected to GND and +5V in combination with a serial
resistor (~1k)
> should be sufficient.

am i right to assume that a diode has no value that needs to be
correct - any old diode from conrad will do?

thanks, stu

> am i right to assume that a diode has no value that needs to be
> correct - any old diode from conrad will do?
>
> thanks, stu

I'd recommend a Schottky type as these have a smaller forward voltage (e.g.
BAT42).

Best wishes
Dieter Doepfer