> I have a couple of questions about the analogue outputs...
>
> Is there a Clock/start/stop CV option available?
I haven't implemented it, but there's no reason why the gate (or even CV)
outputs can't be configured to send clock.
But there is a dedicated DIN sync output already.
Or did you mean input ?
> The CV coming out of the DB25 cable what voltage range do they have?
> (0-10V, -5/+5V,...)
The CV range was 0 to 10.58 volts, but I'm going to change it.
The value of 10.58V came from the full MIDI note range. With note 0 = 0v,
and 1V/octave scaling, note 127 is at 127/12 volts = 10.58V.
There is a gain preset on the DAC buffer that allows this voltage to be set
precisely.
However, a couple of factors have changed my mind.
One is that not all 1V/octave synths agree on the size of 1V.
I thought that most people with multiple analogues would have the scaling
standardised across synths, but it was pointed out to me that even though
you can adjust the VCO scaling on every synth, some synths have no
adjustment on the scaling of their keyboard circuit, so the VCO has to be
scaled to suit the keyboard.
Also I've been asked by a few customers if it will support the Buchla
1.2V/octave standard, which I had previously never heard of.
That's 0.1V per semitone, which is a rather friendlier number than
0.083333...
To solve these issues, I have implemented independent scaling for each CV
output.
The DAC has 16-bit resolution, so it's a simple matter to store a 16-bit
scaling factor for each output, and adjust the CV values on the fly.
I will be adding a calibration routine to simplify setup, where you can
trigger a synth for one pitch, check the pitch with a tuner, then raise the
CV for a couple of octave increase and use an encoder on Cirklon to bring
the higher note into tune.
From the difference between the original CV and the adjusted octaves up CV,
Cirklon will be able to calculate the correct octave scaling for the synth.
For the purposes of supporting a Buchla CV input over 10 octaves, it
probably makes sense to set the DAC gain for slightly more than 12V
full-scale.
At some later date, I might even be persuaded to add micro-tuning tables.
> Same for the gates.
Gates are 5V for high-level.
I've just recently realised they may also be able to do S-trig natively -
assuming the non-shorted floating voltage on the S-trig input is in the
range of 0 to 5V.
It is on both my minimoog, and a Korg MS10 I've checked. I need to
investigate compatiblity with other S-trig synths.
> Is there a way to synchronize the cirklon to an LFO?
Not yet. Would you want to ? It likes to be the boss.
> Do I need a +/-15V (12V) PSU to power the break out PCB for
> the analogue outs?
> How many multiples (e.g. 1 in to 4 outs) can be connected to
> the output of the break out PCB?
The break-out is entirely passive, unless you want to add some custom
voltage alteration, such as shifting the CVs down to a bi-polar range, or
increasing the gate levels.
The number of multiples you could use will depend on the input impedances of
whatever you're driving.
The CV outputs are driven by TL062B op-amps, which are fairly typical.
> On the cirklon, can a track be assigned to multiple CV/gates out?
At the moment each CV output is assigned to a virtual MIDI channel on a 'CV'
port.
You can assign as many outputs as you like to the same channel.
When a track is assigned an instrument that sends to a channel on the CV
port, the CV outputs set to that channel will respond accordingly.
You can map the outputs to note, velocity or controller messages, with
normal or auto-glide.
I'm going to add the ability to mix variable levels of each source into a
single CV.
My minimoog has a VCO input and a filter input, and it doesn't do filter
tracking on the VCO input.
So I want my filter CV to be a mix of note (for key tracking), velocity and
a CC.
I have looked at adding specific aux events to achieve finer resolution
control over the CV outputs, but in practice I'm not finding I need that
level of precision in setting a step value.
The glide option on the CV outputs will smooth the transitions from one step
value to another in a P3 pattern, and that uses the full 16-bit resolution.
Best regards,
Colin Fraser
Sequentix Music Systems Ltd
http://www.sequentix.com