Klavis - CalTrans

[Zentek]

The Klavis CalTrans is now appearing in shops.
Preorder it if your preferred retailer doesn't have it yet.



CalTrans is a quad V/Oct calibrator with presets and direct access to semitones and octave transposing. The MSRP is USD179,- / 159€

The goal is to have up to 4 VCOs (or would be VCOs ) playing in tune and be transposed easily in live situations.


Here are the full specs:

Four channel, each with independent:
- V/Oct in
- V/Oct out
- Auto calibration of anything that somehow oscillates : hihi:
- Octave setting via dedicated rotary click encoder
- Semitone setting via dedicated rotary click encoder
- Semitone quantizer on/off
- Portamento duration
- Glissando duration

Besides calibration which is only done once (but separately) for the 4 VCOs, there are 4 user presets for all the other settings.

More than one channel can be applied a setting/transpose at once by selecting multiple channels jointly.
This is especially useful for playing polyphonic as there's no need to replicate settings.

When the built-in quantizer is not used, the incoming V/Oct CV is respected as is, but curve-corrected anyway (it will convey whatever glide, vibrato, .. you've added).

There are two encoders for instant access to octaves and semitones adjustment.

There is no need to replicate a CV to several inputs; this happens automatically with zero impact on the load (avoids affecting the pitch precision).
This way a single melody CV can drive a chord without drift.

When several channels are transposed, the ones that cannot follow (too high, too low) will be maintained at the right note (degree) within the last octave they can play. This way, the harmony is not broken.

Calibration is not only for actual VCOs; even a Maths that is definitely not V/Oct compliant (and requires negative voltages to rise its pitch!) can play perfectly in V/Oct via the CalTrans

The module is 6hp and uses no 5V


The 3 minutes video for those in a hurry:
[video][/video]

The detailed video for the connoisseur:
[video][/video]

Thanks for your interest.

[williamjturkel]

Klavis modules are so clever. Now I need one of these!

By the way, if you are looking for ideas for future projects, please make a 16hp 4x4 matrix mixer using the same knob and switch arrangement you used for Mixwitch. I need one for each of my cases.

[meatbeatz]

Exactly what I was looking for!

[Nino]

[davidjames]

I'm all over this! I wonder how well it will work with Rings. Love my Rings. Hate tuning my Rings.

Also, it would be great if you could simply turn VCO coarse tuning full CCW before calibrating. Then there would be no risk of bumping it out of tune during a set. From the video it looks like you cannot do that. Maybe a firmware update?

[milleborne]

need this to get all my vintage synths to play nice with my modular vco's

[pre55ure]

Looks like a really useful module.

As a Californian, the name weirds me out a bit. (We have a Caltrans here too!)

[Zentek]

I'm all over this! I wonder how well it will work with Rings. Love my Rings. Hate tuning my Rings.

As a resonator requiring a trigger, Rings is not providing a continuous sound. Also, all it generates contains more than one fundamental tone :-(

Also, it would be great if you could simply turn VCO coarse tuning full CCW before calibrating. Then there would be no risk of bumping it out of tune during a set. From the video, it looks like you cannot do that. Maybe a firmware update?

Depending on the oscillator, doing so will generally be ok.
It could be restricting for VCOs whose voltage span at V/Oct input is not wide enough. In such a case, you may possibly not reach the high pitched notes you may want to play. Only in that case, you'll have to tune the coarse knob a bit higher.
This is why the manual recommends setting the coarse to the lowest note you expect playing (instead of a possible sub-audio setting when fully CCW)
The limit is in some VCOs not in the CalTrans hardware or software.

Thanks for the feedback.

[Zentek]

Looks like a really useful module.

As a Californian, the name weirds me out a bit. (We have a Caltrans here too!)

Thanks for the
I've been in California enough times to know that CalTrans too
Since the name does not carry anything inappropriate, I thought it might be a good trick to make people not forget the name of my module even after seeing it once!
Just weird enough to remember without being too silly.

[davidjames]

As a resonator requiring a trigger, Rings is not providing a continuous sound. Also, all it generates contains more than one fundamental tone :-(

That makes sense, as I always struggle to find a Rings tone that works with my external tuner. In the manual it mentions omitting calibration, so could I just use this module to handle transposition on Rings along with my other voices? Would I then have to skip calibration for those other voices as well, or could I calibrate 3 VCOs and use the fourth channel, uncalibrated, to control Rings?
Luckily, Rings is not always in my live case

[Zentek]

...
Would I then have to skip calibration for those other voices as well, or could I calibrate 3 VCOs and use the fourth channel, uncalibrated, to control Rings?

Yes, this could be done the way you describe.
I would, however, calibrate that fourth channel with some "known-good" VCO first, so that at least the transpositions on Rings are ok (if Rings follows V/Oct well by default)

[Agawell]

Hi Zentek

looks great!

it's not too clear from the video or the description, but can the CalTrans do this:

take up to 4 v/oct inputs and transpose them via a 5th v/oct input

for example: the 3 v/oct outputs from marbles and 1 from a bsp and then transpose those sequences with the 2nd bsp sequencer channel

if it can then it'll definitely be one of my next 2 bought modules (but mostly diy at the moment!!)

[Zymos]

Rings are the easiest to tune modules I own, being quantized. You just need to dial down the overtones. If you are really having trouble, maybe it needs to be calibrated?

[Zentek]

...
it's not too clear from the video or the description, but can the CalTrans do this:
take up to 4 v/oct inputs and transpose them via a 5th v/oct input

There are only 4 V/Oct inputs in total. You'll have to make such summing separately.

[Zentek]

Rings are the easiest to tune modules I own, being quantized. You just need to dial down the overtones.

I had no opportunity to try. Good news then!
Thanks for the info.

[Zentek]

I got a question by mail that also needs a public explanation:
"Can you allocate a channel to control various VCOs as needed?"

Yes, but with some constraints and restrictions.
First, you have to calibrate that channel with a trusty VCO.
Most digital VCOs will do fine in that respect.

As long as the VCOs you swap on a given CalTrans output are "reasonably" following V/Oct, things should be fine.
The more these VCOs are away from an ideal V/Oct curve the more inaccurate the tracking will be with one or another.

Keep in mind that there is another bit of information that the CalTrans makes use of: the first and last reachable note that plays in tune for each channel. This is identified during the calibration procedure.
This info is used to keep a melody in tune when asking to transpose beyond/below those limits: the CalTrans will reposition the CV within the closest octave while keeping the degree (= name of the note).
By swapping VCOs on a given channel, that limit info is unusable and the feature will not work as it should.

This is why the ideal scenario is to allocate one CalTrans channel to a given VCO and leave it connected permanently. That CalTrans input channel becomes the default V/Oct input of the attached VCO.

[Nino]

edit: question obsolete, ordered

[Agawell]

...
it's not too clear from the video or the description, but can the CalTrans do this:
take up to 4 v/oct inputs and transpose them via a 5th v/oct input

There are only 4 V/Oct inputs in total. You'll have to make such summing separately.

in that case would it be possible to use one of the v/oct input for transposing - maybe a firmware update - would be really useful - much more practical than having 3 or more precision adders in the case

[Zymos]

^ that would make this a must buy for me!

Though I'm seriously considering it anyway...

[mosorensen]

+1 for using a v/oct input for transposing. That would be awesome.

[paperCUT]

I've spent quite a few hours now with the Caltrans, really great module that does it's job well! A few questions regarding calibration, the manual states the green led should be full on when calibration is completed, mine hasn't ever gone full on and in the video above it doesn't seem to either. Is that just a typo?

I'm slowly testing all my modules and couldn't get the Synchrodyne to register any low octaves. I know this tracks pretty much perfect across it's 20+ octaves so I don't know what's up with that oscillator. Maybe the calibration prefers upper registers? I got all 4 VCOs in A-143-4 pretty much rock solid over the full range. They tend to drift but track very well and sound rather large panned all over

I haven't found a way to disable the calibration once it's done and it's not mentioned in the manual.

A few requests if new features are possible:
More presets! The interface is just fantastic for switching presets, and the results are beautiful. Could you possibly add voltage controlled preset selection? That would take this to another level.

The range of Glissando seems to be extremely touchy compared to portamento, it feels like it should come on more exponentially.

The idea of transposing using a spare V/oct in is great.

And one bug has been happening, when switching presets VERY rarely there is subtle HF noise on random channels. It seems to only affect one or 2 at a time. I'll try get a recording, it usually lasts a second or 2 and doesn't seem like a hardware bug since I've only noticed when switching presets.

If you're on the fence about getting one it's a no brainer. Forget about calibration, quantizing, presets, semitones, glissando....Just getting 4 octave switchers with glide would justify the money and space

[Zentek]

I've spent quite a few hours now with the Caltrans, really great module that does it's job well! A few questions regarding calibration, the manual states the green led should be full on when calibration is completed, mine hasn't ever gone full on and in the video above it doesn't seem to either. Is that just a typo?

Thanks for spotting it! That's a typo sort of.
In the prototype the calibration LED was green. The text should now mention a blue LED!

I'm slowly testing all my modules and couldn't get the Synchrodyne to register any low octaves. I know this tracks pretty much perfect across it's 20+ octaves so I don't know what's up with that oscillator. Maybe the calibration prefers upper registers?

Do you have any means of grabbing a visual of the wave shape (oscilloscope, real or phone/pc based app)? I would be very curious to know more. This can follow up in mp.

I got all 4 VCOs in A-143-4 pretty much rock solid over the full range. They tend to drift but track very well and sound rather large panned all over

yep this is a good combo.

I haven't found a way to disable the calibration once it's done and it's not mentioned in the manual.

No calibration is still "some" calibration. Maybe you refer to a default neutral calibration? Every oscillator, even the most perfect ones, have their subtle nuance in the curve. So, making the CalTrans comply to their tracking is the only way to have the 4 channels behave in a predictable way.
Another feature that would be lost without calibration is the end-of-scale detection used to transpose musically. This allows any VCO to be transposed freely even if some are not able to follow the others as high or low as the widest ones.
This explain why we skipped this "neutral" calibration possibility.
We also wanted to avoid the arguments about "My wonder VCO tracking disagrees with the CalTrans while it should perfect; how is that?"

A few requests if new features are possible:
More presets! The interface is just fantastic for switching presets, and the results are beautiful. Could you possibly add voltage controlled preset selection? That would take this to another level.

It is difficult to add functionalities without the risk of making the interface cryptic. We should think about that aspect because the idea is indeed very nice.

The range of Glissando seems to be extremely touchy compared to portamento, it feels like it should come on more exponentially.

Something to fine tune on our side apparently.

The idea of transposing using a spare V/oct in is great.

Yep. We took note already.

And one bug has been happening, when switching presets VERY rarely there is subtle HF noise on random channels. It seems to only affect one or 2 at a time. I'll try get a recording, it usually lasts a second or 2 and doesn't seem like a hardware bug since I've only noticed when switching presets.

You are the first to report that behavior. We should investigate ...
I'll be back to you if nothing shows here.

If you're on the fence about getting one it's a no brainer. Forget about calibration, quantizing, presets, semitones, glissando....Just getting 4 octave switchers with glide would justify the money and space

[sir stony]

I don't think trying to squeeze many more modes and options into this wonderful module is a great idea. If it had a few more ways of visual feedback like a display or a couple more leds, ok.

But it's really a great module already, as it is, and for a reasonable price considering the hours of unavoidable tuning work saved over a couple of years of use. If people need precision adders and cv'able transposers, there are other modules to do that, thinking e.g. vpme t43 and frequency central transeuropa. They are good, but not everyone needs them, and modules that are overstuffed with features and too little visual feedback about what's going on are a sure call for chaos to get lost in, and nobody is a fan of that, right?

I'd prefer to leave the caltrans as it is, nice and slim, but maybe make a bigger brother to it which incorporates such extras, also maybe all the different scales that are in the twin waves, too? Looking at the the µO_C, it wouldn't even have to be any bigger than that.

[Riggar]

sir stony said - 'I don't think trying to squeeze many more modes and options into this wonderful module is a great idea'


+1

[NS4W]

So no matter what base frequencies you tune the the oscillators and calibrate them via Caltrans, all will play for example a C-note if I send Caltrans a C-note CV from my MIDI-CV keyboard?