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[NEW] Serge NTO ... now for eurorack, too ...
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Author [NEW] Serge NTO ... now for eurorack, too ...
nordlead
It was quite a ride and it took longer than anticipated, but the Serge New Timbral Oscillator (NTO) is now also availble as a SMT-kit for eurorack - under license and in cooperation with Serge:



More info: http://randomsource.net/serge_euro

Some sounds:

[s]http://soundcloud.com/random-source/serge-nto-sequenced[/s]

[bandcamp width=100% height=120 track=561280880 size=large bgcol=ffffff linkcol=0687f5 tracklist=false artwork=small]
pritzcobinger
this is so good! Can't wait to build this thing!
cane creek
ordered we're not worthy applause
pix
fantastic! Will there be unpopulated PCB/panel kits available at some point?
Jarno
Nice work!

What is Serge thinking of all of that eurorack malarkey? Is he enthousiastic, maybe uses eurorack himself, thrilled that his circuits are well appreciated?
Was it nice working with him?
GryphonP3
we're not worthy does this mean we can expect a La Bestia II run soon? Guinness ftw!
pre55ure
GryphonP3 wrote:
we're not worthy does this mean we can expect a La Bestia II run soon? Guinness ftw!


I think it's up already?

Or at least the Deposit was.

Edit:
Here ya go - https://www.muffwiggler.com/forum/viewtopic.php?t=178514
nordlead
Many thanks for your comments and feedback, guys!

Guinness ftw! Guinness ftw! Guinness ftw!

Yes, La Bestia II is around the corner - pre-order phase started about a week ago and will probably close in about a week...
DJMaytag
Could you clarify this, regarding the exponential FM pot value:

Quote:
value determines knob sensitivity in the center (range is always the same)

What exactly does a higher pot value do here? Is it less sensitive with higher values? That's what would be intuitive to me, but I want to be sure before I start ordering parts I don't normally use (I don't think I've run across a single project that calls for that particular type of 9mm Alpha pot in anything higher than 100k).
nordlead
DJMaytag wrote:
Could you clarify this, regarding the exponential FM pot value...


The pot value affects the taper of the pot, B50K and B100K work fine, too. You can simply try this out (without soldering by sticking the pot in) before you mount the front panel.
gruebleengourd
What is the purpose of the optional 470n / 1 uF capacitor?
woodster
gruebleengourd wrote:
What is the purpose of the optional 470n / 1 uF capacitor?


Have a look at page 5 of the build guide -

'This capacitor is to remove any DC offsets from the signal
going into the (black) Linear FM input. It is in parallel to a 100n C0G cap already installed (increasing a
470nF cap effectively to 570nF), so even if you do not install the additional film cap, the LIN FM should
still work. The size of this cap (combination) affects the behavior of (very) low frequency signals going in,
however, there is another capacitor later in the audio path, so the effect is limited. Also, for normal audio
rates, it should not make much or any difference, only if you use frequencies like 20Hz. So no need to
worry about the size of this cap much. 470nF should work fine.'
taichber
Just “built” the 3U Serge NTO (quit simple, only a few trimmers, 1 capacitor and the hardware).

It sounds wonderful. I like especially the linear FM sounds :-)

But I have an issue with the calibration of 1V/OCT.
I followed the steps in the build doc (started with the lowest oven temperature).
I started with C1 (used MI Yarns as CV source) and then C2, etc.
The NTO does not track properly.
I tried several trimmer settings (used a single turn trimmer). I can’t find a setting which works.

Any recommendations for the calibration process?

Any recommended starting point? How should the frequency course and fine pot be set at the beginning of the procedure?

Did anyone build and calibrate already the NTO?
nordlead
taichber wrote:

Any recommendations for the calibration process?

Any recommended starting point? How should the frequency course and fine pot be set at the beginning of the procedure?

Did anyone build and calibrate already the NTO?


I've built and calibrated 2 of the Euro production series without any problems - I believe Dr Wiener built 4 and had no problems calibrating.

Some tips for 1V/Oct calibration: I'd recommend to use a keyboard with CV out. Turn the oven down and start not too low and not too high, eg. set the pitch to 220Hz or 110Hz (= A) using Coarse and Fine when playing a corresponding A on the keyboard. Then play 2 notes that are 1 octave or 2 octaves apart (i.e. let the control voltage jump exactly 1V or 2V). Use a tuner to see the pitch change, in particular if the jump in pitch is

- more than 1 octave (2 octaves if using 2V) => tracking is too steep; or
- less than 1 (or 2) octave(s) => tracking is too flat.

Then change the 1V/Oct trimmer (you hear a change in pitch - turn so that the pitch goes up if tracking was too steep and vice versa) and check again. You can also do this by ear till you can hear that you are close to or exactly at 1 octave per 1 octave of the keyboard. Using a single-turn trimmer makes it easier to find that point (but maybe a bit harder to set it very precisely if you're ambitious).

If you feel like you can't get to that region, first check the CV you actually send into the NTO to make sure that you really have a 1.0(0) Volt jump - otherwise any calibration efforts will be in vain. Also check that the 1V/Oct trimmer is the right size (100 Ohm = 100R). Finally you can check the actual range you get at each end of the trimmer - that should be more than 1 octave at one end and less than 1 octave at the other extreme. Beware that any changes in oven temperature affect the tracking, too, so don't touch the TEMP trimmer at all during this or you have to start from step 1.

Do not use very low frequencies (as the tracking gets uneven if the frequency is very low) and also avoid high frequencies (to reduce the influence of HF compensation and more importantly, some tuners (software, e.g. in logic) seem to have difficulties measuring precisely at high frequencies, like 2kHz and above). If you follow this and still can't find that sweet spot, send me an email...
taichber
nordlead wrote:


Some tips for 1V/Oct calibration: I'd recommend to use a keyboard with CV out. Turn the oven down and start not too low and not too high, eg. set the pitch to 220Hz or 110Hz (= A) using Coarse and Fine when playing a corresponding A on the keyboard. Then play 2 notes that are 1 octave or 2 octaves apart (i.e. let the control voltage jump exactly 1V or 2V). Use a tuner to see the pitch change, in particular if the jump in pitch is

- more than 1 octave (2 octaves if using 2V) => tracking is too steep; or
- less than 1 (or 2) octave(s) => tracking is too flat.


Thanks Ralf! Was my problem with the calibration procedure...

Just calibrated with your tipps. Now the NTO works perfectly!
dksynth
How could I increase the max Portamento amount? I have built two and it is quite tame at max settings. I want looooooong slides.
sockmonkey
Hey there -- Just built mine using 100K pots. Everything works, but the portamento amount is a) pretty low and b) only starts kicking in at about 50% on the pot. Any thoughts on that?

Thanks! Jeremy

EDIT: if I feed a constant voltage into the CV input, the pot works nicely across the whole range, so it seems like either everything is correct, or something else is up.

The sync input doesn't really work like any Sync I've ever used. (Actually it does, it just doesn't work with the pulse output of the DPO for some reason. With a Dixie it works fine. Go figure.)

Also did anyone else have issues with soldering pretty much anything connected to ground? The solder didn't want to stick to the pads.
ludotex
sockmonkey wrote:


Also did anyone else have issues with soldering pretty much anything connected to ground? The solder didn't want to stick to the pads.


I had sometimes the problem, I think maybe it's because the pads are small, and so it's harder to heat them. After I made sure that my iron was closer to get more heat it was better.

Mine works great, the vari output is awesome, so is the FM. And yeah the portamento is a bit weird at first but with VC signal in its longer (details about this need investigation though).

I really like that there is a lot of inputs that beg to be modulated. I put the vari output before the wave multiplier and it was nice and rubbery.

The only thing I was wondering is why the output is a bit lower in volume than my other VCOs. I compared to the DUSG in saw mode and the Dixie saw, and both were a bit louder than the NTO (like maybe a quarter/third of the perceived volume).

Anyway, loving it. I'll try to post some videos sometimes so people get more sources to listen to.
gruebleengourd
sockmonkey wrote:

Also did anyone else have issues with soldering pretty much anything connected to ground? The solder didn't want to stick to the pads.


I've noticed this is a a general thing with the RS modules. Big ground planes are common and they will absorb a lot of heat. I pre apply no clean flux to all the holes/legs.
Permette
sockmonkey wrote:
Also did anyone else have issues with soldering pretty much anything connected to ground? The solder didn't want to stick to the pads.


Yes, also, and that turned me into craziness and stress but it ends out to work perfectly smile
Triglav
I've just built mine, works and sounds great!
Does anyone know the reasoning behind the separate 1v/oct and Portamento inputs? Why would I use the 1v/oct if I can just set the portamento to 0?
nordlead
Triglav wrote:
I've just built mine, works and sounds great!

Rockin' Banana! Rockin' Banana! Rockin' Banana!

Triglav wrote:
Does anyone know the reasoning behind the separate 1v/oct and Portamento inputs? Why would I use the 1v/oct if I can just set the portamento to 0?


More inputs, more fun! The Chewbacca Defense (The PCO traditionally has two 1V/Oct inputs...)
dksynth
any clarifications on the way the portamento control is working? The knob seems to work properly with a constant CV input to the portamento VC jack. Otherwise the Portamento knob doesn't seem to have the expected effect.
nordlead
dksynth wrote:
any clarifications on the way the portamento control is working? The knob seems to work properly with a constant CV input to the portamento VC jack. Otherwise the Portamento knob doesn't seem to have the expected effect.


The voltage controlled Portamento works like this: feed a 1V/Oct CV signal (e.g. from a sequencer) into the top jack (IN- not the 1V/Oct inputs) - that's essentially a (special) 1V/Oct input, the jack underneath lets you insert a CV that (in combination with the knob) controls if and how strong the portamento effect shall be - bigger jumps in CV and or the 1V/Oct signal cause stronger sliding effects. However, beware that the slew rate can be set to quite slow which can mean that when using a fast paced sequence it can give the impression that very little portamento is happening simply because the pitch or control CV changes before much has happened yet. Using a sequencer with 2 separate outputs (one for pitch and one for portamento amount) is ideal to create sliding sequences.
dksynth
I understood this part clearly, but thank you for outlining it.

trying to be clearer about my question:

I'm finding it impossible to get nice long slides without feeding the PORTA VC control a voltage in addition to turning the PORTA knob up.

When my 1V/Oct signal is going to the IN jack above the PORTA knob, there is only very slight sliding of the notes at the maximum PORTA knob position when nothing is plugged into the VC jack for PORTA. I still clearly hear my sequence unless there are jumps of 2 octaves or more, then I hear a slight slide.

When a constant CV is fed into the VC jack, then the portamento knob works as expected (turn it up or down to slide notes more or less).


2 I've built and others who have built them say the same. Sockmonkey above mentions something similar. Does this design require CV into the VC PORTA jack to slide notes?
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