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Author Topic: Minibrute 2S-Global tuning a bit wrong  (Read 8373 times)

Duke84

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Minibrute 2S-Global tuning a bit wrong
« on: May 24, 2018, 03:06:33 pm »
Hi guys, I've just purchased a brand new minibrute 2S (wich is amazing).
My issue is with the tuning...
The global tune, keeping the pot at 12 o' clock, is totally flat, almost a whole semitone under the selected note.
Of course, I can tune the synth by turning clockwise the global tune knob, but is really far away from h12. Let's say between 14 and 15, and none of the video I've seen on the tube seems to have the global tune knob such twisted as mine to achieve the correct note.
The synth was left on to warm up before the use, obviously :)

domiag

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #1 on: May 24, 2018, 03:52:38 pm »
Mine's the same. Seems like a weird thing to not align perfect pitch to 12 o'clock. It's more like 14-15 as you say.

theluggage

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #2 on: May 24, 2018, 07:29:36 pm »
Me three - correct tuning on mine is at about 2 o'clock (and yes, this is after "warming up")  Interesting that it's so consistent.

I guess this could be corrected using the trimming screws around the back (if there were any instructions) but I'm not sure its worth the risk of making things worse just to have the master tune at 12:00.

SpiderLab

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #3 on: May 24, 2018, 11:11:35 pm »
Yep mine is between 2 and 3 o'clock  :-[

Terrym

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #4 on: May 24, 2018, 11:28:43 pm »
Hi All there is a tune screw on the rear but you need a tuner to get it correct i had to do this in testing on both my units
so if your looking at the rear there are 2 sets of screw holes  next to each vco
one on the right is offset and the left one is scale .
if your out by a few semitones try adjusting the right one only.
don't play with the other (left) of each vco
Now you do this at your own risk
Don't say i didn't warn you if you don't know what your doing
Also remember to let your unit warm up for a while this is an analogue machine.

I take no responsibility for messing your tuning up.

Good luck
TerryM
ARTURIA Tester for Minifreak,All software Polybrute,Keystep pro,Audiofuse range, Microfreak,Kl49mkII,DrumBrute,Spark,Analog lab3,KLE,kl88,matrix12,Semv,Beatstep,Minibrute 2,Pigments
ASC,Vcol6, Beatstep pro, VCOL8, Synclavier v.Minibrute2s

theluggage

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #5 on: May 25, 2018, 12:08:58 pm »
Thanks @terrym - I guess using a plastic trim tool rather than a metal screwdriver would be de rigeur too?

I think I'll leave well alone unless/until I want to transpose the whole unit up for some reason (I think one of the examples in the book does this) and run out of range on the master tune knob.

O-li Arturia

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #6 on: May 25, 2018, 01:11:31 pm »
As Terry said, you can adjust the offset using the trimmer at your right when you're facing the rear pannel.

FYI, the purpose of the left one  is to adjust the scale/slope of the VCO pitch.

If you really want to re-adjust your scale it is a bit more tricky. One option is to play a 4 steps sequence C1-C2-C3-C4, check the result on a tuner, and turn both trimmers accordingly.


YESMAN

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #7 on: May 26, 2018, 01:59:02 pm »
   Mine tunes-up at 12 o'clk. What I found was that OSC 1 was very unstable pitch wise, it would be fine, then jump around (no modulation happening). When I went to try to adjust the Osc with the rear panel trims the problem became worse. As I touched the scale trim (plastic screwdriver) the pitch would jump and sometimes disappear. I opened the unit and re-flowed the solder on the trims. Problem gone, tuning very stable. A good day.
     B-

Edouard_Arturia

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #8 on: June 12, 2018, 01:38:56 pm »
Hey Guys.

First, please make sure the OSC1 & OSC2 Tune and Fine tune knobs, plus the Global tune knob are being properly set at 12 o'clock.

Once it's done, if the pitch is not tracking regularly over the octaves, you will need to recalibrate the oscillators.
The trimmers on the back of the unit allow to adjust the oscillators slope and offset to make sure that a note played in tune in the lower octave will also be in tune in the higher octave.

To recalibrate your oscillators, here is how to proceed:

1. Turn the unit ON, and let it warm up for 30 to 45 minutes

2. Set the oscillators controls as below:
​​
​​



3. Start by the Oscillator one.
Connect the audio output to a tuner. Increase the Oscillator 1 Square level in the mixer.
Open the VCF.
Open the VCA with the Att 2 > Amp potentiometer.

4. Play a C3 and turn the VR1 / VR3 trimmers to adjust the oscillators offset until you obtain a C3 (261.6Hz) on the tuner. (Note: C3 = Pad 1 with no transpose)

5. Then play a C2 / C3 / C4 and C5, and turn the VR2 / VR4 trimmers to adjust the slope.
The aim here is to have each C as close as possible from their perfect tuning, which are in Hertz:

C1 (65.4 Hz)
C2 (130.8 Hz)
C3 (261.6 Hz)
C4 (523,25 Hz)
C5 (1046,50 Hz)

6. Repeat steps 4 and 5 until the results converge into the best possible pitch tracking over all octaves.
Note: As these are analog oscillators, you will always have a difference of a few cents between the lower and higher octave, but it is part of what makes the analog sound "alive"  ::)

7. Now continue with the Oscillator two to do that:
Lower the Oscillator 1 square level
And turn up the Oscillator 2 level
And repeat the steps 4, 5 and 6 until you get the best result as possible.

Cheers
DGDGDGDGDG

shmuelyosef

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #9 on: June 13, 2019, 09:24:41 pm »
Just for the record, on my 2S the Global tune rests ~3:00 after fully warming up...I decided that as long as everything else works, this is OK but it violates my personal aesthetic

shmuelyosef

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #10 on: June 13, 2019, 09:33:00 pm »

My MB2S tunes up at 4 o'clock...a little worrisome, however...

from the description below, this seems fraught with danger to me. From the description (as an electrical engineer) I'm puzzled by using TWO potentiometers (VR1-VR2) to adjust ONE variable (C3 offset)


Similarly for VR2-VR4 adjusting slope...does VR2 adjust the C1 and VR4 adjusts C5 to increase/decrease the slope from bottom/top?


jeff





 
Hey Guys.

First, please make sure the OSC1 & OSC2 Tune and Fine tune knobs, plus the Global tune knob are being properly set at 12 o'clock.

Once it's done, if the pitch is not tracking regularly over the octaves, you will need to recalibrate the oscillators.
The trimmers on the back of the unit allow to adjust the oscillators slope and offset to make sure that a note played in tune in the lower octave will also be in tune in the higher octave.

To recalibrate your oscillators, here is how to proceed:

1. Turn the unit ON, and let it warm up for 30 to 45 minutes

2. Set the oscillators controls as below:
​​
​​



3. Start by the Oscillator one.
Connect the audio output to a tuner. Increase the Oscillator 1 Square level in the mixer.
Open the VCF.
Open the VCA with the Att 2 > Amp potentiometer.

4. Play a C3 and turn the VR1 / VR3 trimmers to adjust the oscillators offset until you obtain a C3 (261.6Hz) on the tuner. (Note: C3 = Pad 1 with no transpose)

5. Then play a C2 / C3 / C4 and C5, and turn the VR2 / VR4 trimmers to adjust the slope.
The aim here is to have each C as close as possible from their perfect tuning, which are in Hertz:

C1 (65.4 Hz)
C2 (130.8 Hz)
C3 (261.6 Hz)
C4 (523,25 Hz)
C5 (1046,50 Hz)

6. Repeat steps 4 and 5 until the results converge into the best possible pitch tracking over all octaves.
Note: As these are analog oscillators, you will always have a difference of a few cents between the lower and higher octave, but it is part of what makes the analog sound "alive"  ::)

7. Now continue with the Oscillator two to do that:
Lower the Oscillator 1 square level
And turn up the Oscillator 2 level
And repeat the steps 4, 5 and 6 until you get the best result as possible.

Cheers
« Last Edit: July 25, 2019, 02:44:44 am by shmuelyosef »

erlsfield78

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Re: Minibrute 2S-Global tuning a bit wrong
« Reply #11 on: June 05, 2020, 08:56:10 pm »
mine is set at 11 o clock - tuner shows perfect pitch there.
Regarding power, do i need to leave this on all the time or can i turn it off?

 

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