VCO 1 and VCO 2 down by 4 octaves , Tunning stack in TUN

[Rebirth606]

I just got second hand MatrixBrute from E-bay ( reputable seller) and rigth from the box the two VCOs is down by 4 octaves.
Is this hardware issues or software ( the synth has last Firmware available).
I reloaded the firmware and factory patches  - the problem still the same.
Tuning not possible ,stuck in "TUN"  forewer.
I'd like to have a quick answer if possible before ship it back to seller.

[standingwave]

Hello,
 I am just now experiencing the same issue with mine. I have had no problems until now since my purchase in August.
 Did you find a solution?
 Thanks.

[standingwave]

Through troubleshooting, I believe I've found the cause for this behavior:
 When running the Auto-tuning feature, any CV being sent to the VCO1 or VCO2 pitch  in slews the internal tuning memory. Though experimentation, I have been able to get VCO2 into the correct octave range. That being said, I don't k ow exactly how I did it and I can't get VCO 1 to get to the correct centre octave yet either.
 I've opened a ticket with support but would definitely appreciate any input.

 If any of the Arturia developers are reading: Next firmware update should disable CV input when performing self tune.

 Wish me luck!

[standingwave]

I solved the issue!!!
 
 So, as I discovered, CV input will slew the internal tuning system and once it "remembers" the slewed tuning voltages it will continue to use them.
 -VCO 1 and VCO 2 send constant pitch voltage: I patched "VCO 1 pitch CV out" to VCO 1 pitch CV in" , put a macro knob as a modulation source for VCO 1 pitch and turned down the voltage by the 4 octaves at middle C. Now VCO 1 pitch (and VCO 2 pitch, they are connected) are down by 8 octaves with the modulation source.
- Run the tuning procedure as you normally would. (if you press "hold key" and open the vca prior to running tune, you can here the VCOs moving around)
You want the MXB to bring VCO 1 up to pitch with CV voltage pushing it into the negative.
- Once the MXB has tuned itself, unplug the CV self patch (it will be wildly out of tune)
-Run the tuning procedure again before power cycling the synth.
- Now VCO 1 should be in tune and at the correct octave!!
- Repeat the process for VCO 2

 *You may have to do the procedure a few times and in smaller increments.

 It took some time for me to trip into the solution, but hopefully the next person will find this post first.
 Cheers!

[Guillaume Arturia]

Hey Guys,

Sorry for the troubles faced with your Matrixbrute.

After being contacted and after investigating this further here's what we found :

- When performing an autotune with a voltage sent through the CV pitch input with HotFix firmware 1.0.1 b108 the Tuning then drops because of the CV pitch in voltage sent.

Normally in this case, simply Powering the unit OFF and then ON should immediately solve the issue and restore the OSC tuning value to its default value.

- However, if the user before swithing the unit OFF and then ON updates his unit to the latest firmware revision 1.1.0 b73 the autotune will then fails because the target tuning is wrong.

From there even powering the unit OFF and then ON doesn't solves the issue.

In this case, in order to fix this issue here a more easier workaround to follow :

- Revert back to the previous firmware revision  : 1.0.1 b108

http://downloads.arturia.net/products/matrixbrute/firmware/MatrixBrute_Firmware_Update_1_0_1_108.mbf

From there perform an autotune again (Make sure to let the unit warm up around 30 minutes and to wait for the Autotune to end : may take up to 5-10 minutes depending on the detuning and may not be indicated as still tuning on the display, so let it tune your synth during around 15 minutes to ensure that the tuning properly ended).

From there you should be able to turn it OFF and ON and then have the oscillator properly tuned and you should be then able to upgrade your unit firmware to the latest revision without any problem.

As an information, this bug was already fixed with latest FW which means that once updated you won't face this issue anymore and simply powering it OFF and then ON should then systematically restore the OSC to their default tuning value.

I hope that this will help other users potentially affected with the same issue.

Best regards,
Guillaume