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Hardware Instruments => MicroBrute => MicroBrute - General discussion => Topic started by: shawbro on December 11, 2013, 02:49:16 pm

Title: Audible VCO signal Without Touching any Keys
Post by: shawbro on December 11, 2013, 02:49:16 pm
I just picked up the microbrute yesterday and I noticed there is a low level vco signal coming from the unit constantly when I am not hitting any notes. Any of you guys having this issue? This sucks when you are trying to record something.


Title: Re: Audible VCO signal Without Touching any Keys
Post by: Bruno@arturia on December 12, 2013, 10:39:44 am
can you answer the following questions:
1/ can you ear it if all the mixer waveforms are at 0 in the mixer. (filter LP, cutoff max, resonance 0)?
2/ can you ear it if : square volume=max, filter LP, cutoff min, res=0

Title: Re: Audible VCO signal Without Touching any Keys
Post by: shawbro on December 12, 2013, 01:59:59 pm
Thanks for the response. I will check and get back to you.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Bruno@arturia on December 12, 2013, 02:08:16 pm
one more:  is it related the master volume knob position, I mean in a different way than more volume means more VCO sound?
Title: Re: Audible VCO signal Without Touching any Keys
Post by: shawbro on December 12, 2013, 04:04:55 pm
Ok. ill add that to the check list. Thanks!
Title: Re: Audible VCO signal Without Touching any Keys
Post by: lordschleife on December 12, 2013, 09:18:10 pm
I am getting a high pitch VCO sound in the background of the headphone out, but the line out seems fine
Title: Re: Audible VCO signal Without Touching any Keys
Post by: BOB1 on December 13, 2013, 08:15:59 pm
bruno, 1 and 2 have no effect on the vco noise, it gets louder until 1 o'clock on the master volume and decreases from there on.

It's more noticable on the headphone out with low impedance earphones/in ears. Can replicate it on the line out with more gain in the external mixer. Can play melodies with it, it's the raw ungated vco sound
Title: Re: Audible VCO signal Without Touching any Keys
Post by: cskerik on December 15, 2013, 03:15:12 am
I'm not in front of mine now, but I think I had the same issue and it was related to the brutalizer self oscillating... 
Title: Re: Audible VCO signal Without Touching any Keys
Post by: MicroBren on December 15, 2013, 10:43:12 am
I'm having the exact same issue as BOB1.
A constant low amplitude buzz at 1 o'clock to 3 o'clock on the Master Volume.

I believe it's a VCO bleed through.
Here is why: pitch bend changes the pitch of the noise, triggering a key in a different octave range will hold the note and the step sequencer seems to come through the noise.

These are my settings:
- No VCO turned up, no waveform modifier up.
- Filter cutoff max
- Zero resonance
- Zero LFO
- Zero Envelope

Also tried Bruno's questions. 1 and 2 have no effect on the noise.

I've included a recording of the problem showing the pitch bend, then step sequencer, then octave ranges.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: BOB1 on December 15, 2013, 01:31:13 pm
it is vco bleed through, same as when I do not turn down the fixed cv knob on my modular vca
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Bruno@arturia on December 16, 2013, 09:39:47 am
As the filter does not looks to modify it, it's seems to be the audio output that picks up a bit of VCO signal when going through the ribbon cable between VCA and Output jacks. It does explains why the sound changes according to the output load impedance (both volume pot and HP impedance).

Title: Re: Audible VCO signal Without Touching any Keys
Post by: Activ-8 on December 17, 2013, 03:01:25 pm
As the filter does not looks to modify it, it's seems to be the audio output that picks up a bit of VCO signal when going through the ribbon cable between VCA and Output jacks. It does explains why the sound changes according to the output load impedance (both volume pot and HP impedance).

so should this be happening???, its more noticeable when using the headphones plugged into the micro.., for me the phasing sound disappears when i have the master volume before 10oclock and after 2oclock to max volume.. i do find this a bit strange..
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Yanneck on December 17, 2013, 03:58:18 pm
Same problem here between ten o'clock and master volume max. After 2 o'clock it's very, very soft, but noticeable. Checked it with diffrent cables and earphones, headphone and line out.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Mmarsh on December 17, 2013, 08:37:00 pm
While I agree that bleed-thru is bad, there is a solution if you are recording: use a gate.  Most DAWs have such a thing I think.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Yanneck on December 17, 2013, 09:23:21 pm
Not everyone uses a DAW. Or not always, especially on the run.  :P

Tried it now with direct input from Microbrute to my laptop. If I turn up the MicIn of my Laptop to max the range of signals (from the Microbrute) goes from Master Volume Min to Master Volume Max. After 2 o'clock it is again only noticeable very soft. Maybe I will try to get my cash back because of that.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Mmarsh on December 18, 2013, 06:26:07 pm
This: http://www.sweetwater.com/images/items/1800/NS2-xlarge.jpg  :P
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Yanneck on December 18, 2013, 07:19:55 pm
Now I was in store and they gave me a new one. I tried it in store and everything seems fine. But now, at home, I can play tones with Resonance Max and amount and rate of lfo. It seems likebthe Microbrute hangs up or so. this is so bad . . .   :-\
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Yanneck on December 18, 2013, 09:43:50 pm
Hm, after playing around for one hour or so everything seems fine, sorry for the last post. Doesn't work. See this post: http://www.arturia.com/evolution/smf/index.php?topic=14605.0
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Bruno@arturia on December 19, 2013, 10:14:55 am
I think we are talking about three different things here.

First one, as I said it looks like a cross talk between VCO output, and VCA output. Microbrute do has a bit of it for sure (as many analogs), but it should be an issue. If it's too loud, maybe a ribbon cable inside is not in a proper position. We can check this if you want.

The second one:
Quote
I can play tones with Resonance Max and amount and rate of lfo

I'm not sure I really understood this, but a VCA has an attenuation, often around -70dB, it does not perfectly close when gate is Off. So if the filter is self oscillating very hard, the signal is very hot it's not surprising you can hear it a bit at the output.

Third one:
Quote
See this post: http://www.arturia.com/evolution/smf/index.php?topic=14605.0
As I replied to the post, HP filter does not close totally when cutoff is maxed. Only LP closes.
It's by design. Same on minibrute.

Finally, it's not an excuse for everything of course, but keep in mind the price you paid, compared to the available features. With this ratio, it very difficult to match quietness of a very high end synth.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Bacon on December 19, 2013, 12:35:36 pm
I can play tones with Resonance Max and amount and rate of lfo. It seems likebthe Microbrute hangs up or so. this is so bad . . .   :-\
Do you mean that you get a tone out of it with the oscillator levels at minimum, the filter resonance at max, and the VCA env set to Gate (or set to Env but with the sustain at max)? If so, this is not a fault, but a very desirable feature the filter is supposed to be able to self-oscillate. If the filter on mine didn't go into self-oscillation I'd return it to the store.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Yanneck on December 19, 2013, 09:05:46 pm
I mean, Highpass, Cutoff 50 %, Resonance 100 %, LFO Rate 100 %, LFO Amount 100 %. If I then press a key it plays and plays and plays and won't stop till I turn down Resonance a little bit. If I then turn it up again it plays and plays and play. I then can play with LFO and the signals are changing. To me this seems a bit buggy, but I don't know much about analog synths. Microbrute is my first one.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Mmarsh on December 20, 2013, 01:25:02 am
I missed that this is high pass mode. No 2-pole high pass filter will perfectly close, it's an artifact of the design.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Bacon on December 20, 2013, 07:39:21 am
I mean, Highpass, Cutoff 50 %, Resonance 100 %, LFO Rate 100 %, LFO Amount 100 %. If I then press a key it plays and plays and plays and won't stop till I turn down Resonance a little bit. If I then turn it up again it plays and plays and play. I then can play with LFO and the signals are changing. To me this seems a bit buggy, but I don't know much about analog synths. Microbrute is my first one.
Analog synths do unexpected things sometimes, especially when you push some settings to the limits. Back in the 70s and 80s some manufacturers saw this kind of behavior as flawed and limited how far you could push the sound. Look at the Roland Juno 106 for example. From what I remember it can sound very nice and musical, but it's hard or impossible to make it sound nasty or brutal.
I haven't tried the settings you describe, but I will. It's probably just one of the cool, unexpected things you discover when you play around with a synth like this. To me this seems like a feature, not a bug  :)
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Yanneck on December 20, 2013, 12:10:25 pm
Here is a video of it in action: http://www.youtube.com/watch?v=Vrxi-r6tURQ

 :)
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Fortunato on December 20, 2013, 07:02:28 pm
Hi people. i have this exact vco bleedon problem. more auible when volume is at 1 o clock and can be played from the keys.
Bruno, if you say its the ribbon cabe position could you please give some indications to fix it?
my unit has traveled a lot and it'll be a shame to have to ship it back. besides tearing electronic things down its always fun =P
i guess its because an electromagnetic field is inducing the noise to the amp?
thanks in advance.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: kas_lar on January 04, 2014, 10:37:45 am
Is there really no solution other than-> use a gate? This would no be possible to do live for me.

Has anyone tried to return their Microbrute and get another one?
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Yanneck on January 05, 2014, 08:14:01 pm
Quote
Has anyone tried to return their Microbrute and get another one?

Hi, yes, I went to store and they gave me a new one after testing my old one. The new one runs without signals all the time.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: D4T4 on January 06, 2014, 10:56:00 pm
Hey guys, I have just got a Microbrute today and was going to ask this question, but it seems the original poster beat me to it, although I maybe have a bit of a better idea where my noise is sourced.


With all oscillators fully off I have a background noise which appears to be caused by the phase shifting (osc?) of the "Ultrasaw".

This noise tracks the pitch of each key, and is maximum with the "Master Volume" at 65-70% after which it tails off. It can be further increased by turning up the "Ultrasaw" nob to its max (still with all osc fully at 0). At this point it is about equivalent in volume to turning the saw wave up to its second mark.

Anyone up for a quick test of their own Microbrute for me to confirm if this is normal, or whether I should think about shipping mine back off to the supplier for a replacement. I'd add this is evident through both line and headphones. Worst case it is liveable with as turning the master volume to its max reduces the noise, and its hardly noticeable when you are making loony noises on the thing, but not ideal from a new piece of kit I've forked out my hard earned cash on.

Cheers.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: D4T4 on January 07, 2014, 12:42:48 am
Scrap that last post, mine just totally died!

Left it sitting switched off but plugged into the power supply, and went back to it about an hour later, now when you switch it on the lights flicker on and back off and it just sits there making a constant tone, no lights and none of the controls respond at all.

Gutted  :'(

Oh well, back to the shop it goes.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: kas_lar on January 07, 2014, 10:54:49 pm
Hi guys.
I returned mine and got a new one without the VCO noise  :) It's a lovely machine!
Title: Re: Audible VCO signal Without Touching any Keys
Post by: alan bg on January 09, 2014, 01:50:54 pm
I too have this problem. Very frustrating indeed. Also, having just now updated the firmware i find the sequencer no longer plays ! I have tried resetting to defaults and recording new sequences but to no avail. Silence is all :(
Any ideas?
Title: Re: Audible VCO signal Without Touching any Keys
Post by: alan bg on January 09, 2014, 02:04:47 pm
Ah...ooops. Scrap the sequencer comment....somehow changed to Step on....Gate in the software without intending to . sorry , honest.

Audible vco comment still holds tho
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Activ-8 on January 10, 2014, 11:08:04 am
Hi guys.
I returned mine and got a new one without the VCO noise  :) It's a lovely machine!

dude i need you to please study your new microbrute and make sure you have absolutely no vco noise/bleed because if this fact is true with your new microbrute then i'm getting mine replaced!.. for some to have this bleed and others not to is unacceptable!.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: derpityderp on January 12, 2014, 01:01:32 am
I have a similar problem to the many described here.  My microbrute plays the tone of the last key I pressed (continuously, even after the key is released, until a different key is pressed) when all the oscillators, filter, resonance, etc. are set to zero.  It's worse in the headphones and when the volume knob is set between 1 and 3 o'clock.  It's not hum or noise.  It's a tone, and its pitch can be modulated by the LFO, although changing the position of other controls besides the volume and LFO does not affect it.  I didn't expect to get a perfectly quiet machine for $300.  My Monotrons, for example, hiss and hum a bit.  But this is different and quite distracting.  I like the Microbrute a lot otherwise, but I'm disappointed with this defect, which seems to be quite common from what I've read on this forum.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: darkflow on January 12, 2014, 04:04:04 am
Ah...ooops. Scrap the sequencer comment....somehow changed to Step on....Gate in the software without intending to . sorry , honest.

Audible vco comment still holds tho
This happened to me too :P updated the firmware and I thought it killed the seq. Took me a while to figure out that the firmware update changed the setting on me haha. This should be changed in a future version.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: dhdaniel on January 13, 2014, 10:39:08 pm
I have a similar problem to the many described here.  My microbrute plays the tone of the last key I pressed (continuously, even after the key is released, until a different key is pressed) when all the oscillators, filter, resonance, etc. are set to zero.  It's worse in the headphones and when the volume knob is set between 1 and 3 o'clock.  It's not hum or noise.  It's a tone, and its pitch can be modulated by the LFO, although changing the position of other controls besides the volume and LFO does not affect it.  I didn't expect to get a perfectly quiet machine for $300.  My Monotrons, for example, hiss and hum a bit.  But this is different and quite distracting.  I like the Microbrute a lot otherwise, but I'm disappointed with this defect, which seems to be quite common from what I've read on this forum.

same here. sent a message to tech support. they said: "CAn you make sure that the switch on the back of the unit is set to KBD?"

I don't see a switch labelled as such on the back of the unit. They also mentioned that it could be caused by a grounding issue, and asked me to explain the setup, which is just headphones. Someone suggested it might be "dirty power", so I hooked it up through a power conditioner. That did not solve the problem.

They haven't replied to me since I sent a message on the 3rd, so I thought I'd try here. If I find the issue to be too detrimental, do I send it to Arturia or to the music shop from which I purchased the unit for a refund?
Title: Re: Audible VCO signal Without Touching any Keys
Post by: achtungmark on January 18, 2014, 10:21:31 pm
I have exactly the same problem, a little annoying I must say. Am running mine from headphones out to the analogue in on my Xone DB4. Can't say that I've noticed much change while changing the master volume control either.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: kikendo on January 20, 2014, 12:05:51 am
I hear this too, I can hear like background noise, from Master volume positioned at 9 o clock all the way to almost the end, with the loudest being at about past 1 o'clock, summed to a faint VCO bleed (I can pitch it with the pitchbend wheel).

When volume is at max, it goes away.
The VCO bleed doesn't bother me, but the background noise does!
Title: Re: Audible VCO signal Without Touching any Keys
Post by: shawbro on January 20, 2014, 01:23:39 pm
I have found that by turning the master knob all the up to full the vco bleeding disappears. It's very present between 2-8 say. I'm also using the line out. I don't notice it much in the headphones output.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: astraltraveler06 on February 17, 2014, 02:27:03 am
I am glad to see this is a common problem. Mine also has it.
I have owned many analog synths and, although you can expect a bit of a noisy signal, this "ghost VCO' phenomenon is unacceptable for any synth, no matter the price point. It makes it virtually unusable, particularly in a live, amplified setting. I get the feeling the problem is in the Master Volume potentiometer itself. If it was a crosstalk problem, it would be present throughout the volume range but, as other have noted, it only occurs between 10 and 2 o'clock.
Arturia needs to find a solution to this problem and soon, otherwise they'll be facing massive amounts of returns on this otherwise wonderful little synth.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: pabloevaristo on February 18, 2014, 11:41:16 am
No problem here.
But I also think the price is not an excuse for that kind of issues. It's a manufacturing problem, I think, because some of us have it and othes don't.
Sad about that (glad about me! ;) )
Title: Re: Audible VCO signal Without Touching any Keys
Post by: kassu on February 26, 2014, 01:45:23 pm
Just to add my findings: I found the same VCO bleed problem with a unit when trying it out in the store. I then asked for a second unit, which had no problems (and which I then bought, no VCO bleed in any headphone/mixer configuration so far).

The problem in the store unit sounded very clearly like some electromagnetic coupling between the VCO and the output circuitry. It was not affected by any filter/mod settings, and also not by any VCO settings, so I assume there is a fundamental square or pulse VCO internally that is always on and from which the other wave shapes are derived. Square wave/pulse signals easily couple to anything else, because they contain so many high frequency components.

It would be best if someone with this issue is willing to experiment a bit with his/her microbrute. Since Bruno here suggests these signals are going through ribbon cables, it is quite likely that the problem can be solved by just opening up your MB and moving the ribbon cables around a bit. Maybe just opening and closing the box again is enough, with a bit of luck.
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Bruno@arturia on March 03, 2014, 09:43:40 am
Quote
The problem in the store unit sounded very clearly like some electromagnetic coupling between the VCO and the output circuitry. It was not affected by any filter/mod settings, and also not by any VCO settings, so I assume there is a fundamental square or pulse VCO internally that is always on and from which the other wave shapes are derived. Square wave/pulse signals easily couple to anything else, because they contain so many high frequency components.

It would be best if someone with this issue is willing to experiment a bit with his/her microbrute. Since Bruno here suggests these signals are going through ribbon cables, it is quite likely that the problem can be solved by just opening up your MB and moving the ribbon cables around a bit.

indeed, I thinks it's coupling between two ribbon cables, you should open the machine and move the ribbons so that they are not perfectly parallel, coupling is should be much attenuated with an angle between the wires.

Title: Re: Audible VCO signal Without Touching any Keys
Post by: JayBee808 on March 04, 2014, 08:42:45 pm
I've been watching this thread unfold, mine HAD the same issue but was past the return period...

I was feeling ambitious after rebuilding a Wurlitzer last month so I tore the MicroBrute apart.  As suggested in the previous few posts, this is an issue with the ribbon cables inside.

The good news is this was an easy fix, the most time consuming bit being removing the screws.  You don't need to remove any knobs, the ribbons are accessible under the bottom panel.  There are a couple of very thin ribbon cables near the envelope controls.  The one folded back under the envelope sliders is the offender.  I plugged the unit in, played notes and moved the ribbon until it became quiet.  I did find a spot where the noise got louder, so it is highly likely that some of these are shipping with the problem way worse than others.

Bottom line, it is an easy fix and I didn't have to go a day without my Micro.  It's unfortunate that we have to deal with this at all but for a sweet synth, I won't complain.

Good luck!
-J
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Ptr on March 17, 2014, 11:40:51 am
I also have this, between the 11 and 2 settings of the master level knob it's the most audible. So, what's the recommended course of action: contact the shop, Arturia costumer service or just (have someone) open te unit and look at those ribbons. I am not technically able myself, but I could let my father have a look, if it does not require specific insight but rather general technical feeling.

However, won't I void my warranty when opening the unit?

Thanks!

Title: Re: Audible VCO signal Without Touching any Keys
Post by: cowfood on March 19, 2014, 03:35:19 am
Thank you JayBee808, The ribbon cable right under the envelope was the ticket, just pushed mine back a little, no more crosstalk, both line and hp jacks are clean now.  Took me awhile to find this thread, but the fix - 10 minutes.

-CF
Title: Re: Audible VCO signal Without Touching any Keys
Post by: Icewind on March 25, 2014, 05:22:25 pm
Just wanted to say that I also had this problem.  Took it back to the place of purchase, and got a new one.  Tried it at the shop, and everything seemed fine.  Once I got home, I noticed that I still had the bleed, but only when I turned up the ultrasaw.  I can live with that.  Although it is a little annoying.

I'm a little paranoid about opening up the microbrute to fix the issue. 
Title: Re: Audible VCO signal Without Touching any Keys
Post by: JayBee808 on March 28, 2014, 07:46:22 am
In my experience, analog synths will always require some maintenance. :-\  I've owned many over the years and opened every one at some point.

That being said... I think this fix for the Micro is extremely easy. It is really a matter of removing a BUNCH of screws on the bottom panel, gently pulling it off and then pushing the ribbon cable.  Easy to reassemble. Honestly I trust this method of repair way more than shipping the board in for the same repair. You might even end up with a used replacement, who knows how Arturia is dealing with this.

I am guessing after time and movement (mine travels a lot) this ribbon will move and become a problem again. I'm just expecting to make this adjustment on occasion.

I am also trying to figure out if there might be a way to shield that ribbon so that there isn't the crosstalk problem. Any ideas would be great!

I realize this seems like a wrong but I truly believe part of owning any keyboard is the maintenance of it. The MicroBrute is no exception. It is a wicked synthesizer and I am not concerned in the slightest.

Let me know if you have questions, glad to help out!
Title: Re: Audible VCO signal Without Touching any Keys
Post by: avinoandrea90 on May 28, 2015, 11:45:30 pm
I have the same problem but only from the main out any suggestions on how to fix it? I already used my warranty without asking them to fix that!  :-[
Title: Re: Audible VCO signal Without Touching any Keys
Post by: fellotransit on January 30, 2016, 10:32:13 pm
That being said... I think this fix for the Micro is extremely easy. It is really a matter of removing a BUNCH of screws on the bottom panel, gently pulling it off and then pushing the ribbon cable.  Easy to reassemble. Honestly I trust this method of repair way more than shipping the board in for the same repair. You might even end up with a used replacement, who knows how Arturia is dealing with this.

 :) I'm super happy that you guys figured out the ribbon cable was the problem. I opened up the back of mine last night and moved the ribbon cable that crosses over cirucuit board near the envelope section and the noise went away. I taped it with some electrical tape to the bundled cable right next to it so that it wouldn't fall close to the circuit board again. It's like brand new again.
I feel so relieved that this was an easy fix.

Thanks to JayBee808 for opening up his and letting us know!