Audible VCO signal Without Touching any Keys

[Mmarsh]

This: http://www.sweetwater.com/images/items/1800/NS2-xlarge.jpg 

[Yanneck]

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 . . .   

[Yanneck]

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

[Bruno@arturia]

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:

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:

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.

[Bacon]

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.

[Yanneck]

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.

[Mmarsh]

I missed that this is high pass mode. No 2-pole high pass filter will perfectly close, it's an artifact of the design.

[Bacon]

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 

[Yanneck]

Here is a video of it in action: http://www.youtube.com/watch?v=Vrxi-r6tURQ

 

[Fortunato]

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.

[kas_lar]

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?

[Yanneck]

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.

[D4T4]

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.

[D4T4]

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.

[kas_lar]

Hi guys.
I returned mine and got a new one without the VCO noise  It's a lovely machine!