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Unwanted noise on almost every power on

Unwanted noise on almost every power on
« on: April 22, 2016, 12:46:52 PM »
Hi,
I have a brand new (of course) OB-6 in my room.
After some days of use I noticed that almost any time I switch it on I hear the patch with an unwanted noise sound. The noise doesn't disappear when I change patches. Only when I switch the OB-6 off and on the noise sound disappears.
On every power on and off there is also a really loud click noise coming out of the speakers and headphones.
Is that a hardware problem or could this be fixed with an firmware update?
Thanks,
Florian

Re: Unwanted noise on almost every power on
« Reply #1 on: April 24, 2016, 10:48:41 PM »
pretty sure you should turn off the amp/speakers or mute the channel the synth is in when powering it down. i think the noise you hear is normal. the tempest does this and i think its normal due to how the hardware is designed.

as for power up, i usually turn speakers/amp/mixer on last so i cant comment on the startup noise.

Re: Unwanted noise on almost every power on
« Reply #2 on: May 28, 2016, 07:23:38 PM »

Hello,

Mine did that from day 0.
I don't think its a major problem,
but the noise gives me earache, so I
just turn on the speakers after synth
has been on and warmed up.

Don't really have this problem with other synths,
but not a major issue   8)

Horace

Novem

Re: Unwanted noise on almost every power on
« Reply #3 on: June 12, 2016, 05:41:51 PM »
My Prophet 6 was doing the same thing, turn the AMP sustain all the way down..no more pop!


N.

Re: Unwanted noise on almost every power on
« Reply #4 on: June 14, 2016, 08:30:12 AM »
I have not noticed any unusual noise base.
DSI Equipment: Poly Evolver Keyboard, Evolver desktop, Prophet 8,  Pro-2, OB6, P-12
 

https://Soundcloud.com/wavescape-1

Re: Unwanted noise on almost every power on
« Reply #5 on: June 14, 2016, 12:36:16 PM »
When starting always, aways turn your monitor on last.

When finishing always, always turn your monitor off first.


Re: Unwanted noise on almost every power on
« Reply #6 on: June 16, 2016, 11:03:52 PM »
All my DSI gear does it and it can be pretty frustrating. My monitors are on all the time as their switches are round the back. I'm not sure why they didn't include some of start up muting circuitry.

Re: Unwanted noise on almost every power on
« Reply #7 on: July 06, 2016, 03:12:25 AM »
Well, a lot of analogue gear do that, and this have been true for the last 30 years or more; my mackie mixer do that, for example.
This is why the usually good practice is always: switch on your speaker last, switch off your speaker first.

Maurizio

PS: just arrived on the forum, waiting for my OB-6;

Re: Unwanted noise on almost every power on
« Reply #8 on: July 06, 2016, 10:12:48 PM »
Well, a lot of analogue gear do that, and this have been true for the last 30 years or more; my mackie mixer do that, for example.
This is why the usually good practice is always: switch on your speaker last, switch off your speaker first.

Maurizio

PS: just arrived on the forum, waiting for my OB-6;

The OB-6 doesn't just 'pop' on power-on.  It sounds like snap, crackle, pop for 2-3 seconds, like something is broken.


Re: Unwanted noise on almost every power on
« Reply #9 on: July 07, 2016, 01:10:09 AM »
The OB-6 doesn't just 'pop' on power-on.  It sounds like snap, crackle, pop for 2-3 seconds, like something is broken.

I remember having some equipment (may be it was my Matrix 1000 ?) that at switch off made an oscillator sweep up
two/three octaves :->.

Yes, on the other side, some other equipment have a muting system too.

Maurizio

Re: Unwanted noise on almost every power on
« Reply #10 on: December 27, 2017, 12:51:28 PM »
no pop on power on for me but when I use my phones I can hear a loud pop when powering off (even with volume and AMP sustain turned down) is this normal ?
« Last Edit: December 27, 2017, 01:00:04 PM by StephDamo »

Re: Unwanted noise on almost every power on
« Reply #11 on: December 27, 2017, 02:02:31 PM »
Pretty much all my synths will produce some kind of noise when powering them on, or off. There are a few exceptions (like my Korg DW8000 which has a muting circuit inside that cuts the output whilst booting up), but a good rule of thumb is to always power all your synths first, and then your amp (or monitoring system) last.
Even my brand new DeepMind 12 produces a large thump when finishing booting up, and it even has a relay to prevent this !
The worst one I have is the Ensoniq SQ80 which will produce a sort of whining (like it's dying) when powering it off ! lol !
My OB6 produces a static click when powered on, and a faint one when powering off.
« Last Edit: December 27, 2017, 02:04:20 PM by AlainHubert »
Minimoog D (vintage), DSI OB6 (Desktop), Oberheim Matrix-6 (MIDI Controller), DSI REV2-16, Mac Mini Unibody 2010 (audacity).

Re: Unwanted noise on almost every power on
« Reply #12 on: December 29, 2017, 08:29:28 AM »
Modal synths are the worst for this. the 008 makes an horrific sound if powered up with the volume up. I'm thinking of getting one of those passive volume control knobs you can put between your monitors and mixer, then you can easily mute the speakers before switching gear on.


Re: Unwanted noise on almost every power on
« Reply #13 on: December 29, 2017, 08:53:28 AM »
Leaky input decoupling capacitors on the mixer channel may cause this; you can measure from hot to ground (synthesizer unplugged, turn the fader all the way down) to see if you've got a few mV DC. I've seen this happen with quite a few AC-coupled designs.

That said - yeah, don't switch on your synths with the mixer channel unmuted - this is Audio 101-level stuff.  ;D
Sequential / DSI / Pioneer stuff: OB-6 Desktop, Prophet 12 Desktop, Mono Evolver Keyboard, Pro 2, TORAIZ AS-1, Prophet-600 Gligli, Prophet 2000