ROLAND SYSTEM 100M OSCILLATORS

Modular Synth design and releases (Reaktor, SynthEdit, Tassman, etc.)
airbag76
KVRer
3 posts since 18 Feb, 2006

Post Tue Mar 13, 2018 8:39 am

Hi everyone

I had the idea of taking some readings of my synth oscillators and I m not satisfied especially on the lower scales. Saw, triangle and square appear in my oscilloscope totally out of shape.
the triangle very curvy instead of straight and saw - square out of recognition. As i turn the range knob to higher scales things get better yet little bit distorted.

Any suggestions? Do I have to open and tune the module from the inside?

I m posting some of my oscilloscope readings for better understanding

thanks in advance
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Distorted Horizon
KVRian
1313 posts since 17 Jan, 2017

Re: ROLAND SYSTEM 100M OSCILLATORS

Post Tue Mar 13, 2018 9:10 am

LMAO :lol:

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Distorted Horizon
KVRian
1313 posts since 17 Jan, 2017

Re: ROLAND SYSTEM 100M OSCILLATORS

Post Tue Mar 13, 2018 10:26 am

Just in case that you're serious, those are basic analog waveforms. They really look like that.

Someone can give a more scientific explanation but still, there's nothing wrong with your 100M.

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ChamomileShark
KVRian
1289 posts since 12 May, 2004 from Oxford, UK

Re: ROLAND SYSTEM 100M OSCILLATORS

Post Tue Mar 13, 2018 11:02 am

Generally analogue hardware VCO waveforms are a disgrace. The square waves in particular are appalling - they generally sag at the top. However as long as the rise and fall are straight they will sound like a pulse/ square wave.

Probably if you zoom in you will see a ragged area where the slope changes.

If they sound like the respective waveforms are supposed to sound then they are probably ok. If they've not been serviced for a while then get a competent tech to do so.

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EvilDragon
KVRAF
17083 posts since 7 Jan, 2009 from Croatia

Re: ROLAND SYSTEM 100M OSCILLATORS

Post Tue Mar 13, 2018 11:12 am

Don't forget that those waveforms are most definitely going through a DC blocker or two before the output (basically highpass filters), so this is what skewes their shapes.

Shockwave77598
KVRer
18 posts since 15 Mar, 2018

Re: ROLAND SYSTEM 100M OSCILLATORS

Post Wed Mar 21, 2018 6:32 am

Especially at the lower registers eh?

I'll bet you'll find that you have not one, but two DC blocking caps in the circuit. One is on the output of the synth. The other is the input of your sound card. Both are pretty big and usually set to block DC -20Hz signals.

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