Analogic Oscilloscope on a Sub 37

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QUbits
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Joined: Thu May 07, 2015 3:49 am

Analogic Oscilloscope on a Sub 37

Post by QUbits » Thu Jun 18, 2015 4:28 pm

Hello,

I'd like to plug my sub 37 into an analogic oscillator in order to see the waveforms i'm creating and have a better understanding on what i'm doing. I was thinking on using one like this : http://www.ebay.fr/itm/Oscilloscope-a-c ... 3cf5bc4942 but how do exactly do you plug it it ? what kind of cables do you need, i'd like to see the waveforms interractivly with filter, enveloppes and so on but also be able to hear to sound that i'm making at the same time.

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MRNUTTY
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Re: Analogic Oscilloscope on a Sub 37

Post by MRNUTTY » Thu Jun 18, 2015 8:14 pm

The simplest thing is connect the audio output of your Moog directly in to Channel X input. Set it for DC input, and input the range of 0.1V to 1V per division. You cust run a solid core (not stranded) wire wrapped around an audio cable into the BNC connection, although depending on your grounding situation adding a ground wire may improve your signal quality.

If you can ever get around to it, if there is an X/Y mode on your scope (doesn't appear to be, could be wrong), the Lissajous patterns from pairs of filter outputs (BP vs LP, etc...) can be AMAZING. Providing there are phase differences, and I don't think you can avoid this.
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

Logarhythm
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Re: Analogic Oscilloscope on a Sub 37

Post by Logarhythm » Thu Jun 18, 2015 10:20 pm

Assuming you just want to look at the audio output of the Sub37 you can start out with a PC Oscilloscope program that can receive input from your sound card. Just connect your keyboard to a line in jack on your PC and set it as the source for the oscilloscope program. I can recommend Christian Zietnitz's "Soundcard Oscilloscope" for PC, which is free to use noncommercially.

http://www.zeitnitz.eu/scope_en

I recently hooked it up with my Sub37 to better understand what the output of the oscillator looks like as it blends through the waveform shapes. :D It helped me train my ears to find the pure 50/50 square wave, and it can give lots of insight into what modulation routings are doing.

UncleToad
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Re: Analogic Oscilloscope on a Sub 37

Post by UncleToad » Fri Jun 19, 2015 3:20 am

I just bought a pocket Oscilloscope through Amazon called the DSO202 for less than £100. It is about the size of a mobile phone and uses an LCD colour screen.
I connected the probe to a jack lead plugged into the Sub 37's headphone socket and it works great !

regards

Paul

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MRNUTTY
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Re: Analogic Oscilloscope on a Sub 37

Post by MRNUTTY » Fri Jun 19, 2015 8:31 am

@uncletoad, that is SO COOOL!!! The DSO203 quad channel scope looks more useful. Really limited bandwidth buuuuuut - I am getting one NOW :-)
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

QUbits
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Re: Analogic Oscilloscope on a Sub 37

Post by QUbits » Fri Jun 19, 2015 12:35 pm

Thank you all for your different answers / suggestions !

@ MRNUTTY :

1. What do you mean by " You cust run a solid core (not stranded) wire wrapped around an audio cable into the BNC connection, although depending on your grounding situation adding a ground wire may improve your signal quality. " ? Could you please reword it in simple terms for a newbie like me ? :)

2. What is an X/Y mode, what does it do and why is it usefull ?

-

@ Logarhythm :

Could you please tell me which settings you're using for this program to look at the waveforms of your sub37 ? (If possible take some screenshots and post it here).

-

@ UncleToad

It looks interresting... Could you please post a video of your DS0202 oscilloscope (youtube or anywhere) so i could see a preview of it and also tell me which settings you are using ?

QUbits
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Re: Analogic Oscilloscope on a Sub 37

Post by QUbits » Fri Jun 19, 2015 12:40 pm

And by the way, adding a mini analogic (would be the best) or digital oscilloscope to the next moog / phatty would be a very good idea !

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MRNUTTY
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Re: Analogic Oscilloscope on a Sub 37

Post by MRNUTTY » Fri Jun 19, 2015 2:37 pm

@qubits, not sure how much plainer I can make it: take a piece of wire and wrap it around the TIP of an audio cable plugged into your synth output, and poke the other end into the CH X input of your scope. If you get excessive 60hz, then you need to add a ground connection.

WRT to X/Y mode the CH X input would provide Y-axis displacement, and the CH Y input would provide X-axis displacement. Liekly as not, your scope can only do Y-axis displacement on either channel, and X-axis displacement is determined by the time base selected with Time/Div.
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

EricK
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Re: Analogic Oscilloscope on a Sub 37

Post by EricK » Fri Jun 19, 2015 2:56 pm

I ordered a Tektronix 475 from this ebay seller and was 100% pleased with him.

http://www.ebay.com/usr/workingman.mv


Eric
Support the Bob Moog Foundation:
https://moogfoundation.org/do-something-2/donate/

I think I hear the mothership coming.

QUbits
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Re: Analogic Oscilloscope on a Sub 37

Post by QUbits » Fri Jun 19, 2015 3:08 pm

is it really usefull to use a 200mhz oscilloscope for a synth such as the sub 37 ? isnt a 10 mhz enough ? and is 2 channels necessary ?

EricK
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Re: Analogic Oscilloscope on a Sub 37

Post by EricK » Fri Jun 19, 2015 4:04 pm

You are right it is more scope than you need, but the ones that ebay seller sells have been serviced and calibrated vs a used one you might find cheaper.

I went that route rather than purchasing the O'Tool module in 5U which cost about the same.

You can find some really good deals on some vintage scopes on ebay for much cheaper if you just want to monitor waveforms. No guarantees regarding how long they will last though.

Do you want to monitor waveforms or take real measurements and work on gear?


Having two channels is nice if you ever want to compare waveforms or make interesting shapes:
https://www.youtube.com/watch?v=MGylt7fhEgM

You can probably just make a quarter inch to BNC connector cable (or buy one) to hook directly to your scope.
Support the Bob Moog Foundation:
https://moogfoundation.org/do-something-2/donate/

I think I hear the mothership coming.

QUbits
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Re: Analogic Oscilloscope on a Sub 37

Post by QUbits » Sat Jun 20, 2015 4:52 am

Hello,

I've made a quick drawing for the connexions from the sub to the oscilloscope, is it correct ? Will it work this way ?

Image

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MRNUTTY
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Re: Analogic Oscilloscope on a Sub 37

Post by MRNUTTY » Sat Jun 20, 2015 9:23 am

Hi @qubits, yup that drawing will get you there. Love the little loopies in the wires ;-)
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

QUbits
Posts: 13
Joined: Thu May 07, 2015 3:49 am

Re: Analogic Oscilloscope on a Sub 37

Post by QUbits » Sat Jun 20, 2015 2:28 pm

Totally useless loops just for fun. Haha.

I'm buying this one for 50 euros on monday, i'll post some pictures (maybe a video), hope it'll look good.

It's an old 2 x 20 Mhz analogic oscilloscope. Probably from the 70's or 80's.

Image

clif321
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Re: Analogic Oscilloscope on a Sub 37

Post by clif321 » Mon Jun 22, 2015 4:46 am

I just tried this running the Sub 37 through an oscilloscope app on my iPad (there re many available for iPad/iPhone, some free) and it works great.

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