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amongstmyselves
Joined: Sep 01, 2012 Posts: 20 Location: Australia
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Posted: Thu Sep 06, 2012 10:45 pm Post subject:
Affordable Oscilliscope for MFOS or NOT ? |
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Hi all,
I'm embarking on a MFOS mega synth (Ultimate, Plus, etc etc) for 2013.
Something I don't have in my arsenal is an oscilliscope. Ray says you need one for the VCOs and turning the VCF so what are people using ?
I've come across this small Arduino based unit - http://www.seeedstudio.com/depot/digital-storage-oscilloscope-with-panels-p-514.html?cPath=174
Would this do the job do you think ?
Steve R. |
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bubzy
Joined: Oct 27, 2010 Posts: 594 Location: United Kingdom
Audio files: 64
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Posted: Fri Sep 07, 2012 4:26 am Post subject:
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hey thats a nice looking scope, and a good price!
some guys here use this http://code.google.com/p/dsonano/
its a bit more pricey
.... oh
after a bit of googling, looks like its from the same guys _________________ _Richard_ |
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ashleym
Joined: Aug 20, 2009 Posts: 181 Location: uk
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Posted: Fri Sep 07, 2012 5:32 am Post subject:
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Steve,
The scope will help looking at wave shapes but a multimeter with frequency counter will give you a more accurate reading than counting squares on a scope for giving you the frequency of a wave.
Have a look at these, they are based in Oz
http://www.bitscope.com/
you get a lot more than the Arduino based units. A LOT more. I have been eyeing one up to go with a Raspberry Pi. _________________ http://soundcloud.com/for-mash-get-ash |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Fri Sep 07, 2012 5:39 am Post subject:
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I use the DSO quad which is the nano's big brother (as in has more capability, it's about the same form factor).
I've come to find that the frequency measurement and even the Vpp measurement are often wrong, and highly dependent on the relationship between the actual frequency and the time scale selected. Particularly for channels other than the first one. However, if you know the time and voltage scales, the waves *are* always drawn to correct scale and you can directly view/calculate these values. The other commonly known issue with it is that the input capacitance interferes at very very high frequencies, but for audio work that hasn't seemed to be any issue.
I considered this one when I ended up buying the quad and I seem to recall some negative reviews...of course for $50 it's a great bargain I'm sure.
Honestly, if you have the space for it, used scopes are available on eBay and Craigslist at very reasonable prices, on the order of $50 to $100, and you'll probably get a higher quality scope. The main reason I got the quad is that I *don't* have the space to conveniently store a big old boat-anchor scope.
Edit: I did really want a bitscope, but it was half again more than the quad and I simply wasn't able to swing it at the time. Maybe eventually....
Edit 2: I should pay attention to where people are from...I have no idea if eBay or Craigslist or similar services are available in Oz... |
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amongstmyselves
Joined: Sep 01, 2012 Posts: 20 Location: Australia
Audio files: 1
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Posted: Sun Sep 09, 2012 10:25 pm Post subject:
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Thanks for all the advice(es).
elmegil I think has the best advise and that's to keep an eye out on Ebay (which we do have in Oz). Just having a quick look now I've come across a
BWD OSCILLOSCOPE - CRO - Model 530A DUAL TRACE for $65. It's a cathode ray type but luckily I have the space for this sort of thing.
And ashley I do remember now that Ray W. says you need a frequency counter.
Can you get something that does both ?
Steve R. |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Mon Sep 10, 2012 4:44 am Post subject:
Re: Affordable Oscilliscope for MFOS or NOT ? |
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Hi Steve - I've got one of those I was going to build into a small synth - it works pretty well - and does have a freq. counter built in.
I use a full size scope for my building - if you search for a bit on E-bay you can prolly find a decent used analog scope for $100-$150 that will serve your DIY for years and years.. _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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amongstmyselves
Joined: Sep 01, 2012 Posts: 20 Location: Australia
Audio files: 1
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Posted: Mon Sep 10, 2012 3:09 pm Post subject:
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Thanks RF
Interesting to see you have the small scope in your synth. That would be fun.
I've come across another smaller computer based scope which is the DSO Nano V2 - http://www.seeedstudio.com/depot/dso-nano-v2-p-681.html?cPath=174
This looks much better - especially the scan time whic is 1ms.
For size and portability this certain is a player.
All things considered I really only need the scope for the Gigantor (current name for my synth), though Interositer v2 (This Island Earth) also suits.
Let's hope I make the right selection.
Steve R. |
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kvitekp
Joined: Feb 24, 2012 Posts: 22 Location: Santa Clara, CA
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Posted: Tue Sep 11, 2012 10:39 am Post subject:
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Steve,
Those cheapo digital scopes will not replace an analog scope for Synth DIY, the refresh rate is simply not fast enough and precision is way off for signals you'll have to look at.
Even the full fledged DSO like Rigol DS1052E I have is not as good for tasks like Ray's VCO tuning procedure as my good old Tektronix 2225 is.
I'd highly recommend getting a decent pre DSO era 20Mhz Tektronix or HP scope from craigslist or ebay for US$100~200, they are very reliable, hold calibration over years, and have great resale value, so chances are that you'll be able to sell it for the same price when you're done.
/Peter |
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ashleym
Joined: Aug 20, 2009 Posts: 181 Location: uk
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Posted: Tue Sep 11, 2012 11:22 am Post subject:
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Steve,
Dont forget places like this
http://www.controlelectronics.com.au/used/products.html
Sometimes companies like this will lease equipment, at least they do in the UK. So you can get the much recommended Tek for the short time you need one. But it is worth getting the right tool for the job, be that a soldering iron, wire strippers, cable or scope. If you get a good scope you can use it for a long time as they are designed for heavy use in a lab rather than hobby use. _________________ http://soundcloud.com/for-mash-get-ash |
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amongstmyselves
Joined: Sep 01, 2012 Posts: 20 Location: Australia
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Posted: Tue Sep 11, 2012 4:02 pm Post subject:
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Thanks again guys for putting me straight on the "cheaper" options.
I'll take every ones suggestions and I'll wait until closer to the time comes for construction to start as I'm still working on my Timelapse Motion Control Project at this moment, hopefully that will be finished this year.
All the best and I'll keep everyone posted,
Steve R. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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