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Oscilloscope - Total noob

Andy Betts

Taking my first steps into electronics, I've been playing around making guitar effects pedals and posting on my blog the outcomes from those adventures, it's been fun but there is one thing that keeps slapping me in the face..... The lack of advice for newby electronics hobbyists.

 

I fell into electronics as a way of making pedals for myself as I couldn't afford to buy the real thing. However, it's been made quite apparent in previous blog posts that if you're going to have fun with electronics you need the right kit. I seem to have most bases covered except the illusive Oscilloscope. To the uninitiated (me) they look technical, and the sort of thing you see in a NASA control room. However, using one is only one part of the issue...... How do you go around buying one, and what do you buy. Is it safe to buy second hand from that famous auction site, or should you buy brand new? Is there any advantage of digital over analogue? The older analogue scopes look cool and retro but are there limitations? What should the minimum specification be that I'm looking for?

 

This forum is great for electronics enthusiasts, and the amount of knowledge here is huge, but it appears the assumption could be it's for people that already know these things. that's why i'm putting this out there as a newby question. I want to buy an Oscilloscope, i'm on a budget, say a maximum of £200, i'm open to any ideas........ Discuss image

Parents

  • Hi Rachael, thanks for your reply.

     

    my intention initially is to just work on analogue guitar effects pedals, so I guess a 2 channel would suffice, however some of these analogue devices have IC's so would a 4 channel be more preferable??

     

    I'm up for using a Windows based system, as that will likely run on my laptop and it'll be portable. So that might be a better option than lugging a heavy scope around.

     

    Cheers

     

    Andy

  • in reply to Andy Betts

      wrote:

     

    my intention initially is to just work on analogue guitar effects pedals, so I guess a 2 channel would suffice, however some of these analogue devices have IC's so would a 4 channel be more preferable??

     

    I'm up for using a Windows based system, as that will likely run on my laptop and it'll be portable. So that might be a better option than lugging a heavy scope around.

     

    So it depends what IC's they are. If they are ADC's and DAC's then you'll likely be dealing with I2S/TDM for the audio and SPI/I2C for the control of these. There will likely be an MCU or a small DSP possibly too. I'd say 4-channel or 2-channel + 16 bit MSO option would be a reasonable choice but that does put the price up quite a bit. The 2-channel + 16 bit MSO version of that Picoscope puts the price up to about £380. So at this point the Digilent Analog Discovery 2 is looking like a reasonable option except that the version on CPC Farnell is the basic unit without any of the add-ons so no adapters for scope probes and no scope probes etc. You can get the Pro version from Digilent but I don't know what the cost will be shipped to the UK including any customs charges: https://store.digilentinc.com/analog-discovery-2-pro-bundle/

     

    You could start with a basic 2-channel Picoscope (or something similar) or a 2-channel regular bench scope and see how you get on. You can usually work around the lack of additional channels if you need to and you'd probably be able to resell these if you wanted to upgrade.

     

    Best Regards,

     

    Rachael

Reply
  • in reply to Andy Betts

      wrote:

     

    my intention initially is to just work on analogue guitar effects pedals, so I guess a 2 channel would suffice, however some of these analogue devices have IC's so would a 4 channel be more preferable??

     

    I'm up for using a Windows based system, as that will likely run on my laptop and it'll be portable. So that might be a better option than lugging a heavy scope around.

     

    So it depends what IC's they are. If they are ADC's and DAC's then you'll likely be dealing with I2S/TDM for the audio and SPI/I2C for the control of these. There will likely be an MCU or a small DSP possibly too. I'd say 4-channel or 2-channel + 16 bit MSO option would be a reasonable choice but that does put the price up quite a bit. The 2-channel + 16 bit MSO version of that Picoscope puts the price up to about £380. So at this point the Digilent Analog Discovery 2 is looking like a reasonable option except that the version on CPC Farnell is the basic unit without any of the add-ons so no adapters for scope probes and no scope probes etc. You can get the Pro version from Digilent but I don't know what the cost will be shipped to the UK including any customs charges: https://store.digilentinc.com/analog-discovery-2-pro-bundle/

     

    You could start with a basic 2-channel Picoscope (or something similar) or a 2-channel regular bench scope and see how you get on. You can usually work around the lack of additional channels if you need to and you'd probably be able to resell these if you wanted to upgrade.

     

    Best Regards,

     

    Rachael

Children
  • in reply to rachaelp

    Most of the IC's used in pedal building are OP-Amps like theTL061 & LM741 , and delay chips like a MN3007, SAD1024. There are others obviously, but these seem to be the most common (with the exception of the SAD1024 as that's discontinued)

     

    Cheers

     

    Andy

  • in reply to Andy Betts

    Hi Andy,

     

    Right ok, so if it's all just analog stuff you are going to do, and your audio devices aren't going to involve any digital busses or anything like that then I would suggest you just go for a 2-channel scope. You don't need anything fast, the lowest spec Picoscope would probably do all you need, or get a second hand Rigol/Siglent 2-channel entry level device if you can find one.

     

    The 10MHz 2-channel Picoscope will cost you around £118 delivered from here: https://www.picotech.com/oscilloscope/2000/picoscope-2000-overview

     

    If you want to get a slightly higher bandwidth version you can get the 25MHz version I listed in my first post for around £170. If your budget is tight and you are definitely only going to be working in the audio band then this probably isn't necessary.

     

    Best Regards,

     

    Rachael

  • in reply to rachaelp

    I think either of those will do. The 25MHz version is in budget and would allow redundancy for the future. I may be able to buy that through work as we have an account with Farnell and I wouldn't pay the VAT which is a plus point.

  • in reply to Andy Betts

    If you can buy through work then maybe go to the main Farnell website rather than CPC: PICOSCOPE 2205A PICO TECHNOLOGY, USB Oscilloscope, PicoScope 2000 Series, 2 Channel

     

    Also bear in mind that if you got an entry level Rigol you'd be able to update it to (I think) 100MHz bandwidth. But the starting price point is a lot higher and not in your current stated budget. So I think the Picoscope is still probably still the best option in my opinion. Disclaimer, I don't own a Picoscope and haven't used the software so I don't have first hand experience with these but from what I have seen/read they are good for the price.

     

    Best Regards,

     

    Rachael

  • in reply to rachaelp

    I do own a Pico scope, and a Rigol somewhat up a step from the one Andy can afford, neither of these is my main scope, both were bought for particular applications (the Rigol for use in places where the insurance company wouldn't allow the LeCroy to g !).

     

    I think the Pico stuff that I've seen is pretty good - and I'm very happy with the one I have (5444B).

     

    At Andy's price level not forking out for a screen and front panel makes a big difference to the quality of works that you get.

     

    MK

  • in reply to Andy Betts

    Beware of the hidden horrors with very low cost scopes - for example rarely quoted things like input amplifier overload recovery time (my Rigol DS2072 is pretty poor on this.)

     

    Another thing to watch out for is the offset range on analogue inputs - look for better than 5V offset on the mV ranges - it's often hard to find this parameter in specs.The Pico 2200 range isn't good on this (0.25V), the Rigol 1054Z is much better (2V) (but for twice the money of course).

     

    Finally, with PC scopes the software ranges from really good (LeCroy - whose scopes mostly are PCs) -> pretty good (nearly as good as LeCroy  on the Pico scopes) to really awful (no names to protect the guilty).

     

    For example, IMO the Pico software is the best FFT implementation on ANY scope.

     

    On the other hand all in one scopes are almost all much handier to use.

     

    Can you get a go with a friends scope - if you are ever passing through SW Scotland you can have a look at my scope collection (some still have CRTs).

     

    MK

  • in reply to rachaelp

    That's the scope model I'm considering buying too! I've heard great things about Picoscopes, and I could really do with a portable one to attach to a PC.

     

    A friend is a reseller for the automotive versions (for vehicle repair garages) and he says Picoscopes are the industry leader in that area, and they are reliable.