Do you guys use an oscilloscope?

[Marbles]

Hi guys,

I was wondering: Do you use an Oscilloscope? And if so, how can it be beneficial?

I know that since I'm asking this, it's too soon for me to get one, and I won't be needing it I think (cause I have no idea how). But I read stories of other people saying it's a valuable tool and helps you learn and understand. Whereas others say it's the least used tool and they could easily live without it.

Is it a valuable tool, and how would a beginner use it (besides being something that just sits on a desk and looks interesting).

Do most of you guys use it?

[Ciaran Haslett]

I got my hands on these badduns when our Electrical Engineering department upgraded to digital scopes.  A 2 Channel, a 1 Channel and a function generator with variable power supply, freq counter and DMM.

Truthfully....you can build and debug pedal circuits just fine with nothing more than a test rig and audio probe.  I've been building/repairing amps and synths lately and this is where I think a scope shines.  Calibrating waveforms, searching for noise on power rails/tubes etc.  That's what they were designed for.  I have used a scope on the odd modulation pedal for those very reasons...but 9 times out of 10, an audio probe is simply faster at debugging/tuning.  There's nothing to decipher when using your ears.

The multi instrument on the other hand...I don't think I could build a circuit without it anymore.  The bench power, with built in protection, has saved me so many times from stupid mistakes.  Injecting tones/noise into troublesome vero builds with the function generator has greatly sped up my debugging/tuning.  But again...all this can be done with a test rig and audio probe at a fraction of the cost (well...and a small oscillator build for tone generation)

I made a 555 oscillator here towards the bottom of the page.  It's a great help for getting constant audio into a circuit when debugging.  I'd suggest putting a voltage divider over the output though...it's quite loud and can distort pedals easily.  You could build this into your test box, connected to a multimeter probe and use it to inject audio into any part of a circuit.  Like I said, it really speeds up debugging when you can skip past circuit blocks.

Sorry for the long post but I wouldn't want you thinking you HAD to buy an expensive piece of gear to do all this.  Yes, scopes can be very useful...in certain circumstances...you need to decide if those circumstances will apply to you.

Hope this helps.

[Travis]

Nice setup Ciaran!!

[Beaker]

"Is it a valuable tool, and how would a beginner use it (besides being something that just sits on a desk and looks interesting)."

To answer your questions - no it's not really a valuable tool for pedal building. As Ciaran says, synths, amps and audio equipment, yes. Pedals, no.

They are not easy to use, and take some getting used to.

Yes, it would sit on your desk and look interesting, and make you look like a real boffin.

I've used them at college with students, but they are overkill for pedals. If you get offered one for a cheap price however, why not?

[Travis]

The frequency counter is useful for setting up analog delay and modulation like the ADA Flanger for example

[Beaker]

That's true.

They do have their uses, that's for sure, and for some things they are essential. However they would be way down my list of necessary pedal building equipment.

Would I snap one up if someone offered me one for £20? Oh, yes!

[Silver Blues]

Yeah I've got one. It's definitely not easier than using an audio probe, but it works and I can do it in silence. Old BK Precision analog thing, it does it's job.

[M. Spencer]

Any videos you would recommend to a novice who may or may not currently have an oscilloscope looking cool on their bench?   

[Marbles]

Thanks for all the replies guys!

No need to apologize for the long post Ciaran, it's valuable information! Much appreciated.


Ofcourse I wasn't being serious about looking interesting, it takes up more space than I would like. I need it for, well, organized mess ;)

It's just when googling I read some comments about it saying that after using it people couldn't live without it, or being 'a soldier in the dark' or something like that.

My level is still figuring out what every component in a treble booster does, so a long way to go before I can grasp modulatioon pedals and have a use for this apparently. Amps is even further away.

I think I will wait haha

[cylens]

I'm using a DIY USB kit: http://www.pdamusician.com/dpscope/buy_it_se.html

It's not a "real" oscilloscope, but it's cheap, SMALL and it's been useful on many occasions (calibrating LFOs, probing clock circuits, etc.)

[Beaker]

There's nothing wrong in looking interesting!

Cylens is right though, there are a bunch of cheap pre-built or kit build USB oscilloscopes on the market now. Ebay has loads of them. Not something I had even considered before as I'm used to big analogue cathode ray tube versions.

Like this:

http://www.ebay.co.uk/itm/Hantek-6022BE-PC-Based-USB-Digital-Oscilloscope-20MHz-Bandwidth-48MSa-s-New-/262230322428?hash=item3d0e252cfc:g:kaAAAOSwGiRTrT9N

Some of the kit ones are under a tenner. I might have to look into one myself now!

[PMowdes]

What sort of specs should we be looking for if we are looking for one?

I've seen a few cheap old analogue units on ebay recently but have been put off because I don't know what I'm buying.

[Hozy31]

I have one of these scopes "Hantek DSO2090 PC USB 40MHZ 100MS/s Digital Storage Oscilloscope" which is quite a small box and sits quite neatly on the top of my Scarlett 18i8. I bought it to help calibrate all the modulation pedals i build especially the phasors and flangers. However, i have still never figured out how to properly use it. Anybody found a good guide to there use?

[Marbles]

Oh that's not too bad. Tempting to just try it and see what it does... hm.. :)

I'm curious what kind of specs would be needed as well. You sometimes see them going for peanuts, but no idea what would be minimum specs for useful units

[Ciaran Haslett]

Again...this depends on your application.  But for pedals you should look at a scope with a probe impedance of at least 10Meg ohm.  This will help prevent the scope from loading the circuit you're testing, throwing off the results, with the trade off of lowering the input amplitude.

You don't need the high freq response either.  Most scopes have a 50MHz resolution which is just madness for a guitar pedal.  You'll save a lot of money going for the 10MHz range.

Here is a great read on getting the basics of oscopes.

[Hozy31]

Thanks Ciaran,
Fortunately my scope has a x10 switch on the probe. I think thats maybe were i have been going wrong.
Thanks for the link .

[tabbycat]

re cheapo build-your-owns, i was looking at this a little while ago. i think i may go for it. a mere £20, which is less than a used behringer. for synth building they are kind of essential as it's not always to tell your waves apart in the higher frequencies. this review is the best i found. reviewer seemed very impressed.

https://www.youtube.com/watch?v=TVs8Szdn4eA

[scimitar]

I got one of the £12 kits off ebay, built it in a couple of hours, it taught me how to solder SMD components which wasn't as bad as I thought it would be and it has seen a fair bit of use. I also have a function generator on my phone that is useful but could do with being higher output.

[Ed Nice]

I'm just about at the same place. I'm watching a few on ebay, but I'm still thinking it's just going to be an expensive paperweight unless I move on to bigger audio stuff, which I probably won't. I might just buy one of the cheap Hantek digital/USB setups. Slightly less 'cool', but probably a good starting point.

I suppose, for me, it's that hurdle of moving from observable characteristics, such as using the ear and applied skills for testing and debugging and moving into the realm of theoretical concepts where visualisation based on spectrum analysis, sine waves and even good old equations is far less accessible for a new amateur.  

I also found some decent info here: http://williamson-labs.com/. You need to click 'scopes in the menu as the site is framed.

[Chris60601]

Score from Ebay (minus the toaster oven)

Top left: HP Signal Generator from 1974
Middle Left: Hameg 20 Mhz
Bottom Left: BK Precision 30 Mhz (this puppy was a steal at $18.00)
Bottom Right: BK Precision 30 Mhz

Total investment - Less than $125.00 but it took nearly 3 months :)