Should I buy a cheap oscilloscope?

Frequently asked questions about tools and instruments used in stompbox development.
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JiM
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Post by JiM »

Hey, i've found a CHEAP digital oscilloscope, complete or in kit !
It's really basic, and maybe not very accurate, but it might be enough for stompbox debugging if you're afraid to fry your soundcard ...
http://www.nkcelectronics.com/digital-s ... -cost.html
http://www.nkcelectronics.com/digital-s ... y-kit.html
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Post by analogguru »

That´s really a nice piece, enough for stompboxes.
What is not mentioned is if in the kit the case is included.
Another "minus" is that there is obviously a pc-connection possibiilty, but probably the stored data can´t be uploaded to the pc, what would be great.

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Post by JiM »

It looks like the panels are not included with the kit version, only the assembled version. But you can buy them separately from the factory : http://www.jyetech.com/en/default.html
Or get a kit with panels here : http://www.seeedstudio.com/depot/digita ... p-166.html

About PC interface, there are instructions for uploading the firmware over SPI or serial (UART/TTL) ports. One could imagine an alternative firmware with data upload over serial port, or waveform storage on SD card over SPI ...
Unfortunately the firmware is not open source :(

An interesting review : http://www.arduino.cc/cgi-bin/yabb2/YaB ... 1228070870
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Post by FearlessFlyingFrog »

Hi,

I've been thinking about ordering one of these for a while, now.
While this certainly is inferior in many ways to a "real" analog workbench unit, I wonder if the more experienced guys here could tell me whether the limited bandwith (1 Mhz) and Sample Rate would be sufficient for stompbox use (e.g. setting a flanger/phaser/delay unit etc.)
And what, when it comes to debug guitar amps?

Linkie:

http://www.seeedstudio.com/depot/dso-na ... l?cPath=11

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Post by Silent Fly »

I must say it does look cool.

You may find this review useful.
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Post by jrod »

That's really cool!

Here is another cheap one: http://www.dpcav.com/xcart/product.php? ... 1&featured

I am wondering if either one would work for calibrating an Aqua Puss!?

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Post by FearlessFlyingFrog »

Silent Fly wrote:I must say it does look cool.

You may find this review useful.

Thanks.

Indeed, this is very useful.

It's a hassle to get it to Europe though. High shipping charges and I assume there will be additional customs fees.
A second channel would be great, also. There is the option to store the first wave and compare it to the second, though.

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Post by ckyvick »

jrod wrote:That's really cool!

Here is another cheap one: http://www.dpcav.com/xcart/product.php? ... 1&featured

I am wondering if either one would work for calibrating an Aqua Puss!?
you can use a simple audio probe to calibrate the aqua puss, check out the byoc delay instructions

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Post by modman »

https://www.freestompboxes.org/viewtopic.php?p=33880#p33880
There is also a link to a free software scope in that thread, though I haven't tried it myself.
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Post by yahoo! »

does anyone how to use a oscilloscope in developing/modding/debugging a certain pedal?? :?:

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Post by Dirk_Hendrik »

yes?
A scope is used to verify signals available at the places in a circuit where they are expected. When you know what signal in what magnitude should be at a certain node you check this on your scope.
Sorry. Plain out of planes.

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Post by yahoo! »

Dirk_Hendrik wrote:yes?
A scope is used to verify signals available at the places in a circuit where they are expected. When you know what signal in what magnitude should be at a certain node you check this on your scope.
i have a old tektronics 2213. does my device meet upon a certain work?

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Post by mictester »

yahoo! wrote:does anyone how to use a oscilloscope in developing/modding/debugging a certain pedal?? :?:
All the time. A good 'scope is like being able to see what's going on in a circuit. I find it to be as useful as a multimeter!
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Post by modman »

I merged some oscilloscope threads into this one, now for the time being in the FAQ root folder. When moved to the subfolders discussion is no longer possible. You guys can still reply here, no?

I think I paid some 75EUR for my oscilloscope on ebay, Goldstar OS9020A 20Mhz dual channel.
Image

I just found out even famous people use this exact scope, so should be good enough.
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Post by DrNomis »

If the Oscilloscope ie in reasonable condition,by all means buy it,actually,buy yourself a couple,you can never have too many Oscilloscopes,I bought myself a nice little 10Mhz single trace Scope from Dick Smith Electronics for about $125.00,10Mhz is good for audio work,if you intend to do some work with digital ICs,try and get yourself a Scope with alot of bandwith,something like a 100Mhz dual-trace,since they will have enough bandwith to be able to display spurious spikes and other glitches,yes I know,they are more expensive..... :)


Also buy yourself a good Signal Generator or Function Generator too.... :)
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Post by Tonetweaker »

I was recently in the market for a new scope to upgrade the one currently on my workbench since I've decided to get back into effects building... There are a lot of nice ones suitable for audio electronics on eBay right now at fairly reasonable prices, but make sure to get one that's tested and calibrated.

I ended up buying a Tektronix 2446 for a great price (150MHz, quad trace... overkill for audio electronics, but I get asked to troubleshoot all kinds of stuff).

I also picked up a new Fluke 77 MM, Wavetek signal generator and a new Weller soldering station (variable), which is more suitable for PCB building. Ironically, all of this stuff is the same equipment we used in the military (I was a radar tech) for troubleshooting and repair. I guess I'm a creature of habit, but I also figured that if this equipment can be used to work on a high-powered radar system, it'll probably help me out when I'm trying to figure out how I screwed up the wiring on my latest contraptions too... :lol:


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Post by ganzziani »

Image
I have developed a very cheap multifunction device: it is a mixed signal oscilloscope with 2 analog inputs and 8 digital inputs, and it has an integrated waveform generator. It is tiny (1" x 1.6") but it has a ton of features. The device comes in a DIP module, it is meant to be used directly on a breadboard, or can be embedded in another project. You can find specifications, documentation, and videos at the product's webpage: Xprotolab.

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Post by robinbowes »

Hi,

I fancy picking up a 'scope to do some measurements, check waveforms, etc.

Anyone care to point me at a good, cheap one? I'm happy to pick up an older second-hand one. I'm in the UK.

Ta!

R.

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Post by DrNomis »

robinbowes wrote:Hi,

I fancy picking up a 'scope to do some measurements, check waveforms, etc.

Anyone care to point me at a good, cheap one? I'm happy to pick up an older second-hand one. I'm in the UK.

Ta!

R.

For general work measuring signals in audio equipment I would recommend a Scope with a bandwidth of anything from 5 to 20Mhz, a Scope with a single trace is fine, but if you can afford to buy a Dual-Trace Scope and in good working condition, buy it, the extra trace comes in handy when comparing input and output signals... :hmmm:

The new Digital USB Oscilloscopes are cool, you can save pictures of what you see on the screen to your computer's hard drive, so they're worth considering... :hmmm:

Here's a pic of my two Oscilloscopes sitting on my workbench, I bought them from Dick Smith Electronics when they sold electronic parts, the smaller Scope on the top is a 10Mhz Single-Trace, and the larger one on the bottom is a 20Mhz Dual-Trace, the 10Mhz Scope cost me about $125.00 Australian, the larger one cost me $740.00 Australian when I bought it new back in 1997, they have since gone down in price, both Scopes are Analog:
Attachments
My Oscilloscopes
My Oscilloscopes
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Post by JudgeMingus »

My 2c...

You don't need to spend much at all if you look around - I scored a single-trace BWD 509B for AU$26.00 (plus a 50 minute round trip to collect) on Ebay recently.
It is a locally made analog scope (they were widely used in Melbourne schools in the '80s), which I got without probes - I am currently just using multimeter ones (OK enough for my current use) until I get around to buying some proper ones, which will probably cost more than the scope itself!

The scope works fine and does all that I will likely ever need for analog audio - a second trace would be nice, but isn't vital.

If you do buy on Ebay, buy from someone close to home, who specifies in the description that the device is tested and working - that way you can pick the device up (avoiding post costs and risk of damage) and have recourse if it turns out to be faulty.

There are quite a few ads for non-working scopes and these should be avoided unless you really want to rebuild an oscilloscope for fun...

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