Which Oscilloscope is the one to buy?

[Brymus]

Well didnt get any response in Devis thread so I started one for myself.
I really want to get an Oscope this year so-
A few questions >
1) E-bay has lots of used scopes for around 200$ that would appear to be in the 600$ range new is this a good route ? > buying one on the bay.
   most don't have leads or manuals...

2) For building pedals I am guessing the 60$ kit one that Scruffy linked to would be fine(same one on the DIYstompboxes homepage) ,even though its one channel,would this work for all pedals >flangers ,envelope filters ect... ? (IDK nada about using a scope but plan to learn this year)

3) The one Scruffy linked to only works up to 50V p-p so tube amp work is out > correct ?

4) As I can already say I am quite serious about learning the methods for repairing and designing Amps,and other electronics,I would like
  to eventually work in a related field.
What are the features >requirements I should be looking for in buying a scope that will work as I evolve and learn more ?

5) Could someone break it down like this with the features to look for/that are neccesary ?
                                                           > USB PC scopes in the 100- 200$ range (how useful are these?)
                                                           >scope for pedals only (the 60$ kit ?)
                                                           >scope for the majority of audio/hobby related work,amps,pedals,ect
                                                           >scope one would need when applying for a general electronics service/tech job

I think the answers to these questions will be quite helpful to anyone interested in buying an o-scope.
So thank you in advance for your help/replies -Bryan

[G. Hoffman]

Well, I haven't got it yet, but I just ordered on of THESE the other day.  It is the same one Weber sells (they are out of stock, or I would have ordered from them), which Ted Weber said was all he ever needed for audio work.  I figure he knows more about this than I, and other people I trust have agreed with him.  More expensive than buying a used one on ebay, but I like the confidence of getting it from a known source, and I like the fact that I can get a warranty on it. 


Gabriel

[Brymus]

Well, I haven't got it yet, but I just ordered on of THESE the other day.  It is the same one Weber sells (they are out of stock, or I would have ordered from them), which Ted Weber said was all he ever needed for audio work.  I figure he knows more about this than I, and other people I trust have agreed with him.  More expensive than buying a used one on ebay, but I like the confidence of getting it from a known source, and I like the fact that I can get a warranty on it. 


Gabriel

Thanks for the info Gabriel  ,yeah Ted seemed like a pretty smart fellow RIP.
But for the price an extra 40$ would get you another channel and a signal generator from the one in Devi's link.
Its all really confusing to me especially since I have never even used one.
Maybe some others will chime in,I know alot of the forum members use scopes.

[G. Hoffman]

I've heard some pretty reasonable arguments for PC based O'Scopes being less than a great idea - primarily to do with the need to interlace the test signal with the sample rate of the PC, and the possibility of false reading resulting.  Probably, none of those are a big deal for the audio frequency issues we deal with around here, but you are also dealing with a immature technology, which always makes me less than enthralled with an idea.  I KNOW that any analog scope will easily handle any of the work I want to do.  I believe that a PC based scope will handle any work I want to do. 

At least, that is my reasoning.  But I haven't used a scope more than a couple times in my life, and those were all a part of some assignment or another in college.  And honestly, the one I remember doing was over-shadowed by the next assignment, where I learned to cut tape!  (Cutting tape was way more fun than digital editing, by the way - it just doesn't work nearly as well!)


Gabriel

[Ibanezfoo]

I use an analog 2 channel 20mhz scope I got off ebay for 10 bucks.  Works great!

[Brymus]

Thanks ,Gabriel-Foo...
Any one else ?
Come on you guys/gals that use scopes,share your wisdom here...
PLEASE ?

I would really like to hear all advice on this in order to make at least a semi informed desicion on purchasing one.
At this point I am leaning towards a USB one for the price point alone.As I have an older PC I could use for that purpose.
(thanks RG)

[Mojah63]

You really don't use them a lot BUT when you need one to see whats up they are indispensable...

Unless your doing rf work I wouldn't sweat the mhz rating... Audio maxes out at 20k.. Dual or single... I never use the 2nd channel doing amps or pedals... 2nd channel may come in handy doing digital stuff with clocks.

I personally wouldn't spend more than $125 for a used one.. I have a nice Tektronics one at work and a junker at home... You can use a voltage divider to up that 50vpp diy scope you mentioned to see more voltage, or use a probe that has one built in (most do have a 10x)...

Try to find a ham swap or a big flea market and bring some cash... 

or Ebay:

http://cgi.ebay.com/LG-GOLDSTAR-OSCILLOSCOPE-OS-7020A-20MHZ-7020A_W0QQitemZ110489823939QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item19b9b4eac3

[sundgist]

I'd have a look on ebay. There's always a steady flow of used scopes for sale. Transistor built analogue scopes from the late 70's onwards can be had for silly money and are pretty much bulletproof. Just make sure the CRT has a good sharp focus and is bright and make sure you ask whether there are any problems. Again, there's a steady flow of these so avoid any that look dubious, have vague descriptions or if the price goes up above the max you want to pay. Take your time and pick up a bargain. I'm in the UK, so whatever the exchange rate is, I would probably pay £80 max for a top condition 100Khz 2 chan scope from the early 90's, £40 max for any top condition 2 chan scope from mid 70's to 80's. Anything earlier or valve powered has to be special.

I got myself a nice HP 1740A 2 chan 100khz analogue scope for £30 which has features that are way in excess of anything I need, but are nice to have all the same. I just did a bit of research on what was on offer and checked for availability of manuals and schematics (just in case) on the web.
I also bagged a faulty 2 chan 20Khz Kenwood CS-4125 for £1 which is under my workbench awaiting some new parts and a single channel valve powered portable scope with frequency generator and a bipolar 9v power supply which works beautifully ("generatorscope" it's called!) for £16. That's pretty much a self contained stompbox testing kit.

In answer to your questions, excuse my own personal bias:
1) as above. Most manuals can be found online from the manufacturer or otherwise. There are probably less than a handful of manufacturers that use their own proprietary mains leads, most use standard plugs. Probes can be bought cheaply enough. Again a bit of quick research helps here.

2) For the price and the comfort of a warranty, can't really go wrong there. It looks like it's cheaper now.
http://www.dpcav.com/xcart/product.php?productid=16330&cat=0&page=1&featuredG
Good to learn the basics on. Once learnt, if you feel the need to upgrade, I'm sure it will still have it's uses due to it's portability. Personally I'm not won over by the resolution of the screen. Dual trace is useful as you can compare two signals on screen at once ie. original signal and effected signal. For the same price you could get a used 2 channel scope that shows sine waves without the steps and will do anything you need it for in the future.

3) Unless you use an appropriate wattage voltage divider.

4/5) I found using an analogue scope made understanding what I was doing and seeing a lot easier. For audio and most basic work a decent 2 channel 20Khz scope will be all you ever need. The only time I would use a pc based scope would be with my laptop if I needed one out on the road doing field work. Better than handheld LCD screens, but in the lab/workshop definately still a good standalone analogue scope.

[G. Hoffman]

Unless your doing rf work I wouldn't sweat the mhz rating... Audio maxes out at 20k..

First, I'm not disagreeing with you, and frankly 20K is kind of optimistic for most people's hearing.  By the time you are 20, most people have a hard time hearing much above about 13K.

Still, that doesn't necessarily mean that's all you want to check. 

I worked security for a thing George Martin did once.  This was shortly after he retired, he had put out a book about the making of Sgt. Pepper, and he was doing a publicity tour.  One of the things he discussed was a thing that happened at AIR studios in back in the `70's.  They had a brand spanking new Neve console that was the cleanest, best console the world had seen up to that point.  Nice piece of goods.  But Martin's engineer, Geoff Emerick, thought one of the channels sounded weird.  No one else noticed it, but he kept saying it was wrong.  Neve sent over a tech who checked everything over, ran through the whole audible frequency spectrum and it looked exactly the same as every other channel.  Nothing wrong.  So they lived with it, but within a week Emerick was complaining again.  This time, Rupert Neve himself came over.  They ran through all the frequencies, and still couldn't find anything wrong.  So they tried extending the frequency range they tested.  On that one channel, there was an odd distortion at 150K on that one channel, and none of the others.  So, they swapped out the channel for a module that didn't have the 150k distortion, and Emerick was happy. 

Now, this is not to say that people can hear anything at 150K.  Its not even to say that Geoff Emerick can hear anything at 150k.  But, things like that can have some parasitic effect on lower frequencies.  So while you usually don't need to concern yourself with anything above 20K, there is always information up there. 

Then again, none of us are building $100,000+ analog mixing consoles, so our level of perfectionism is a bit lower.  At least, I assume we aren't.  Still, it's an interesting story, and I've since read both Geoff Emerick and Rupert Neve talking about it, so it seems to have a significant level of believability. 


Gabriel

[R.G.]

Picoscope 2203

http://www.picotech.com/ultracompact-oscilloscopes.html
5MHz bandwidth, two independent channels, arbitrary waveform generator (that's a test signal generator!) built in. $263.00.
Software to capture the scope traces, record both the traces and the raw measurement data, do frequency spectrum analysis, autoranging, and much much more.

About the only limit that makes me go back to a hard scope is the 20V max on the inputs.

They just work. An old, ready-to-toss laptop works fine. Much smaller and more portable than even a "portable" hard scope.

[sundgist]

""5MHz bandwidth, two independent channels, arbitrary waveform generator (that's a test signal generator!) built in. $263.00. Software to capture the scope traces, record both the traces and the raw measurement data, do frequency spectrum analysis, autoranging, and much much more.""


That sounds pretty much complete. If only I had the cash.

Ah but I'd miss the mad proffessor bank of test equipment the soothing HV hum and those hypnotising green glowing traces!

[Nikolay]

Get some old tektronix. 2x40 or 2x60mhz

I use it Tektronix 2215A

old scopes are a bigger, but they are better than a new cheap digital.

analog scopes have 3 disadvantages: They are big, In low frequency it is not so good to see what's happen. not all scopes show period, Vpp and other usefull info.
If you like to use 2channels in high frequency get the scope without chop function. If you use it for normal audio this doesn't matter

[Brymus]

Thanks for the replys !!!
That helps alot ALOT.
I was gonna get that one for 59$ in the link above, tommorow,(when I get some $) but someone already bough it today 
I think I will look for a decent used Tektronic,maybe get the 60$ DIY one ,or a USB scope,just gonna have to look at whats available.
I think the DIY one,or a USB scope would be good to start on and learn how to use one.
If I cant find a decent used one on E-Bay.
Again thank you ALL who replied,(Gabriel,Sungisdt,RG,Mohjah63,IbenezFoo) I very much appreciate your time here.
Bryan