Recommendations: Cheap Oscilloscope?

[tmbg]

that's the suck part about ebay, you so often get scopes without probes.

Probes (good ones at least) are the expensive part!

 

[NewYorkDave]

I completely disagree with the assertion that a 1MHz scope is "good enough." You would be amazed at how much phenomena you can find above 1MHz in nominally "audio" circuits, especially when they're misbehaving. I recommend a specified bandwidth of at least 10MHz.

The 453 and 454 are OK scopes when they're working--if you don't mind the tiny screen--but forget finding parts for them if they fail.

I used to recommend the 465 series. While I still think it's a fine scope, it's getting old and parts and support are not as readily available as they used to be. Nowadays, I would suggest something like the 2235 or 2245. We have 2235s at work and they're great general-purpose scopes.

When it comes to scopes, I'm definitely a Tektronix man.

 

[tmbg]

Teks are definitely the stuff, but they're expensive for anything remotely modern. In the past I've felt like buying a $50-100 philips scope was better than buying a $50-100 tek. But now I've broken down and bought a $400 Tek. I just hope it F&!%#@ gets here!

I HATE FEDEX

 

[NewYorkDave]

I used a Phillips scope when I worked at a Hi-Fi repair shop and I have no complaints about it.

 

[tubejay]

[quote author="tmbg"]but I'd be happy to help you find a nicer one on ebay. What's your budget?[/quote]

I'd love to see what you or anyone else who's willing could find me on eBay. Sceneria had done that for me a while back, and then I ran out of cash before I could buy one. That's why I don't really want to wait any longer to buy one. I know I'll find something else to spend my money on. I'm already looking at some PCB's over in the black market, and practicing as much restraint as I possibly can.

My O-scope requirements are that it's full functional, and hopefully has probes. However if I can get buy with buying some cheap probes, that's fine too. I'd like to spend under $100 including shipping. At this point, I'm not even sure how much I'll use it. If I find that I use it all the time, then I'll upgrade. If not, well then I'll just use it when I run into trouble. I'd also like to be able to have the manual or be able to find one online. All of the Tektronics stuff appears to be out there, that's one of the main reasons I was sticking with Tektronics. However, if I can get a manual, and it's a decent enough scope for audio, I don't care.

I'm pretty new to using O-scopes, so this is going to be a learning experience for me. Aside from checking my projects to make sure everything looks right, I don't know what else I would use it for. So as long as it does all the stuff I need for audio, I could care less about anything else.

What does screen size do for you anyway? I ask my wife similar questions all the time. :roll:

 

[tmbg]

this might be a tad outside your range, but if you can snag it, wow!

Not exactly what you're looking for, but neat stuff

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=45007&item=3853441020&rd=1

As far as screen size goes, bigger the better of course. You just don't want to be squinting trying to see whether or not your triangle wave is slightly distorted, or whatever

 

[PRR]

> I completely disagree with the assertion that a 1MHz scope is "good enough." You would be amazed at how much phenomena you can find above 1MHz in nominally "audio" circuits, especially when they're misbehaving. I recommend a specified bandwidth of at least 10MHz.

Hmmmm. I still use this piece of 1946 high-tech:

Note that it calls itself an oscillograph, not oscilloscope. Same thing, but the concept was so new that "'scope" hadn't become the common name yet.

Probably once hit 400KC (though certainly would not lock that fast!). I got it with much of the guts ripped-out, so I re-built it simple and cheap and sand-state. LM324, 555, two TO92 transistors. 20KHz bandwidth.

Some guy in Ontario wants $90 for his DuMont 164, as-is, "collectable".

No, I don't really suggest this as a bench-scope. I also have a "20MHz" scope and even that does not always resolve oscillations in "tame parts" (TL072 and PN3055). But at least the 20MHz shows fuzz: the 20KHz scope won't.

The so-called 20MHz is a Leader from the 1980s. Mostly I am quite happy, but for the last 15 years the power supply has been sagging. I re-trimmed the regulators a little lower to keep it working, but it isn't nearly as over-built as a Tek.

 

[tmbg]

my main philips has been acting weird lately, it shows a pretty significant ripple even when the channel is grounded at the scope, or with the ground button in on the scope. Is that a power supply issue?

 

[clintrubber]

Don't know how many channels your Philips has, but are all channels acting the same here ?

 

[tmbg]

it's 2 channel, and yeah, both channels have a ripple riding on whatever input signal you feed it, even ground.

 

[tubejay]

Ok, let me ask it this way, if you had to choose between a 453 and 454, which one would you choose, and why?

Thanks again for all of the input, this is very helpful,

Cool scope PRR!

 

[tmbg]

They both look about the same to me physically, except for the badass blue screen on the 454

What's the specs between the two?

 

[tubejay]

I have no clue what the spec differences are. I wouldn't even know what I was looking at if I did. The only thing I gather thus far is screen size, and MHz differences. The 453 is 50MHz. The 454 is 150MHz or so says eBay.

Other than that, I know not. I just saw a nice 453 with a bunch of probes for $75 that looks kind of tempting.

Here's an auction with a very good description of the 454:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=45008&item=3852742364&rd=1

 

[tmbg]

I'd say they're probably both Just Fine. 50MHz is plenty for audio work, for sure. The fastest scope I have (not counting the one still being kicked around by fedex) is only 50MHz.

 

[tubejay]

Thanks again everyone, I went ahead and got a 453 that was in great shape with lots of probes. Hopefully it will last me a few years, or at least long enough to figure out what the hell I'm doing with it.

Thanks for all of the input!!

:grin:

 

[tmbg]

It may be too late, but one thing you might want to look for is whether it'll do X/Y mode, which is where the timebase quits sweeping, and one channel controls vertical deflection, one controls horizontal deflection.

THEN, what you can do is get a function generator that does lin or log sweeps, and you connect the sweep ramp of the function generator to the horizontal deflection channel, and the function output to your audio circuit, then the output of your circuit to the vertical channel on the scope. Now, your scope will draw pretty frequency response graphs for you!

 

[clintrubber]

my main philips has been acting weird lately, it shows a pretty significant ripple even when the channel is grounded at the scope, or with the ground button in on the scope. Is that a power supply issue?

Do you have access to another scope to probe a few points (supplies etc)in the S.U.T. ?

BTW, for some reason this brings to mind the story of someone at work who repaired a faulty scope-channel by using the rest of the (obviously multi-channel) scope ! :wink: :grin: :green:

 

[tmbg]

I'm sure I can dig up something My new digital scope SHOULD be here tonight, so yeah, I can trace the scope

what should I look for?

 

[tubejay]

[quote author="tmbg"]It may be too late, but one thing you might want to look for is whether it'll do X/Y mode, which is where the timebase quits sweeping, and one channel controls vertical deflection, one controls horizontal deflection.

[/quote]

That sounds awefully fancy! :razz: I'm not sure if it does X/Y, and yes it is too late. I bought one. I'm in the process of downloading the 76MB, yes, that's 76MB manual. It should be done in about 45 minutes. The server that I'm connecting to seems pretty slow.

I'll let you know if it does X/Y.

 

[tmbg]

Where'd you get the manual?

I really want to get a manual for my 2230, but they're hard to find