Billy Zoom's Jet Set

Looking for a decent analog scope.

1

Mr. Zoom,

As you had said, Dailey's book is good and has served as an excellent road map for my own studies related to electronics.

I'm in the market for a decent analog scope I could work with. I could go digital (Rigol DS1054Z looks good), but I'd rather start out with something that doesn't have tons of menus and push-button rotary encoders.

Analog scopes also look cooler on a bench, but I digress.

Do you -- or anyone else on this forum -- have any suggestions regarding makes, models and MHz? What should I look for if I'm going to be working with audio effects and amplifiers?

2

For debugging audio circuits, you'd want a scope with at least 2 channels. 10MHz should already be enough to cover your needs given the limited audio bandwidth (plus it'll let you see RF range oscillations).

When you intend to work on tube circuits, check the input ratings of the scopes your looking at. Many modern digital scopes have something like a 100V or 200V max input rage. That is not sufficient to work safely on tube circuits. Look for one with a minimum of 400V rated input (without x10 probe) - 600V would be even better, but those are much harder to find.

I'm using a tektronix 2225 - it satisfies all my regular needs, although I've come across the occasional situation where I'd like one or 2 channels more. Picked it up for €75 used.

3

Just checked the specs on the Rigol you mentioned.

That's a heck of a lot of scope for the money!

Input ratings puzzle me a bit:

Max Input Voltage (1MΩ) Analog channel: CAT I 300 Vrms, CAT II 100 Vrms, transient overvoltage 1000 Vpk With RP2200 10:1 probe: CAT II 300 Vrms Digital channel: CAT I 40 Vrms, transient overvoltage 800 Vpk

This suggests to me it'll take 300V straight up on the analog input. Transient overvoltage tells me it'll take 1000V only very briefly.

4

Michiel, that looks like a nice scope -- and it is not hard to find one in nice shape at a decent price on eBay. Thank you for that suggestion. I'm looking more into it now.

And yes, that Rigol is tempting! Heck, at the prices analog scopes are going for on ebay, I might have enough to buy a Rigol as well.

6

Digital scopes are a total waste of time for analog work. I haven't even turned mine on in nearly a year. FFT was interesting for a few days, but not really useful in the long run. Experience is the best teacher.

7

I got a Hameg. It's two channel. You want two channel. It has no smd parts inside. Very important if you want to repair it. I know Kenwood scopes have nasty smd modules inside. Mine has a digital sampling circuit which can make snapshots and do slomo like tricks. I have used those tricks quite often. I would recommend to go to at least 20Mhz. It was the norm when I tried to learn about electronics. Mine can't take high voltage at the inputs. Michiel is right: you want high voltage capabilities. But practice with low voltage circuits first: pain or death can terrible to experience. You may want some extra connection stuff with croc clamps and banana connectors, since the fiddly probe connectors often unhook themselves. I paid a a massive amount of money for my scope many years ago. Unfortunately I'm too stupid for electronics so it was a total waste. Luckily you can try if you can do this, for a lot less nowadays. I would say go for it. (smoke and/or flames often indicate something went wrong)

8

 photo 1294009341.jpg I got this for free years ago. Single channel correct, and if so what's it good for?

9

Don't stick the probe where there's high voltage. There's rarely a need to, and if you really need to, you can clip a cap on the end of the probe, or solder one end of a cap to that part of the circuit if you plan to go there a lot. I think I currently have four B&K's, two Tektronix, a Hitachi, a Heathkit, and a B&K Digital scope. I use the cheap 15meg B&K 1477 98% of the time. I've had that one since the early 80's. The older B&K's are much better than the later ones. Just don't go much earlier than mid-seventies because the scopes were too primitive. You want a dual trace and the most sensitive setting should be .01v/cm. Some of the newer analog scopes won't do that, and you need to be able to look at guitar level signals with good resolution. You'll probably need new probes, and they'll probably cost more than the used scope, but you should be able to find a good deal on a pair on Amazon.

10

http://www.ebay.com/sch/sis...

Those later ones like the 2120 aren't very good, but I carry one in my toolbox on the road because I don't care much what happens to it. The 30 meg 1479 is a good scope too, but seems to require periodic maintenence. All I've ever done to the 1477 was to leave it turned on 6 days a week for years and years. Of course, an old Tektronix is a great scope, but they're always more expensive and more used. I assume you know you'll need a signal generator and a dummy load to do anything with the scope.

11

I'm trying to recommend very inexpensive solutions. If you can afford fancier stuff, go for it.

12

Inexpensive works for me. I was planning on spending a few hundred dollars. Thank you very much for all the help. Now off to find one that works!

13

You should be able to get the scope, probes, signal generator, dummy load, and a meter for that. Then look for a copy of the old Jack Darr book.


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