Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: tubesornothing on October 27, 2010, 11:48:16 am
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Other than price, what advantages are ther of owning an analog scope versus a digital scope?
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Depends upon exactly what is meant by "analog" vs "digital". If it's just a matter of whether the display (only) is solid state vs CRT, it means almost nothing.
A true digital scope can mean several levels of capability. Storage of waveforms; Triggered storage of waveforms; precise measurement of risetimes and x-axis (eg; time) offsets; much better capability to measure and display jitter; capture, store, and display spurious events that happen only once in a (relatively great) while. I suppose one could really bend their brain to utilize some of the advanced features of a digi-scope but those uses are pretty far off into the ephemeral.
Another potential meaning of "digital" might be that the deflections you see onscreen are the result of A/D converters and NOT analog amplifiers.
Still another meaning might be on-screen display(s) of your current settings of volts/div and sweep times. That's danged nice to have if you are taking pictures, and, speaking of taking pictures, some digital scopes can drive a printer directly to print out what's on-screen, or can "print to disk" to save same.
None of those things are particularly salient to tube-based audio and really anything operating at audio frequencies. It's nice to have minimally a dual-trace scope, and frankly I wouldn't buy a non dual-trace scope. Indeed, the more sophisticated a scope, the more likely you are to have to buy REALLY expensive probes (unless they come with) with eentsy little clip-on dealies that you actually end up breaking by working on tube stuff. At the same time, most probes for 1950's-1960's scopes are like hanging a kielbasa off a component and are cumbersome to poke into compact circtuitry. Not everything is built on a turret board. The point being, if you're paying big bucks for really, really elegant surface-mount probe tips and attachments, those aren't going to do you a bit of good on a 5E3.
The one good thing about scopes for audio is that you can use just about the worst one you can find. (Well...OK, I have a 1952 DuMont 304 scope (Google images) from thegarage of doom that is worth whatever the 3 qty 12AU7's inside are worth) It would nice to have a slick Tektronix scope, say a 2215 - 2245 (there are about 6 models in there) but that $120 Tek scope you buy is gonna cost you dead minimum $500 to fix if you ever need to fix it. I recently bought a Kenwood scope for $140 delivered which I'm pretty happy with, but isn't anything miraculous. I see no reason at all why one would need to spend over $100 on a used scope for audio work. Just be aware that probes can cost and there's nothing worse than intermittent, bad condition scope probes. You can buy import probes for under $15. Real Tek probes are usually in the $100 range all by themselves.
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I've already got scopes. My question was more like: any reason I should keep my analog scopes kicking around since I have a nice benchtop digital scope? Kinda like why an analog meter is sometimes more useful than a DVM.
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any reason I should keep my analog scopes kicking around since I have a nice benchtop digital scope?
Nostalgia, maybe? Actually, if you're only gonna poke around audio circuits, use the scope with the smallest footprint.
I do like knobs though! :grin:
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OK, thanks Steve. I guess both of my Tek 2246's are now on the selling block . I love em to bits, but I need the bench space.
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I guess after this thread, it was only a matter of time! :wink: http://www.el34world.com/Forum/index.php?topic=9667.0
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I see from another thread that you are a "manufacturer". In that case, I'd consider keeping some spare test equipment on hand.
(I have friends who insist on taking 2 compasses into the woods - yeah I know I'm from Brooklyn, NY -- because nobody believes one compass. Can't argue with 2 though!
EDIT: Oh, I see from the Sales page that you already have that covered!
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Yeah, I am a little psycho about scopes. I think they are too cool. I hate to part with them, but need the space.
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Man with 1 watch knows what time it is.
Man with 2 is never quite certain.
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Man with 4 scopes is kinda wierd...
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> Man with 4 scopes is kinda wierd...
I had six.......
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... because nobody believes one compass. Can't argue with 2 though!
I can, and do, function well with 1 compass and a 50,000:1 map, thanks to the Army. Distinguishable terrain and some high ground do wonders.
Somehow, I've wound up with maybe 15 voltmeters of various descritpions, but that's more about curiosity and the desire to tinker...
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Distinguishable terrain and some high ground do wonders.
Right on.
I used to teach mountaineering courses. One of them was wilderness navigation. Nothing worse than being on a featureless flat glacier in a white out. Always nice to have a mountain, or a river visible.
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... because nobody believes one compass. Can't argue with 2 though!
I can, and do, function well with 1 compass and a 50,000:1 map, thanks to the Army. Distinguishable terrain and some high ground do wonders.
Somehow, I've wound up with maybe 15 voltmeters of various descritpions, but that's more about curiosity and the desire to tinker...
It's great to have learned to trust your instruments!!!
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When I was a mechanic,real-time scopes were easier to use than digital ampling scopes and a trained user could spot fluctuations quicker and easier.The digital scope could take a snap-shot of the offending event and store it for you to look at it afterward to determine what was happening.
After a while the scope ended up being left with the cover on it more than it got used.We ended up learning many other techniques for diagnosis that were far easier than even hooking up the scope.And the way the scope was hooked up could lead to mis-diagnosis.
Poor leads,shaky contacts,etc.
For audio it is valuable because there are fewer leads and less to look at.Deciphering what you see is still open to interpretation though.
Your ears and your gut still tell you just as much with a guitar amp.