Don't forget that you likely need to add probes if you buy used. Don't go too cheap here. The last thing you want is a flaky probe. Ideally buy a scope that comes with probes. You don't need anything fancy. A plain 10x (or 10:1) probe is what you want.
Tom
Tom
Totally agree. The entry level of this 12-bit series, the 802X 70MHz, costs just $339.00 (more than enough for audio).
And the SDS812X HD 100MHz, costs $439.00.
This is a very nice tool to have and covers all you need for audio.
Maybe adding the high voltage probes for tube working as mentioned.
Look at the manual for checking the accessories and functionalities:
https://siglentna.com/wp-content/uploads/dlm_uploads/2024/10/High-Resolution-Oscilloscope-Guide.pdf
Now you have a very good option here @blue360cuda
I'd say that the biggest danger of digital scopes is the AUTO SCALE button. If you're looking at a pretty signal, auto scale tends to work well. But if you're looking for something that's a bit more out of the ordinary, auto scale will often turn your scope into a slot machine. You might win, but odds are low.
If you end up with a digital scope, I recommend that you learn how to use the trigger. Basically, study the fundamentals of how a scope works and go from there. Understanding how the scope works will help you when auto scale doesn't.
Tom
If you end up with a digital scope, I recommend that you learn how to use the trigger. Basically, study the fundamentals of how a scope works and go from there. Understanding how the scope works will help you when auto scale doesn't.
Tom
Yes, the Siglents come with probes. They also come with a warranty! I use a lot of 8-bit Tek scopes at work and an 8-bit FFT is near to worthless. At 12-bits the FFT is quite usable. The noise level of the scopes is good, though not the equivalent of my 1A7A differential plug-in in the 500 series tube Tek or similar plug-ins for the 7000. That's really the only thing I miss, and I can always build a preamp if needed. The other thing you get with these scopes is about a dozen different ways to trigger, though for audio you rarely need anything special. There is a learning curve and I always keep a rubber tipped stylus handy (attached on a string!) because my fat fingers are a bit large for the touch screen.
Agree with Tom, I never use auto. It lands in a space with everything wrong usually. I usually know what I am looking for and set trigger, sweep speed, and voltage range ahead. And with the digitals, trigger comes in many flavors not available in analog. Like pulse width < 1uS etc instead of just rise/fall. I use triggers like that to find impossible to find issues all the time. I'd encourage you to download some manuals and while difficult to digest, think to yourself of cases you'd want to probe. Then think how would I set the trigger, sweep etc. One last point and not to be political. In the current climate, I'd suggest soon. All those low priced scopes are made where you expect, even US brands, and they could be going up significantly in a couple weeks, days, hours. Oh, one other thing you may want, some of the latest scopes are powered via usb-c, which means running off a battery becomes a possibility.
Yep. Fancy triggers like protocol trigger and "trig on oddity" are definitely handy at times. As is the line trigger. I use that a lot when debugging hum issues or measuring ripple voltage.
Tom
And there are situations where you don't want any trigger, such as observing a slow non repetitive signal.
We need to know how our measurement instruments work and what are their limitations to get the best from it and get an accurate result.
We need to know how our measurement instruments work and what are their limitations to get the best from it and get an accurate result.
There Tek 2215 is a good starter-scope, but you must see and test it in person before purchase -- just connect the probes to the calibrator and make sure that they square wave isn't distorted. A good place to look for info on Tek scopes is the tekscopes@group.io
The basic scopes from Sigilent and Rigol are very good.
Me, I have a Tektronix 2465B, 5223, and 7704A, as well as a Sigilent and Lecroy.
I guess first and foremost, what will you be measuring? If it is tube based gear, pay particular attention to the input voltage ratings of the scope direct, and the probes.
For me, getting the job done is the most important. Bell and whistles are things you don't often use. Maybe never, but they sure sound good. I love the analogue scopes because you turn them on, and start working. I work a lot on control and digital signals, mostly analogue. I'll take a good analogue scope any day over my $25K Keysight MSO. That is a wonderful instrument and I love it. But, if I was only working on analogue stuff I'd take an older analogue hands down. I do a lot of digital and for decades was able to do it with an analogue oscilloscope. Decoding serial data is not something you do much of.
For what it's worth. I find it too easy to get attracted to features, bells and whistles when the core function isn't as good.
By the way, "autoset" works great on the Philips PM 3070, the Agilent 54642D and the Keysight MSOX3104T. But advanced triggering should be understood. But always remember, a DSO is a sampling system, it is not the same as an analogue oscilloscope. Sampling systems will merrily lie to you under the right circumstances.
For me, getting the job done is the most important. Bell and whistles are things you don't often use. Maybe never, but they sure sound good. I love the analogue scopes because you turn them on, and start working. I work a lot on control and digital signals, mostly analogue. I'll take a good analogue scope any day over my $25K Keysight MSO. That is a wonderful instrument and I love it. But, if I was only working on analogue stuff I'd take an older analogue hands down. I do a lot of digital and for decades was able to do it with an analogue oscilloscope. Decoding serial data is not something you do much of.
For what it's worth. I find it too easy to get attracted to features, bells and whistles when the core function isn't as good.
By the way, "autoset" works great on the Philips PM 3070, the Agilent 54642D and the Keysight MSOX3104T. But advanced triggering should be understood. But always remember, a DSO is a sampling system, it is not the same as an analogue oscilloscope. Sampling systems will merrily lie to you under the right circumstances.
Again, all great knowledge, please keep it coming!
I see some of the models have built in signal generators - seems like a worthwhile feature for audio, yes? Or is a standalone unit a significantly better option when needed?
From my first look through it seems to be coming down to Sigilent and Rigol. Found some interesting comparisons between the two- no clear winner but Rigol seems to come with nicer probes?
I see some of the models have built in signal generators - seems like a worthwhile feature for audio, yes? Or is a standalone unit a significantly better option when needed?
From my first look through it seems to be coming down to Sigilent and Rigol. Found some interesting comparisons between the two- no clear winner but Rigol seems to come with nicer probes?
Standalone is better, since sometimes, ground is not the same - E.g.: amp in bridge mode output.
Built in generator will have common ground with scope.
The signal generator is only useful if it is an arbitrary type that will replay a captured waveform. Even then, only useful for special waveforms. For audio, generate from a sound card where you can get sine and two sine out for distortion testing. For general stuff I like a function generator where you can reach out and twist a knob. Easier and faster. I tend to use my RTX audio analyzer, but otherwise I'd use the oscillator in my HP 339A.
The problem with built in stuff is the number of menus and keystrokes to set it up. It's a pain and if you use it a lot, you'll probably grab an external source. My scope has one, I only use it for special circumstances.
The problem with built in stuff is the number of menus and keystrokes to set it up. It's a pain and if you use it a lot, you'll probably grab an external source. My scope has one, I only use it for special circumstances.
Agree! It is an addition reason for not using scope built in signal generator.
I want to observe the signal in the scope (so don't touch the scope) while I change things somewhere else such as the signal generator, power supply, load etc.
The sucker punch for a modern digi scope is real-time RMS and Peak readings for each channel. I need to sell off some of my analogue scopes, as I have more than I will ever need (numerous Tek 7000 mainframes). The analogue scopes are way more fun and educational to use, but I find my digital Teks get far more use, simply because of the real-time DVM reading. Of course, you don't need a DVM if you keep abreast of your settings, but I tend to use a scope most for debugging / fault finding, so I don't want to distract myself by thinking of the vert / horizontal settings. You really don't need an elaborate scope for audio work. The 20MHz Kenwood that I got decades ago probably does everything I need in truth. My scope can go for days without being switched on. That's in contrast to the FFT analyser, which goes on when I arrive at the workshop and stays on until I go home. I have some nice scopes, but for analogue duties, about 99% of their functions aren't needed.
I hardly ever use those, but each to their own. I agree with you on the scope use, though. I use my audio analyser more than I use the scope.
I do use the cursors on the digital scope, though. I would miss those on an analog scope, though the TEK2465 does have cursors. It's an odd digital/analog hybrid scope that way.
A scope can be needed for verification of some parameters. Slew rate for example. But for debugging I find that I use the DMM vastly more than the scope.
Tom
I picked up a 60 MHz LeCroy Digital scope at a local surplus purveyor for $150. It has 8 bits of accuracy, and came with probes. It also has a convenient USB port in front to dump image files into a memory stick. I still need to fire it up and get familiar with its user interface, though the manual may be there in the box with it.
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Agreed. I use the DVM's and audio analyzer most often. Those are big ticket items too. But I often grab the scope as well. Certainly once an amplifier is repaired to check for oscillation. Power supply noise and stuff like that. Main filter caps are best checked with the trusty scope, not a cap checker.
The Philips PM 3365A and PM 3070 all have cursors, as do the Agilent 54642D and Keysight MSOX3104T, and the Tek 2465B. But really accurate AC readings aren't normally needed, and if they are AC voltmeters can be more accurate anyway. HP 3400A anyone? LF AC amplitude measurements are okay with the HP/Keysight (and other modern True RMS meters with high frequency response). You can eyeball AC amplitude with an analogue scope, and they are not characterized as being exceptionally accurate anyway.
The Philips PM 3365A and PM 3070 all have cursors, as do the Agilent 54642D and Keysight MSOX3104T, and the Tek 2465B. But really accurate AC readings aren't normally needed, and if they are AC voltmeters can be more accurate anyway. HP 3400A anyone? LF AC amplitude measurements are okay with the HP/Keysight (and other modern True RMS meters with high frequency response). You can eyeball AC amplitude with an analogue scope, and they are not characterized as being exceptionally accurate anyway.
Not so fast- the 12-bit scope AC and DC measurements are as accurate as you'd need for any audio purpose I can think of. I have a couple 3400A meters and I think I've spent as much time repairing them as using them. The non-TRMS 400s are way more stable and reliable.
I'm just pointing out that an oscilloscope was never intended to be an accurate way to measure amplitude. Just as people read off every digit on a DVM, and that is total fantasy sometimes. The oscilloscope was intended to give you a good idea what the waveform looked like, rough amplitude and period. These things improved over the years like everything else. But just like a DVM, you can't just accept the number.
Try and see 1% THD on an oscilloscope. We don't use an oscilloscope for that.
Try and see 1% THD on an oscilloscope. We don't use an oscilloscope for that.