Question about Oscilloscope needs

[jfjohn77]

OK, first off I'm new to this electronics testing hobby. I'm just wanting to diagnose and repair my stereo integrated amp. I've never owned an oscilloscope, but I want to get one. I'm just trying to determine what is necessary and what is overkill for my needs. Specifically bit rate and deep memory. Is 12 bit necessary, or just nice to have? And, what about memory, what should the minimum be? I'm really not interested in an old analog scope... to make sure I'm getting one that is working and remains that way, it would probably cost me as much as a Digital scope. I respect and appreciate any suggestions from those with both more knowledge and experience than myself.

[ebastler]

While you did not give us much information about your requirements and budget, I'll bite...

If it's really just to repair one stereo amp, do not buy an oscilloscope at all. Find a makerspace in the area and take your amp there. You will get access to the required equipment and, ideally, someone who can help you learn the ropes. If you enjoy the repair and really want to make this a regular hobby, get back to the "what to buy" question.

(Do you have the other paraphernalia needed for basic electronics work? Multimeter(s), soldering iron, hot air station (for SMD rework), maybe a signal generator and lab power supply? This is a rabbit hole, and I would not enter it prompted by a single project.)

12 bit resolution is very useful for audio work, where you may want to see low-level noise superimposed on a larger signal. It is less relevant for digital work. Conversely, the lowest available sample rates are sufficient for audio work -- but modern amplifiers are not entirely analog; they will have digital sections that require higher sampling rates. Four channels are really useful for digital work, but can be helpful for audio too, letting you compare and correlate signals at multiple points in the circuit.

If and when you decide that getting your own scope makes sense, I would go for a Siglent SDS804X HD or a Rigol DHO 804. In contrast to the bottom-of-the-barrel brands, these manufacturers support their products with firmware updates -- both scopes have improved quite a bit since their launch. Rigol is widely considered the easier-to-use product, while Siglent has somewhat better signal processing and analysis capabilities.

[Grandchuck]

ebastler gave you good advice!

Maybe you could ask around and borrow a scope?  Seems iffy to buy a scope for one repair project.  Ham radio operators are usually friendly and eager to help even with non-radio interests.

If you do go ahead, please be sure to learn about the safety issues involved with connecting scopes to line operated devices!!!

[Sorama]

Let’s not forget the most important thing:knowledge.

[coromonadalix]

+1  for Eblaster comments

your requirements need to be more defined,  and you dont have any absolute machine or test equipment,   audio is one thing, data, more complex signal, protocol decoding  etc ... are others

some analog  if found cheap could be very good

Rigol and Siglent are popular because of the free possible bandwith upgrades,  search threads here there are many   ... get some models and do searchs here


many members will express their point of views,  not necessarly yours ...

[Peabody]

Most who post here are EEs.  If you are not an engineer, it's possible your needs will be different from those of a professional.

One option is to buy an inexpensive hand-held battery-powered scope from the Far East, possibly just a single-channel one.  You can get a scope like that for about US$50.  The brand that seems to be reviewed most favorably is Zeeweii.  Their Aliexpress store is here:

https://www.aliexpress.com/store/1101600990

I have such a scope that is far less capable than models available today, and I still use it frequently.  Since it's not referenced to Earth ground, it's hard to destroy, and even if that happened, you haven't lost much.

Of course it depends on where you're headed with this in the future.  But something cheap that's fully capable of dealing with anything related to audio frequencies might give you all you need for now, and would let you learn about how to work with scopes.  It might even be all you'll ever need.

[nctnico]

Ebastler brings up a good point: ease of use. One of the pitfalls is to get lured into having (too) many features which in the end turn out to be hard to drive and/or barely useable due to lack of speed.

There are many more brands out there next to Rigol and Siglent. Like GW Instek which makes scopes which are easy to operate. Or Miscig with their tablet form factor scope. And there is also the used market. One of the bare bones scopes I like is the Tektronix TBS2000 series. Easy to use, nice crisp traces and no fuss. Nowadays these can be bought for reasonable prices on the 2nd hand market. The best way forward is to create a list with contenders, list pros & cons, determine your own use cases and watch reviews to see how a piece of equipment operates. If you can, try to get some hands on experience with some models before purchasing. Maybe there is a school or makerspace where you can try for yourself.

[KungFuJosh]

The above is generally good advice. However, if you want an oscilloscope to own and learn with in addition to your single project, then you should state a budget you're comfortable with. Inexpensive means different things to different people.

Thanks,
Josh

[studiot]

Yes ebastler gave great advice.

One more thing,

If you detail the amp make and model and its symptoms and what you are connecting to as it may not be the amp at fault, you can expect lots of help here.

[tautech]

OK, first off I'm new to this electronics testing hobby. I'm just wanting to diagnose and repair my stereo integrated amp. I've never owned an oscilloscope, but I want to get one. I'm just trying to determine what is necessary and what is overkill for my needs. Specifically bit rate and deep memory. Is 12 bit necessary, or just nice to have? And, what about memory, what should the minimum be? I'm really not interested in an old analog scope... to make sure I'm getting one that is working and remains that way, it would probably cost me as much as a Digital scope. I respect and appreciate any suggestions from those with both more knowledge and experience than myself.

SDS802X HD is what instantly came to mind for your needs and it seems from your own research that's what you're pursuing. 

Nice little scope with plenty of capability to grow into.
Coupled with any of Siglent's AWG's its Bode plot feature is very useful for checking/tuning filters.....probably something to consider adding down the road a bit.

Have a study here for what you can accomplish with a SDS800X HD:
https://www.eevblog.com/forum/testgear/sds800x-hd-review-demonstration-thread/

[bson]

You can also get a Zoytek ZT-703; it doubles as a basic handheld DMM and a very basic oscilloscope.  But it's enough to check for signs of life; if you feed your amplifier 1kHz in for example (which the ZT will generate) and there's nothing out on a channel, then you can use it to follow the signal down a schematic to see where in the amplifier it vanishes.

[Doctorandus_P]

People have "made do" with 8 bit digital scopes for 30+ years. I very nearly bought an SDS210 back then but when I went to the shop to buy it (I had not been there for a few months) it was suddenly 20% more expensive.

When I'm repairing things, one of the first things to do is to check supply voltages, and I usually do that with a scope, because a DMM does not show ripple (or barely on a secondary display). You can do on-screen voltage measurement with a scope but with an 8-bitter it's quite limited. A 12-bitter would give you an extra digit which is quite nice for all measurement functions.

Scopes have an accuracy of a few percent, so keep that in mind when doing measurements, but you do get too see smaller changes. for example, when measuring overshoot, then with an 8-bit scope you just have a few bits to measure the overshoot with an 8 bitter.

For general scope usage (observing the waveform), more bits does not improve the experience much because the resolution of the screen itself is the limit. You'd have to zoom in to see the difference.

[watchmaker]

The problem with buying a scope is that it wants playmates like a sig gen, dmm, etc.  The $400 is just a down payment.

Dewey

[ebastler]

While the OP has not followed up here at all, I see that he has asked for a discount code for the SDS802X HD in another thread. I still think he is jumping the gun there, but if he want a scope right now, it's not a bad choice. Anyway, I guess we can consider this thread resolved, at least as far as the OP is concerned.