RIGOL DHO914S (and 924S) to learn audio work, buy connectors, use AWG, do builds

[Soulfistication]

Hi folks.  My first post - total newb, so please consider being kind, as I have already read  other material on this website, so my apologies if I missed some basic info already posted for this model on https://www.eevblog.com/forum/testgear/rigol-dho800900-topic-collection/msg5144856/#msg5144856 or elsewhere.

I recently purchased a Rigol DHO914S with the intent to learn about audio work and soundwaves, and develop some building and repair skills.  I am an active musician, but I do not have good electrical or technical skills (yet!).  My basic purpose is to become very familiar with a solid good long-term basic machine so I can observe soundwaves from my various instruments (guitar, synth, percussion, etc), do any necessary testing and troubleshooting for noise/errors/overtones/tuning, and also perhaps in the future do some basic building and repair of sound effects devices (e.g., guitar pedals, guitar tech work) plus maybe some more complex synth, stereo, speaker repair and building.  Primarily analog work, but perhaps if I become more adept then digital as well.   Gotta walk before I can run.  And actually I am in crawl mode . . .

So, in terms of first steps one of the initial things I want to do is simply connect devices correctly just to observe signals and start learning the machine.  I know there are some probes in the Rigol box, but what I really want to do is connect 1/4" and 1/8" mono audio outputs into the Rigol BNC inputs.  I am seeing a bunch of BNC adapters online, but am already getting confused about specs, and I don't want to waste money on a crappy adapter because it will be so core to the system.   So, could anyone please just kindly take a moment to recommend the best BNC adapter for mono audio inputs?  I presume I want one with male BNC, correct (the output on the Rigol hardware is female, right?).  And, I am hoping for a TS female cable - ideally really high quality with the correct impedance or other features for this particular Rigol machine (I am not clear on which electrical specs to match/consider when I look at the manual?).   I don't mind paying up for four good adapters that are solid, nor using a reputable dealer rather than some random amazon shot-in-the-dark.   All suggestions for parts or dealers are welcome.  I just know I want it in a high-quality low-noise durable cable (so there is flexibility and a bit of length such as 6 to 12 inches or so) rather than in a short stubby inflexible all-metal adapter.

Beyond that, are there perhaps other types of connectors I should consider?    RCA will likely be next on the list, seems easy enough.  Any others?  I see some "kits" out there, but not sure if many of the parts are irrelevant for audio testing and building, versus non-audio use where I just will not be interested.

Next, if I am just doing audio is there any need for me to hack the 914S up to 924S for bandwidth?  I see some posts on hacking, but I don't think this is needed for my use case, and I already paid up for the 914S to get AWG and avoid any odd issues.  No need for me to sweat doubling the bandwidth, correct?

Finally, is there perhaps a topic thread already about using the AWG in this particular model?   Apologies again if I missed this.   While I have plenty of synths to generate sound, I wanted the clean AWG signal, and I wanted it integrated with the scope, so I will be watching some videos to learn about the AWG features, and some good tricks - but I am happy for any recommendations on content, or links to specific AWG info for this particular model.

I hope those are fair questions, and perhaps if I have missed a thread on these particular topics someone can kindly just cross-reference it, and be patient with my very rudimentary inquiries here.

[themadhippy]

My method is bnc-phono socket ,and phono to whatever type of plug/ socket i need.

[ebastler]

Phono socket = RCA = Cinch, right? Then I fully agree, BNC <> phono socket are my standard adapters for consumer audio stuff too. Being very compact, they can be mounted right on the scope without creating a long lever which could damage the scope's BNC jacks. And they are cheap! 

Not sure if direct BNC <> 1/4" adapters exist, but I would be weary of using them since they would need to be quite long, creating strong leverage on the BNC jack. Better to use an adapter cable from the phono connector to whatever is needed next.

Oh, and regarding the 914 vs. 924 decision: I would certainly stick with the 914. The bandwidth is more than high enough for audio work -- you will probably find yourself activating the 20 MHz lowpass filter most of the time to further reduce noise, or activating enhanced resolution (14 bit or so). The benefit of the high bandwidth of the 924 model is a bit questionable even when you have faster signals, since the scope's sampling rate does not really keep up with the bandwidth, especially when using 3 or 4 channels: 300 MSa/s sampling rate is not enough to capture > 200 MHz bandwidth.

[themadhippy]

Phono socket = RCA = Cinch, right?

yep, t'is another of those different name for the same thing  us brits are good at

Better to use an adapter cable from the phono connector to whatever is needed next.

or use phono-phono rca-rca cables with this sorta thing on the end


they come in all sorts of flavors,even xlr

[shapirus]

or activating enhanced resolution (14 bit or so)

What are you referring to? Do the DHO900 scopes support anything like this? I couldn't find any mention of this in the manual (or elsewhere).

[ebastler]

or activating enhanced resolution (14 bit or so)

What are you referring to? Do the DHO900 scopes support anything like this? I couldn't find any mention of this in the manual (or elsewhere).

Ouch, you are right. The DHO1000 I had for a while supports this, but it is one of the few software differences between that series and its smaller siblings. I will strike it out in my post above, sorry for the confusion.

[Soulfistication]

Thanks for taking the time to reply - very helpful.     I had sort of discounted going BNC > RCA > 1/4 just to avoid an extra adapter and point of failure in the signal chain . . . but I see the point of keeping leverage/stress off the main hardware.

Are there any specs I need to keep in mind?   Any good manufacturers, or are they all pretty much the same in terms of quality?

Thanks also for the gut-check on 914 v 924 for audio.

I am hopeful someone provides more input on AWG use with this specific machine, but that will take me some time to learn . . .

Thanks again!

[donlisms]

Given the things you've said you'd like to do, I'm going to suggest you start with soldering and making your own cables.  You're going to need to soldering sooner or later anyway!

An easy way to get started, doing half the work yourself, is to buy BNC cables twice as long as you need, cut them in half, and put your choice of connectors on the cut ends.  You'll need to work out techniques for getting from the BNC coax down to, for example, the little 1/8" plug, and that sort of thing.  Doable in various ways.  Get some heat shrink tubing along with everything else.

I say that because, from my point of view, I'm not fond of adapters if I can avoid them, and I also find BNC connectors to be a pain to work with. So... best of both worlds.  And RCA is just nice to avoid also, when possible.

Buy connectors you like, without trying to find them already built into an adapter.

Add a couple of resistors to easily mix left and right channels into one signal. 

I don't think you mentioned any balanced signals, but you can also learn what's really going in with those, and how to interconnect balanced to unbalanced.  Rane's classic technical note is good, as is anything from... Bill Whitlock?  The Jensen transformer guy.  And others, of course.
--
As to your general pursuit, "understanding waveforms" is the key to understanding why it sounds the way it does, but there are a couple of ways to look at them.  The scope will give a nice direct picture, but I think the intuition comes when you compare it with an FFT of that signal, and can relate the harmonic structure to the shape of the wave.  It shows you "why," and gives you some definite things to play with as you search for perfection, or at least... understanding.

[Soulfistication]

wow, such great advice - thank you for taking the time to write that!!!  Yeah, funny you mention the soldering, I have just started dabbling a bit.   I do like your idea of cutting a BNC cable in half and customizing the ends . . . but I worry about my rudimentary skills causing me to end up with a bad test device.   I mean, I understand it is just a cable and connector and some solder, in theory anyway - but I have very low confidence right now in my skills, and so I might buy something stock until I get more practice and read those very helpful reference materials, then experiment further as you wisely suggest.  But I hear you . . . practice, practice!    Thanks.

Yes, FFT for sure - I did not mention in my original post but I am definitely looking to get familiar with that functionality.   I had noted the 914S had that feature . . .  does anyone happen to know if there is perhaps a prior legacy Rigol model with a similar/identical FFT application/protocol/feature list?  It would be useful to know so I can check into some legacy instructional videos.   It's probably me, but I don't find the 914S manual to be very intuitive or hands-on for a beginner - it's ok, and it is probably just me being clueless, but I am trying to ply through some youtube videos instead of just using the manual.

I suppose I have the same question about the AWG feature - not sure if there are legacy models with similar feature (and thus existing youtube content)?

I am an open book, but still on the first page or so . . . !

Thanks again!

[donlisms]

I'm glad my post seemed helpful. I do try to be!

Yes, practice.  I think any technical endeavor ends up better if you separate out the issues, work on learning one at a time.  Serious woodworking students practice making fine dovetail joints with hand tools.  The impulse is to just buy a fancy router jig, and start cutting in your finished pieces!  What could possibly go wrong?  :-)

I don't know about your specific devices.  I know the FFT on my Siglent is painful to use!  But sometimes necessary.  I learned a LOT more about waveforms and sounds and EQ with Digital Performer on my Mac. Clicky clicky, easy peasy; focus on the actual issues rather than trying to make the silly thing work right!