I have made it back into DIY audio after about 30 years. In the mode of buying tools. Have most of what I need but am wanting an Oscilloscope. I have plans to build speaker and electronics...no RF though.
Does anyone have any recommnedations at to capability...range, storing, channels, etc.?
Thanks
Does anyone have any recommnedations at to capability...range, storing, channels, etc.?
Thanks
Stand alone or USB based?
My recommendation is 2 channels minimum and 20MHz will cover audio and also find oscillation issues in discrete amps.
For working class D you might consider a higher bandwidth.
USB scopes can be cheap (as low as $100) and may fit your need.
One other option is to build an adapter board and use a sound card input with some of the audio software that has been mentioned in other threads. This has some advantages of gain and thd testing.
Things to think about.
My recommendation is 2 channels minimum and 20MHz will cover audio and also find oscillation issues in discrete amps.
For working class D you might consider a higher bandwidth.
USB scopes can be cheap (as low as $100) and may fit your need.
One other option is to build an adapter board and use a sound card input with some of the audio software that has been mentioned in other threads. This has some advantages of gain and thd testing.
Things to think about.
I'd go for a good analogue scope, I wouldn't hesitate. The resolution on complex waveforms is "infinite" within its bandwidth, the digital scope (unless you pay megabucks) doesn't come close.
Two shots of what should be identical waveforms, post #24 here
http://www.diyaudio.com/forums/digital-source/225504-primare-laser-change-2.html#post3290406
It seemed as though the digital scope couldn't resolve what is a complex waveform.
And this is from my analogue scope
Two shots of what should be identical waveforms, post #24 here
http://www.diyaudio.com/forums/digital-source/225504-primare-laser-change-2.html#post3290406
It seemed as though the digital scope couldn't resolve what is a complex waveform.
And this is from my analogue scope
If you don't mind looking at used 'scopes, the analogue Hitachis are good - I have a somewhat older V1065 that has a nice crisp CRT and triggers reliably (Mooly - nice pic of CDP RF eye pattern, a good test!), and Iwatsu made many reasonable analogue 'scopes that are often found in cleanouts of defunct TV repair businesses, the CRTs are a bit variable when they get old however - try before you buy unless dirt cheap.
Tenma... dare I say cheap and cheerful. I have a Tenma function generator which while excellent for the price had an annoying and extremely hard to find intermitent fault which I eventually traced to a dodgy crimped lead in a multiway plug.
I agree with radiotron, a used scope would be far better. I used to use an Hitachi for work day in day out... it was excellent...a along with an older Trio.
My own is a Hung Chang 5510, 100Mhz, the 100Mhz version of this,
Hung Chang 5506 Oscilloscope 60 MHz 3 Channel | eBay
I have a few pieces of TENMA gear. DMMs and temparture meters. Not sure where the name comes from. I think it is the the electronics equivolent for Harbor Freight...which is fine. You just have to be aware of what it is.
I see the brand Tektronix quite a bit. Wondering if it is as good as the price it demands. I have nothing against buying used but I haven't had much luck in that area, so I buy new when I can. Just my experience.
I see the brand Tektronix quite a bit. Wondering if it is as good as the price it demands. I have nothing against buying used but I haven't had much luck in that area, so I buy new when I can. Just my experience.
I'm in exactly the same boat. Last time I was into diy electronics I'd built my own Heathkit oscilloscope from a billion individual parts and it was never worth a darn, not very stable, not very good focus, no storage, no automatic measurements. I've been shopping ever since. I have bids on eBay right now, and I often get outbid on what I really want, so I'm not going to say too much more to my competitors until I buy.
I want something better than PC sound card software. A USB adapter might suffice but I'd want more real knobs than they usually provide. The handhelds don't have much of a display, so I'd usually use them as a USB adapter type anyway, but with a few more controls. I hate up/down buttons for sensitivity and time, I can swing a knob back & forth once and then go directly where I want it, but usually buttons suck. The ones that look like an old analog but are only a few inches deep seem nice. I like the huge storage memory of the digital scopes so I can replay to measure, and I really like the big display capabilities of the really good digital scopes connected to a PC. A 200mhz digital scope with fast sampling looks just fine to me, and its always in focus, but the good stuff is expensive. Two scopes, one good digital and one good amalog, might seem ideal, but I think if you put that kind of total money into one good digital it might make the analog redundant.
There's other considerations using 'scopes for working on tube circuits. I have a gift for blowing out "indestructable" test equipment. A second set of more appropriate high-voltage very-high-impedance probes. Maybe a third set for looking at the motorcycle's ignition output? Completely isolated true differential inputs where neither has any reference to ground is a really handy feature when you want to record two traces of only a few volts AC each, including showing a DC component, but which are 500+ volts away from each other or ground. Some scopes feature inputs that are optically isolated; they sure don't achieve 200+mhz by blinking an incandescent bulb for the opto-isolator so I assume they must use some kind of LED or lazer? At various times I've done despicable things like floating my entire 'scope and breadboard off any ground via isolation transformers, then found myself afraid to touch a plastic knobs for fear of a deadly 500-volt jolt off the faceplate or from a setscrew in the knob finding my body an attractive ground. My dad used to have long probes with insulators that looked like they should be hanging from a power pole.
I want something better than PC sound card software. A USB adapter might suffice but I'd want more real knobs than they usually provide. The handhelds don't have much of a display, so I'd usually use them as a USB adapter type anyway, but with a few more controls. I hate up/down buttons for sensitivity and time, I can swing a knob back & forth once and then go directly where I want it, but usually buttons suck. The ones that look like an old analog but are only a few inches deep seem nice. I like the huge storage memory of the digital scopes so I can replay to measure, and I really like the big display capabilities of the really good digital scopes connected to a PC. A 200mhz digital scope with fast sampling looks just fine to me, and its always in focus, but the good stuff is expensive. Two scopes, one good digital and one good amalog, might seem ideal, but I think if you put that kind of total money into one good digital it might make the analog redundant.
There's other considerations using 'scopes for working on tube circuits. I have a gift for blowing out "indestructable" test equipment. A second set of more appropriate high-voltage very-high-impedance probes. Maybe a third set for looking at the motorcycle's ignition output? Completely isolated true differential inputs where neither has any reference to ground is a really handy feature when you want to record two traces of only a few volts AC each, including showing a DC component, but which are 500+ volts away from each other or ground. Some scopes feature inputs that are optically isolated; they sure don't achieve 200+mhz by blinking an incandescent bulb for the opto-isolator so I assume they must use some kind of LED or lazer? At various times I've done despicable things like floating my entire 'scope and breadboard off any ground via isolation transformers, then found myself afraid to touch a plastic knobs for fear of a deadly 500-volt jolt off the faceplate or from a setscrew in the knob finding my body an attractive ground. My dad used to have long probes with insulators that looked like they should be hanging from a power pole.
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Well, somebody out-bid me. Good thing I guess, I really should pay down bills first. I've got two VTVMs to refurbish first anyway.
If you search around, you can find the favorite classic analog Tektronics scopes of the guys who repair & refurb them. Too early and the Tektronix are enormous, tube, less stable, need frequent calibration, and parts can be difficult to get. The more recent use a lot of application-specific integrated circuits which are only obtainable now by salvage out of other scopes. Just like there's a 'classic' tube amp era that's easy to work on yet uses reasonably modern components, apparently the same is true of oscilloscopes unless you want a disposable 'scope. There are classic models which are wonderfully stable, yet easy to work on. Then you just get a used one with a good bright well-focused picture on the tube.
If you search around, you can find the favorite classic analog Tektronics scopes of the guys who repair & refurb them. Too early and the Tektronix are enormous, tube, less stable, need frequent calibration, and parts can be difficult to get. The more recent use a lot of application-specific integrated circuits which are only obtainable now by salvage out of other scopes. Just like there's a 'classic' tube amp era that's easy to work on yet uses reasonably modern components, apparently the same is true of oscilloscopes unless you want a disposable 'scope. There are classic models which are wonderfully stable, yet easy to work on. Then you just get a used one with a good bright well-focused picture on the tube.
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this looks at least to be a decent deal. any thoughts?
Tenma 100MHz Dual Channel Digital Storage Oscilloscope | 72-8385 (728385) | Tenma
Tenma 100MHz Dual Channel Digital Storage Oscilloscope | 72-8385 (728385) | Tenma
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