Hi,
I am looking for an oscilloscope possibly used.
For now purpose is for making/verifying power supplies for ripple /noises etc from DAC supplies to tube pre amps.
I never used one before so this will be my first one.
There is also plan to use it on tube gear with peak voltage of 400V inside.
What should be specifications I should be looking for?
Is it still recommendation to use analog over digital entry level scopes?
I am looking for an oscilloscope possibly used.
For now purpose is for making/verifying power supplies for ripple /noises etc from DAC supplies to tube pre amps.
I never used one before so this will be my first one.
There is also plan to use it on tube gear with peak voltage of 400V inside.
What should be specifications I should be looking for?
Is it still recommendation to use analog over digital entry level scopes?
Hi. this is a bit of a fun video, but the guy knows his stuff, hope it helps https://www.youtube.com/watch?v=Xh9FNRpta9s&t=417s
I was in a similar position to you not long ago and bought a secondhand Gould OS 300. It's 20MHz and can handle 400V dc/ ac p-p.
Probably something with similar specs would suit you for starters
Probably something with similar specs would suit you for starters
I'll stir the pot.
ANY 'scope beats peering into the output jack wondering what's-up.
I had good service from a 100KHz (0.1MHz) 'scope. Audio experts say you want 20MHz to see parasitic oscillations. My experience is if you have a 20MHz 'scope, your circuit sings 40MHz. Mostly you "know" you have parasitics when the DC-20KHz waveforms are not right, and can be made worse-better by adding capacitance (even a pencil-tip) around certain points of the circuit.
I've done work with a very low-gain 'scope, 0.1V would not fill the screen. If I need to see very small stuff, a 19-cent opamp will boost fine. Most recent 'scopes have plenty of gain, it is almost the cheapest feature they can add.
While CRT 'scopes are the gold standard, I had excellent service from the first pop-price flat-panel, a Velleman with just 64 display steps. Sure everything was jaggy, but still very informative. They do not make displays that crude anymore. I don't think that Vellie was even 100KHz, but it was never an issue for me.
Sound-card 'scopes have got quite clever. But I don't like hooking a PC to experimental rigs, and obviously a soundcard's ADC does not have the excess resolution wanted to test your own ADC/DAC path.
I did a LOT of work with single-channel 'scopes. When I got a 2-Ch job, it opened some new ways to look but did not revolutionize my life or make me rich. Take 2-Ch if otherwise a good deal, but don't hold-out for it. (Compared to the rest of the 'scope, another channel is small cost, so recent 'scopes are mostly 2-ch... 1-Ch may be a super-cheap model with other shortcomings.)
> use it on tube gear with peak voltage of 400V inside.
The usual 'scope input can take a few Volts. The universal way to extend this is with a 10X divider probe. With a tiny cap to compensate it to the 20MHz limit. I got TOO good at blowing-up these probe caps. (Also a few VTVM inputs.) (Also testing auto ignition primaries.) The old ones used 500V caps, but today 100V is likely. Recall that if you get on the output transformer, a 400V supply is 700+V peaks! _I_ would build a dedicated tube-amp "probe". 1Meg and 1K make 1000:1 divider (makes math simple, mV=V). The low output impedance makes stray C moot. A good 1Meg 1W resistor will take 350V for years and won't blow-up with over 1,000V on it for a test. (Or string three 330K.) Dubious over 50KHz but most audio plate-work is below that.
So I'll say: don't sweat the specs. They are likely more than you need now.
> possibly used
The 'scope is typically the MOST sophisticated equipment on a bench, for obvious reason (it has to be better than the stuff it measures). Don't buy a fixer-upper if you don't have other test gear and extensive experience. The $99 China LCD-scopes beat heck out of a fine old Tektronix which "needs work" you can't manage.
ANY 'scope beats peering into the output jack wondering what's-up.
I had good service from a 100KHz (0.1MHz) 'scope. Audio experts say you want 20MHz to see parasitic oscillations. My experience is if you have a 20MHz 'scope, your circuit sings 40MHz. Mostly you "know" you have parasitics when the DC-20KHz waveforms are not right, and can be made worse-better by adding capacitance (even a pencil-tip) around certain points of the circuit.
I've done work with a very low-gain 'scope, 0.1V would not fill the screen. If I need to see very small stuff, a 19-cent opamp will boost fine. Most recent 'scopes have plenty of gain, it is almost the cheapest feature they can add.
While CRT 'scopes are the gold standard, I had excellent service from the first pop-price flat-panel, a Velleman with just 64 display steps. Sure everything was jaggy, but still very informative. They do not make displays that crude anymore. I don't think that Vellie was even 100KHz, but it was never an issue for me.
Sound-card 'scopes have got quite clever. But I don't like hooking a PC to experimental rigs, and obviously a soundcard's ADC does not have the excess resolution wanted to test your own ADC/DAC path.
I did a LOT of work with single-channel 'scopes. When I got a 2-Ch job, it opened some new ways to look but did not revolutionize my life or make me rich. Take 2-Ch if otherwise a good deal, but don't hold-out for it. (Compared to the rest of the 'scope, another channel is small cost, so recent 'scopes are mostly 2-ch... 1-Ch may be a super-cheap model with other shortcomings.)
> use it on tube gear with peak voltage of 400V inside.
The usual 'scope input can take a few Volts. The universal way to extend this is with a 10X divider probe. With a tiny cap to compensate it to the 20MHz limit. I got TOO good at blowing-up these probe caps. (Also a few VTVM inputs.) (Also testing auto ignition primaries.) The old ones used 500V caps, but today 100V is likely. Recall that if you get on the output transformer, a 400V supply is 700+V peaks! _I_ would build a dedicated tube-amp "probe". 1Meg and 1K make 1000:1 divider (makes math simple, mV=V). The low output impedance makes stray C moot. A good 1Meg 1W resistor will take 350V for years and won't blow-up with over 1,000V on it for a test. (Or string three 330K.) Dubious over 50KHz but most audio plate-work is below that.
So I'll say: don't sweat the specs. They are likely more than you need now.
> possibly used
The 'scope is typically the MOST sophisticated equipment on a bench, for obvious reason (it has to be better than the stuff it measures). Don't buy a fixer-upper if you don't have other test gear and extensive experience. The $99 China LCD-scopes beat heck out of a fine old Tektronix which "needs work" you can't manage.
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if you can find a Hitachi V-665 cheap and in good shape, you won't be sorry.
here's a good picture: http://www.eevblog.com/forum/beginn...-beginner/?action=dlattach;attach=27173;image
mlloyd1
here's a good picture: http://www.eevblog.com/forum/beginn...-beginner/?action=dlattach;attach=27173;image
mlloyd1
Thank you. I read somewhere the minimum AC voltage resolution of 2mV/DIV is needed and to measure AC ripple you need DC coupled option available in oscilloscope.Is this standard in all Oscilloscopes that it won't be mentioned or should I be looking for it?
Also, can oscilloscopes be used for jitter measurement from audio DAC?
What type of probes are needed as part of standard equipment and for digital audio use?
Also, can oscilloscopes be used for jitter measurement from audio DAC?
What type of probes are needed as part of standard equipment and for digital audio use?
If you have no experience then you have a real learning curve ahead in interpreting the displayed waveforms.
if you want specs I find 500 KHz and 1mV to 5 mV more than enough for most tasks. As above you can always make use of more but I usually have the bandwidth filters on to lower the noise.
I would get an older Tek to start with. Something like a T922 or a 5000 but I know what I'm looking for. The big problem with older scopes is that they are big and expensive to ship. However they define wysiwyg, no aliasing or other odd stuff to confuse you. The Tektronix scopes always had the best triggering in the analog scope era.
I have used both Rigol and Tek DSO's and pre-learning curve the Tek was just faster to use and less likely to give a misleading display. With time and experience any would be OK. The Rigol's are a great value for the price. My big issue with digital scopes is that you really need to know what you are looking for before you probe to know if what you see is correct. For troubleshooting this can be a problem.
If you expect to probe in tube amps you should get stuff designed to work safely at those voltages. The inexpensive probes may be rated for the voltages but having the extra distance and large clip of an older Tek probe makes it safer and easier. They fit tube lugs much better since they are from the tube era. Something like a P6006 which are available at reasonable prices on eBay.
I would check your local Craigslist for something you can pick up and check out. Any scope that is working would probably be a good starting point. What ever you get will either do the job or teach you what you need.
if you want specs I find 500 KHz and 1mV to 5 mV more than enough for most tasks. As above you can always make use of more but I usually have the bandwidth filters on to lower the noise.
I would get an older Tek to start with. Something like a T922 or a 5000 but I know what I'm looking for. The big problem with older scopes is that they are big and expensive to ship. However they define wysiwyg, no aliasing or other odd stuff to confuse you. The Tektronix scopes always had the best triggering in the analog scope era.
I have used both Rigol and Tek DSO's and pre-learning curve the Tek was just faster to use and less likely to give a misleading display. With time and experience any would be OK. The Rigol's are a great value for the price. My big issue with digital scopes is that you really need to know what you are looking for before you probe to know if what you see is correct. For troubleshooting this can be a problem.
If you expect to probe in tube amps you should get stuff designed to work safely at those voltages. The inexpensive probes may be rated for the voltages but having the extra distance and large clip of an older Tek probe makes it safer and easier. They fit tube lugs much better since they are from the tube era. Something like a P6006 which are available at reasonable prices on eBay.
I would check your local Craigslist for something you can pick up and check out. Any scope that is working would probably be a good starting point. What ever you get will either do the job or teach you what you need.
1) pretty much any scope will have ac coupling. Your issue will be max voltage. For 400V in a tube amp + a 10X probe you need 40V of input cap so that won't be a big issue.
2) The only scopes that ccome anywhere near looking at jitter on a clock are $40K digital signal analyzers that are hard to use and fragile. You can use a good soundcard for measuring jitter with a J-Test test track. Fixing/improving jitter will be difficult.
3) for the digital side you need a fast 10X probe and a fast scope. The master clocks can be as high as 96-100 MHz and usually are 24 MHz range. The analog side will not have much above 100 KHz except for filter leakage up to about 4 MHz usually. A scope will show you that things are working or not. A scope won't show distortion, jitter etc. unless its incredibly bad.
Scopes
We have many good used Kenwood CS 4025 dual 20MHz scopes for sale
$100 + freight.
Call Zed Audio at 805 499 5559 PST
We have many good used Kenwood CS 4025 dual 20MHz scopes for sale
$100 + freight.
Call Zed Audio at 805 499 5559 PST
> I read somewhere the minimum AC voltage resolution of 2mV/DIV is needed
You can read anything "somewhere".
Why 2mV?
And what reasonable 'scopes don't get near 2mV? (My 100mV/full scale 'scope was a classroom special, and works out as 12mV/div (if it had divs) so a 2mV squiggle could be seen, if not clearly measured.)
> to measure AC ripple you need DC coupled option
No, you need _AC_ coupled, which all 'scopes have; and even then it is risky. I learned to put a 0.1u cap to a 1Meg resistor to ground, with two diode clamps, and let it settle before poking the 'scope at it. While a good 'scope with a savvy repair department can take a lot of abuse, it is often wiser to plan your tests so no great strain is placed on the 'scope.
You can read anything "somewhere".
Why 2mV?
And what reasonable 'scopes don't get near 2mV? (My 100mV/full scale 'scope was a classroom special, and works out as 12mV/div (if it had divs) so a 2mV squiggle could be seen, if not clearly measured.)
> to measure AC ripple you need DC coupled option
No, you need _AC_ coupled, which all 'scopes have; and even then it is risky. I learned to put a 0.1u cap to a 1Meg resistor to ground, with two diode clamps, and let it settle before poking the 'scope at it. While a good 'scope with a savvy repair department can take a lot of abuse, it is often wiser to plan your tests so no great strain is placed on the 'scope.
recently purchased this one:
https://www.circuitspecialists.com/siglent-sds1202x-200mhz-2ch-14m-memory-oscilloscope.html
Happy with it.
But as Demian mentioned, your really need to understand what you are seeing. This oscilloscope shows up a lot of things in the circuit some of which are not pretty 🙂
https://www.circuitspecialists.com/siglent-sds1202x-200mhz-2ch-14m-memory-oscilloscope.html
Happy with it.
But as Demian mentioned, your really need to understand what you are seeing. This oscilloscope shows up a lot of things in the circuit some of which are not pretty 🙂
I am sort of in the same boat and would was thinking of this scope. "Rigol DS1054Z"
What do you guy's think of his one.
What do you guy's think of his one.
More than you ever wanted to know: New Rigol DS1054Z oscilloscope - Page 1 Its actually quite decent but you can see there are lots of details people are fiddling with.
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