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Old 8th May 2011, 02:39 PM   #1
Merlot is offline Merlot  Canada
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Default Oscilloscope Question

I want to apologize in advance. I see lots of threads dealing with this topic, which are very helpful, but none specifically answer my question.

I am looking at purchasing an oscilloscope. Specifically I am looking at the Rigol DS1052E. It costs about $400 (not too expensive) and seems to get good reviews. I've never used one before but have always wanted one. I want to learn more about them and use it in servicing my tube amps ( Bob Latino ST-70 and ST-120s). I also intend building a preamp. I know I could get a used oscilloscope cheaper but as my wife says I have more money than brains.


The specs are here:

DS1052E::RIGOL

I am not sure how to read the specs and my question is this: The voltages in the amps are around say 500v. The input on the scope has a limit of 300v. There is a 10x attenuation switch on the probe. Can I use this oscilloscope to measure voltages etc. in the amps? Anything else I should think about? Is this a reasonable scope for the intended purpose?

Appreciate your thoughts.
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Old 8th May 2011, 06:19 PM   #2
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It looks like 300v is an overload rating, like it will withstand 300v buts its not a good idea. My old HP scope has a 40 volt measurement limit so combine that with a 10:1 probe and you can do up to 400.

It looks like a decent beginners scope. The 8 bit resolution is low if you plan to do any serious FFT readings but you can get a PC sound card for that.
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Old 8th May 2011, 07:20 PM   #3
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You can use a 50x or 100x probe.

paul
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Old 8th May 2011, 08:21 PM   #4
cbdb is offline cbdb  Canada
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Quote:
You can use a 50x or 100x probe.
Or DIY and build a voltage divider with a couple of resistors.
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Old 9th May 2011, 02:22 AM   #5
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Normally 10:1 probes will be used, so look for a probe rating of 500V or more.
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Old 11th May 2011, 06:08 AM   #6
chrish is offline chrish  Australia
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I have that scope. If you are interested, there are software hacks available to turn it in to a 100Hz scope (50 and 100 Hz scopes are identical internally, it just requires a software switch by reloading the firmware). As mentioned, the 8 bit resolution is somewhat limiting. I use it to make measurements and to store wave forms etc. If you can stretch it, purchase an old analog scope as well (or at a later date) as it will have better screen resolution for determining oscillation, and for seeing a truer representation of the waveform (distortion etc).

I have an old Tek 2225 that I had first, thinking I would replace it with the Rigol. Rather than replace, I think they compliment each other well for the reasons listed above.
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Old 11th May 2011, 08:08 AM   #7
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To learn more about o'scopes Tektronix has a good and free pdf XYZs of Oscilloscopes.
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Old 17th May 2011, 03:28 PM   #8
Merlot is offline Merlot  Canada
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Chirsh,

Thanks for the input. I've been reading up on digital scopes and note the limits of 8 bit resolution. I'm now thinking of an analog scope, specifically this Tenma (MCM Electronics):

Tenma 20MHz Oscilloscope with Function Generator | 72-6805 (726805) | Tenma

Any thoughts on this one? Recall I want to be measuring tube amp voltages.

I see in the specs it can measure up to 300V. The amps have in the region of 500V. Presumably the 10x probe would reduce that to say 50V making it acceptable to the scope?

Appreciate any thoughts...
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Old 17th May 2011, 04:54 PM   #9
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Quote:
Originally Posted by sofaspud View Post
To learn more about o'scopes Tektronix has a good and free pdf XYZs of Oscilloscopes.

Tektronix X100 probes cost a pocket.
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Old 17th May 2011, 05:13 PM   #10
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the specs say the sensitivity is 5mv to 5 volts per division. There are 8 squares or divisions on the screen, with a 10x probe the max you will be able to see is 400 volts. So you will not be able to measure DC voltages higher than 400 VDC with a probe but that doesn't mean you cannot measure the AC ripple on the high DC voltage lines. You will have to check what is the maximum voltage the probes can handle AC + DC. There is a probe on that web site that has a max of 600 volts AC + DC. So that should work for you. Bear in mind that at 605 volts the probe wont probably fail but will be good till 700 or 800 volts.
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