I have a Rigol 1054z scope.
Would this Hameg HZ109 be ok?
Hameg HZ109
A alternative is buying two 50ohm termination BNCs and use CH1 + CH2 as a diff.
What i want is a way to measure power supply ripple/noise.
Any advice here?
Would this Hameg HZ109 be ok?
Hameg HZ109
A alternative is buying two 50ohm termination BNCs and use CH1 + CH2 as a diff.
What i want is a way to measure power supply ripple/noise.
Any advice here?
Not sure why you need differential probes to measure power supply ripple. A good 1M/10M probe with sufficient voltage rating for the supply you are testing is all that should be required.
Differential voltage and high side current measurements require differential probes or a pair of well matched probes with a scope supporting differential measurements across two input channels.
What are you attempting to do that requires a differential probe?
Differential voltage and high side current measurements require differential probes or a pair of well matched probes with a scope supporting differential measurements across two input channels.
What are you attempting to do that requires a differential probe?
Look at this measurement i did today:
https://postimg.cc/image/o6obzex45/
You can se a lot of high freq noise even with the 20M bandwidth limit.
If you look closely there is spikes parallel to the 10ms grid.
This is the speaker output from a Denon poa 2200 amp with no input connected.
I would want to know if this is coming from the amps power supply or if its just some spikes coming from somewhere else.
Maybe I'm just overthinking it.
Does all the noise go away after turning the amp off?
How about with the amplifier's input shorted?
I dont know and i cant test it now because i don't have the amp here :/
My friends new Canton speakers, both of them have dead tweeters.
This is after replacing 8 10000uF 80V filter caps, but i dont think it has anything to do with it.
There is 5mV dc at both left and right output with no input connected and no speakers connected.
Just looking for anything obvious here.
10ms div thats about 100Hz? Wouldn't that be heard trough the speakers if it was coming from the amp?
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Check to make sure what you are seeing is not an aliasing product, by choosing faster sweep speeds and try to figure out what you are actually looking at.
Tweeter failure (burned out VC) may have several causes:
5mV of dc offset is pretty low as solid state amps go, anything over 50mV (my opinion) would concern me, although historically100mV was often considered acceptable even with 4 ohm drivers.
Tweeter failure (burned out VC) may have several causes:
- Inaudible HF oscillation
- Long term clipping due to a heavy hand on the volume control
- Cross-over component failure
5mV of dc offset is pretty low as solid state amps go, anything over 50mV (my opinion) would concern me, although historically100mV was often considered acceptable even with 4 ohm drivers.
I don't have the unit here unfortunately so i cant do any more measurements.
While putting some music into the input and scoping the output showed only music dancing on the display.
Told my friend the amp is probably ok and he will test it trough some cheaper speakers.
But I learned some new stuff today measuring the output of an amp of my own.
There was a huge decrease in noise picked up when i disconnected the short ground lead from the probe.
Instead used the very short spring tip attached. Could not imagine the difference it made!
Maybe i don't need a diff probe after all.
While putting some music into the input and scoping the output showed only music dancing on the display.
Told my friend the amp is probably ok and he will test it trough some cheaper speakers.
But I learned some new stuff today measuring the output of an amp of my own.
There was a huge decrease in noise picked up when i disconnected the short ground lead from the probe.
Instead used the very short spring tip attached. Could not imagine the difference it made!
Maybe i don't need a diff probe after all.
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That's all typical of a wide band scope. Also make sure you don't have a ground loop with the scope ground and amp ground through the mains.
An open input on an amp will pickup noise from everywhere to some degree. it will get much worse if you touch the center terminal. The valid way to check an amp for noise is with all inputs shorted. Nothing will come out of the amp above a Megahertz or it won't pass EMI testing. 20 MHz is still wide enough to get some misleading noise just from wires in the box and radiated noise from all manner of stuff. The longer ground clip creates a larger loop to pick up noise even if its shorted to the tip. You can some times use that a a probe to find out what is radiating.
You don't need a differential probe unless you are looking for something very specific. The diff probe from QuantAsylum is the best value out there (by far) but only if you use it. It also includes a current pickup. QA190 Differential Probe
An open input on an amp will pickup noise from everywhere to some degree. it will get much worse if you touch the center terminal. The valid way to check an amp for noise is with all inputs shorted. Nothing will come out of the amp above a Megahertz or it won't pass EMI testing. 20 MHz is still wide enough to get some misleading noise just from wires in the box and radiated noise from all manner of stuff. The longer ground clip creates a larger loop to pick up noise even if its shorted to the tip. You can some times use that a a probe to find out what is radiating.
You don't need a differential probe unless you are looking for something very specific. The diff probe from QuantAsylum is the best value out there (by far) but only if you use it. It also includes a current pickup. QA190 Differential Probe
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