O'scope Back to Basics for you guys... a learning game...

[dorrisant]

Please show us how set up the scope to check filter caps for excessive ripple and hum... counting frequencies and such.

Tony

[John_P_WI]

Hi

oscillation above the rated bandwidth might well produce a "fuzzy trace" on a good analogue scope.

John

Yes, fuzzies, thickening of the waveform, or spikes riding along.

Tony, my mule amp is on the bench stripped to its' chassis. As I build it up I will be sure to scope it out along the way and post here - the hardest thing is to decide what I want to build this time.

[martin manning]

This is an old post, but it's some more fun and games with an o-scope: https://tubeamparchive.com/viewtopic.ph ... highlight=

[dorrisant]

This is an old post, but it's some more fun and games with an o-scope: https://tubeamparchive.com/index.php

Is that some kind of sick joke? Lol.

Tony

[martin manning]

No, some kind of a mental lapse. New link edited in above.

[John_P_WI]

Thanks Martin, any more?

Anyone else?

[dorrisant]

Here is a nice little document... Don says "If you post then anywhere please mention that the doc was put together quickly for the purpose of help one individual person and more than likely contains errors and omissions. I never went back through it for a sanity check."

http://www.soultrampamps.com/wp-content ... _scope.pdf

[Structo]

Thanks Tony

[Aurora]

There is one thing that I've pointed out before, - as ppl mention checking ripple on filter caps.... make sure you don't exceed the scope amplifier input. The max input is usually printed next to the input connector.
Max scope input is often in the 50V range,- plus or minus... with a x10 probe, that makes a max of 500V, often exceeded by high power amps.. Some Music Mans come to mind. You may need a x100 probe for such stuff.

[xtian]

You can safely measure ripple by putting a 600v 0.1uF cap in series with the probe, right?

[dorrisant]

Whatv he said ^^^... This is the one thing that I would like to se demonstrated.... How to check the filters for correct performance. Maybe some screen shots...?

[Aurora]

A .1uF cap is 166 kohms at 60 Hz, which must be concidered as a resistance in series with the probes input resitance - if scope input is 10Mohms - it will present a slightly erroneous measurement, but max voltage very mauch still the same....

[schaublin65]

Hi,

read your scope manual carefully.

My little Tek 323 manual specifies max 500VDC + AC

"with or without probe"

As Aurora has pointed out, a 10:1 probe may not be safe.

How close you want to get to a nominal 600V limit on chinese Ebay rated probes might be worth thinking about too......

Take lots of care. Some mistakes don't give you a second chance...

John

[martin manning]

Happened upon this tutorial, which includes some links:
https://learn.sparkfun.com/tutorials/ho ... 1426494604