Oscilloscope Probe to Audio Line In? USB Scopes?

[outoftune]

Hi,

Wondering if anyone has any experience with using / modifying an oscilloscope probe so it can feed a line input of a soundcard (RME Babyface).

I'm using Spectrafoo for analysis and am trying to see if I can replace my trusty Tektronix analog scope with the probe feeding the sound card.

The purpose of this would be for occasional signal probing to troubleshoot, doesn't need to be insanely accurate but just needs to be able to display a signal for circuit tracing. Any input would be much appreciated!

 

[moamps]

The line input of a soundcard has usually min. 10 times lower impedance (resistive and capacitive component) than the scope input so you will get lot of measuring errors if you like to measure high impedance circuits. Also, some Tek probes have fixed internal attenuation (1:10 or 1:100) so IMO you can't use them for your purpose. But, you can use your probe if it is 1:1 and your measurement will be limited to audio spectrum. 

 

[outoftune]

The line input of a soundcard has usually min. 10 times lower impedance (resistive and capacitive component) than the scope input so you will get lot of measuring errors if you like to measure high impedance circuits. Also, some Tek probes have fixed internal attenuation (1:10 or 1:100) so IMO you can't use them for your purpose. But, you can use your probe if it is 1:1 and your measurement will be limited to audio spectrum. 

thanks for the info. do you know if it would be possible to use something like a DI transformer (~10:1) to correct the mismatch or would more circuitry be require?

 

[PRR]

Why not the shell of a BIC pen and some stiff wire?

If you are poking more than 2V, put in a 100K:1K resistor divider.

 

[moamps]

...... do you know if it would be possible to use something like a DI transformer .....

DI transformer isn't good solution. Google "active probe" for a simple  impedance converter.