How to use multimeter


Could somebody guide me through a process?
I want to measure an output signal on my power amp to make sure it's equal in both channels ( I suspect it's not).
My idea is to play mono signal (pink noise?) and to measure voltage on amp's speaker terminals with speakers connected.
Please tell me a correct way to do it, I certainly don't want to damage my amp, and want to make sure I'm measuring what I suppose to measure.
If you think I know what settings on multimeter I should use- you are wrong, I don't.
That's what I mean: please guide me through.
maril555
1 Disconnect the speakers
2 Connect the multi-meter (MM) to channel 'A'.
3 Feed the amplfier a sine-wave (1000 Hz) through a pre-amp or pink-noise.
4 Set the MM on the AC Voltage setting. 1 - 150 volts range.
5 Turn up volume and take note of voltage on channel 'A'

Note - leave volume on this mark (ie. voltage will read 3.25 volts & use this to compare the other channels)

6 Mute amp or turn off and connect MM to next channel - 'B'
7 Repeat step 3 - 5 for ch 'B'
8 Advance through all channels and take voltage-level notes.

Make shure that you leave the volume control on the same setting when testing to get a correct reading. Always use the MM on the "V AC" setting. I would recommend using a shunt-resistor (8 ohm, 200 watts) in parallel with the MM.

You can also use a oscilloscope to check the channels... but alas, much more difficult.

Best of luck,
Dewald Visser

NB - Why don't you take the amp to a qualified technitian to get it checked. Accidents happen all to quickly!
Dewald,
Thanks for the detailed response, still I wanted to clarify a few points;
When you say: "Disconnect speaker and connect the MM to ch. A."- wouldn't it be a problem to have an amp running with no load on one channel and a load (speaker B) connectd to the other.
I guess you are saying it's impossible to measure an output voltage with the speaker connected.
Thanks again.
Hi there,

It is not impossible to measure voltage with a load connected - it only gives you a more accurate voltage measurement with no load or a shunt-load. Remember - as the frequency changes the IMPEDANCE of the speaker also changes.
Also remember to disconnect all other channels - both source cables and speaker-loads - all other channels (exept the one that you're measuring) must be 'mute'.
This is the defacto way to measure channels.

I would recommend connecting the shunt-resistor. Go to a radio-shack and let the technitian make on up for you. A 8 ohm, 100 watt resistor (with heatsink) with two short leads soldierd to it and the ends of the leads also soldierd. Use it in parallel with the Multi-Meter.

Sorry - My description might have been a bit skimpy.

Kind regards,
Dewald Visser