How do I check the output of an amp with a scope?
in [Repair]
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From: fynnashba on 30 Jun 2010 14:38 Hello' I have built a mic amp and wanted to check the wave form on a scope but when I connect the probes to the o/p of the amp the power supply trips (The Mic operates on 9 volt single rail.) I connected the scopes ground probe to the -ve (common) and the output to the other probe. the scope works alright with a signal generator. The Mic also works on a power Amp but with some noise. What might be the problem?
From: whit3rd on 30 Jun 2010 16:15 On Jun 30, 11:38 am, "fynnas...(a)yahoo.com" <fynnas...(a)yahoo.com> wrote: > I have built a mic amp and wanted to check the wave form on a > scope but when I connect the probes to the o/p of the amp the power > supply trips (The Mic operates on 9 volt single rail.) Is one of your scope probes a GROUND connection? Couple to the microphone amp output through a coupling transformer, see if that helps. Which power supply trips, the scope, or the microphone amp? What are the specifications of that power supply?
From: fynnashba on 30 Jun 2010 16:38 On Jun 30, 8:15 pm, whit3rd <whit...(a)gmail.com> wrote: > On Jun 30, 11:38 am, "fynnas...(a)yahoo.com" <fynnas...(a)yahoo.com> > wrote: > > > I have built a mic amp and wanted to check the wave form on a > > scope but when I connect the probes to the o/p of the amp the power > > supply trips (The Mic operates on 9 volt single rail.) > > Is one of your scope probes a GROUND connection? Couple to the > microphone amp output through a coupling transformer, see if that > helps. > > Which power supply trips, the scope, or the microphone amp? What > are the specifications of that power supply? Thanks no the ground connection of the scope is connected directly to the Amp Its the power supply connected to the amp that trips or reads about 4 volts instead of 9v The current of the PSU was set to 1 Ampere. Please, generally, how do you check the responds of an audio Amp on the scope? I mean how the probes are connected.
From: tm on 30 Jun 2010 18:39 <fynnashba(a)yahoo.com> wrote in message news:3f09618b-db62-4f12-a3de-f130b2b6920b(a)u26g2000yqu.googlegroups.com... On Jun 30, 8:15 pm, whit3rd <whit...(a)gmail.com> wrote: > On Jun 30, 11:38 am, "fynnas...(a)yahoo.com" <fynnas...(a)yahoo.com> > wrote: > > > I have built a mic amp and wanted to check the wave form on a > > scope but when I connect the probes to the o/p of the amp the power > > supply trips (The Mic operates on 9 volt single rail.) > > Is one of your scope probes a GROUND connection? Couple to the > microphone amp output through a coupling transformer, see if that > helps. > > Which power supply trips, the scope, or the microphone amp? What > are the specifications of that power supply? ..Thanks .. no the ground connection of the scope is connected directly to the ..Amp ..Its the power supply connected to the amp that trips or reads about 4 ..volts instead of 9v ..The current of the PSU was set to 1 Ampere. ..Please, generally, how do you check the responds of an audio Amp on ..the scope? I mean how the probes are connected. Do you have a two channel scope? Can you invert and add one of the channels? If so, make a differential connection to the output with the scope ground connected to the chassis ground of the amp. Put the inverted probe on the low side of the output and the non-inverted probe on the high side. The vertical gain for both channels must be the same and in the calibrated mode. --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: William Sommerwerck on 30 Jun 2010 19:47
I suspect the original poster doesn't know much about electronics. We should stop trying to help him, and ask that he find someone "local" (in his own country) who can explain how to use test equipment. |