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Reduced 6922 Current (6.5 mA) results are good!

Posted by jyourison (A) on March 30, 2015 at 21:05:11

In Reply to: RE: Effects of Source to Ground adjustment posted by Eli Duttman on March 30, 2015 at 17:15:10:

The results are positive. No flat top at 2Vrms input with slightly less current through the 6922. The splitter legs are symmetrical, too. See the first image below. This is 1KHz at 2Vrms,10V per division. The resistances are equal for each leg.

NOTE: With both sides equal in resistance, the waveforms for top and bottom legs looked good.

One glitch was a Source to Ground leg measurement, which showed some oscillation. I have had this before, and it may be a probe issue, although it does show up on both channels at times, and with both of my probes. It sometimes disappears. It could be the lanky breadboard layout too. Any tips for checking into that would be helpful. One positive note is that it disappears at 1.86Vrms. So it would only appear at full volume with the volume pot turned all the way up.

See the next image and the "bubble" of possible oscillation. Anyone know what this represents and why it might be occasional?

Here is the same wave form from Source to Ground, with the input slightly reduced by 0.14V, or at 1.86V. (The blurred curve is my fault, not the trace):

Over all I am more than happy with the shape this is taking.

--Jeff

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