Bias adjustment on solid state amplifiers


Why is there no mention of this in manuals, etc, with solid state amps? It seems with tube amps, there's a built in way to do it and/or mention of it in their manuals.
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Showing 1 response by minorl

There is no mention in most solid state owner's manuals for bias adjustment, because they are a design criteria and it is fixed.  The only time bias should need adjustment in solid state amps is when work was done on the amp and components were replaced. 

The bias, pre-driver and output drivers are typically located one the same heatsinks so that they may track with each other changes in heat.  hfe and other characteristics change with temperature.  This is why they are mounted on the same heat sinks.

Typical owners have no business adjusting bias on solid state amps.  

Also, many companies won't even tell you what the bias voltages (typically across emitter resistors) are in the first place.  Try getting that information from Mark Levinson company.  

If you upgrade the transistors to much better more linear transistors from older transistors, then yes, you need to know what the bias voltage should be.  If you add say, Threshold style heat sinks and want your class a/b amp to operate more in class A, then yes, you need to adjust bias.  upgrading the power supply and transistors are typically also required in this case.

enjoy