Having this distortion in the 1943 5200 80W amplifiers will it harm my transistor? I am getting a better response with this distortion I do not know why. This distortion starts at about 1khz and goes up to 20khz. I know how to get rid of this distortion but it changes the response of the system which doesn't match my speakers.
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It seems a kind of zero crossing distortion, frequency dependent. So, it may be that any bias (mainly in the output pair) is being shifted with frequency. I think in a small capacitance (0.1uF) across the Vbe multiplier or rectification in any stage in DC coupled circuits or a capacitor or resistor degraded by ageing or thermal stress.
Osvaldo is probably right to check the assembly of the VBE multiplier, there is surely an anomaly to have such a signal at the output.
Yes. Not 100% sure, but easy to try. Keep an eye in the bias adj preset. If yoy see it degraded, replace it. A fault in it can produce a disaster in the output stage.
The amount of crossover distortion is frequency dependent because the amount of feedback available to reduce it is falling with frequency. 100% normal in the usual amplifier topologies. You can push where this up-tick occurs above 20KHz with careful design, but you’ll never get rid of the rise. The bias is just set too low. Whether is a faulty preset pot, a resistor that shifted, or other is still TBD, so leave no stone unturned.
