AFAIK bias should be set to particular value. I asume you expect better performance setting bias higher. Increasing bias most likely won't improve the sound (otherwise everybody would do that) and is called overbias. Bias is usually set around 50-100mA and increasing it, while reducing slightly nonlinearities(that are reduced by negative feedback anyway), increases area of larger transconductance (gain) where two transistors work instead of one causing nonlinearities as well.
The problem is not with the bias but with negative feedback. Once gain before feedback was set high (like 4000) to make output linear then damage is already done and tweaking bias will not help much. Class A has gain before feedback as low as 200.
There are measurements of amplifiers' distortions with different bias setting that show clearly that increasing bias above some point will increase distortions.
The problem is not with the bias but with negative feedback. Once gain before feedback was set high (like 4000) to make output linear then damage is already done and tweaking bias will not help much. Class A has gain before feedback as low as 200.
There are measurements of amplifiers' distortions with different bias setting that show clearly that increasing bias above some point will increase distortions.