Hello, I think the differences you've mentioned shouldn't have a significant impact on the overall performance or sound of the amp, especially if all other voltages are within the expected range.
geometry dash liteIn addition, As for the tone control, I think it's not unusual to experience a slight volume boost when engaging it. Depending on the circuit design and components used, tone controls can sometimes introduce a small increase in volume. This can happen due to the interaction between the tone control circuitry and the overall gain structure of the amplifier. However, the volume boost should be subtle and not overpowering.