There are also Constant Voltage Transformers based on transformer saturation effect http://www.lenco-elect.com/constant_voltage.htm
The problem with them is poor efficiency and often some distortions of the sinewave.
Even if your voltage changes by 10%, your amp has, most likely some form of feedback making it regulated. Only max peaks will be affected and only if voltage drops. Lets assume drop of 10% making drop in available (peak) power of 20% it will change perceived loudness only by 5%. Just set your loudness not higher than 95% (to prevent clipping) and regulation will take care of the rest. Preamps, CDPs etc are all regulated.
Perceived loudness = k^(1/3.5) where k is ratio of powers.
Regulator will make it worse, in my opinion, since amplifier's supply current is in form of narrow spikes of high amplitude causing voltage drops - unless you use greatly oversized transformer or device that provides line AND load regulation.
The problem with them is poor efficiency and often some distortions of the sinewave.
Even if your voltage changes by 10%, your amp has, most likely some form of feedback making it regulated. Only max peaks will be affected and only if voltage drops. Lets assume drop of 10% making drop in available (peak) power of 20% it will change perceived loudness only by 5%. Just set your loudness not higher than 95% (to prevent clipping) and regulation will take care of the rest. Preamps, CDPs etc are all regulated.
Perceived loudness = k^(1/3.5) where k is ratio of powers.
Regulator will make it worse, in my opinion, since amplifier's supply current is in form of narrow spikes of high amplitude causing voltage drops - unless you use greatly oversized transformer or device that provides line AND load regulation.