Most amps have a power consumption rating. Class A amps will draw a steady current until forced to A/B. Class A/B amps fluctuate draw on demand. Some, like a Carver Lightstar (300 wpc) can draw up to 15 amps at peak, however unlikely. As a guideline:
50 wpc stereo = 300 VA (watts) input, roughly 3 amps,
100 wpc = 500 VA, roughly 5 amps
As a general rule a transformer should be double the VA of the demand but 2 KVA would be the minimum I would suggest, even for a small amp. Honest three KVA, but not all, would allow 15 amps of most household outlets and weigh about 75 lbs. Wired for balanced AC, derate by half. No transformer will convert Hz but that shouldn't be a probelem for pre/amps. It could be a problem for a CDP or DAC but most of those can be either 50/60 Hz.
I use a 120 lb,5 KVA tranny for 20 amp balanced.
50 wpc stereo = 300 VA (watts) input, roughly 3 amps,
100 wpc = 500 VA, roughly 5 amps
As a general rule a transformer should be double the VA of the demand but 2 KVA would be the minimum I would suggest, even for a small amp. Honest three KVA, but not all, would allow 15 amps of most household outlets and weigh about 75 lbs. Wired for balanced AC, derate by half. No transformer will convert Hz but that shouldn't be a probelem for pre/amps. It could be a problem for a CDP or DAC but most of those can be either 50/60 Hz.
I use a 120 lb,5 KVA tranny for 20 amp balanced.