Krell KSA300S Power Conversion

If power transformer of your Krell have additional power leads, than using variac, you can ID these by measuring an output voltages to be same as with 110V. In other words, all you have to do is record measurements between lead and chassis, compare and swap one with corresponding other. If you don't have variac(a-must for most of electronic work indeed) than simply, figure out each output of secondary winding of transformer leads for 220V conversion will have approximately half the voltage as ones originally in the circuit. Most companies usually mark down the voltage values on PCB, but if that's not the case, you should measure each output voltage with disconnected lead(unsoldered if necessary)

If power transformer has only one set of leads, than you will need to replace it with 220V version which is less likely the case. 

Also, if you find service manual, or able to convince dealer or manufacturer to provide you one, than you'll be in great shape knowing color code of each corresponding lead to make it much faster. Lately I found most of manufacturers believe you're dumb and not savvy to fix equipment therefore would not share with you any information about any DIY on their stuff. It brings them more money selling new units. You may also search service manuals on vinylengine.com, but this site mostly have vintage units that used to provide them together with unit in good old 60's,70's, 80's. Most of these manuals would simply state "if you're not sure to troubleshoot yourself, bring it to qualified tech". 

Good luck with your endeavor. 

" Krell will probably want a few hundred dollars to do this but IMO it's money well spent".
Hey don't forget about +another $hundred shipping turnaround. In some cases international shipping can apply as well.
" In any case, if you do not have a service manual or a schematic of the power supply you will be flying blind"
It's all about tracing power transformer to clear visibility. Not every time schematic needed.