Yes you can. In fact many people do it all of the time, military, State Department, contractors, and a slew of government agencies. The most predominant method of using US 120 volt equipment in Europe is with transformers. A transformer merely converts the line voltage, not the Herz, so your clock radio and some devices that rely on 60 Herz will not work. I know companies that have put in 120 volt transformers at the mains coming from major power lines for housing and hospitals. You can use a regular in the house transformer. There are many. You could ask for someone to hardwire a transformer into the house main power and run lines to the rooms where you need the 120 power, again, no 60 Herz. Using a transformer does not cost but a few cents when plugged in and no device is sucking the power from it. When you do use a transformer an important rule of thumb to remember is to have at least twice as much wattage available for the device as the power rating that you are using, depending on the device of course, so that you do not smoke the transformer.
If you truly want your equipment, you will bring it and use transformers, many have before you. Just remember, a turntable with a motor that relies on 60 Herz, will not operate at 50 Herz properly. Also, some equipment that use switches and relays based on oscillating frequencies, will probably not work correctly either. Any solid state or tube pre-amp or amp should work fine. Check the specifics of the receiver. Also, your computer is probably dual voltage, as power for computers is converted to 5 volt DC from the power supply, which should be switchable from outside, or may need to be opened up. I have never seen a desktop computer system with only a 120 volt power supply. They are pretty much universal. Monitors are also auto switching nowadays. I am also starting to see a trend in subwoofers becoming dual voltage. Don't forget the need for 220 volt to 120 plug adapters. Your transformer, depending on type, may have up to 4 120 outlets, you can plug your 120 items in directly without plug adapters. I have used various transformer ratings from 100 watt to a 3000 watt at various times of my life stationed overseas with great success. Oh, make sure the line current from the house can support a surge of 2,000 watts or more in the case of big transformers. Whatever the rating of the transformer is; is the amount of watts that will initially surge through the transformer when you turn it on. It is a onetime shot, much like turning on a high power amp. Most breakers are 16amps x 220 volts in Germany, equating to about 3520 watts available on the circuit where the transformer is plugged in. Any electronic that is plugged into that same circuit will eat at the available watts and can cause a circuit breaker to go off when you power up a monster transformer.
I have spent many years overseas, to include building a house, to pretty much having experienced most of these types of issues.
Audioquest4life
If you truly want your equipment, you will bring it and use transformers, many have before you. Just remember, a turntable with a motor that relies on 60 Herz, will not operate at 50 Herz properly. Also, some equipment that use switches and relays based on oscillating frequencies, will probably not work correctly either. Any solid state or tube pre-amp or amp should work fine. Check the specifics of the receiver. Also, your computer is probably dual voltage, as power for computers is converted to 5 volt DC from the power supply, which should be switchable from outside, or may need to be opened up. I have never seen a desktop computer system with only a 120 volt power supply. They are pretty much universal. Monitors are also auto switching nowadays. I am also starting to see a trend in subwoofers becoming dual voltage. Don't forget the need for 220 volt to 120 plug adapters. Your transformer, depending on type, may have up to 4 120 outlets, you can plug your 120 items in directly without plug adapters. I have used various transformer ratings from 100 watt to a 3000 watt at various times of my life stationed overseas with great success. Oh, make sure the line current from the house can support a surge of 2,000 watts or more in the case of big transformers. Whatever the rating of the transformer is; is the amount of watts that will initially surge through the transformer when you turn it on. It is a onetime shot, much like turning on a high power amp. Most breakers are 16amps x 220 volts in Germany, equating to about 3520 watts available on the circuit where the transformer is plugged in. Any electronic that is plugged into that same circuit will eat at the available watts and can cause a circuit breaker to go off when you power up a monster transformer.
I have spent many years overseas, to include building a house, to pretty much having experienced most of these types of issues.
Audioquest4life