power supply help

[smitty]

Hello,

quick question on pwr supply...  and how a stompbox uses available current.   Im planning on building a valvecaster, which uses
a 12au7 tube, and have an 18.5 volt powersupply rated at 2.7 amps....     the valvecaster runs a maximum of 150ma for the heater,
and a max of 11.8ma of current for the plates (which is if running plates at 100v, I will be running at 18 volts on the plates and 12 volts for the heater)...
So my question is:   Does the 18 volt power supply have 2.7amps of available current for the pedal to use, and the pedal just "takes"
what it needs in terms of current.   Or does the power supply feed the pedal 2.7 amps of current and blow up my tube .....   Do you think I could
use this power supply, or would it be wise to find a power supply with a current flow more in line with my power requirements?

thanks very much for the help,

smitty

[Govmnt_Lacky]

All that means is that your power supply will provide AT LEAST 18.5V of power UP TO 2.7 amps of current draw.

You pedal SHOULD NOT draw anywhere near 2.7A of current unless something is terribly wrong 

More than likely, your supply is putting out MORE than 18.5V when it is not under full load. Be sure to measure it first to see if your regulator will handle it.

Good Luck 

[smitty]

All that means is that your power supply will provide AT LEAST 18.5V of power UP TO 2.7 amps of current draw.

You pedal SHOULD NOT draw anywhere near 2.7A of current unless something is terribly wrong 

More than likely, your supply is putting out MORE than 18.5V when it is not under full load. Be sure to measure it first to see if your regulator will handle it.

Good Luck 

Thanks for the response....   this is a regulated power supply...  when I measure the voltage it is at 18.5 on the spot.... I think it is a compaq laptop power supply...   looks like i need to reverse the polarity of the barrel connector as well, looks like it should work...   

thanks again,

smitty