DC heater supply

[joesatch]

I have a regulated 12vdc heater supply, its rated at 2a. How many preamp tubes can i power with it? Merlin claims 300ma each or (600ma). Everyone claims they draw much less than this so i am confused.

[sluckey]

Bookmark this website and look it up.

     http://tdsl.duncanamps.com/tubesearch.php

A 12AX7 filament operating on 12V draws 150mA.

[joesatch]

would i need additional filtering if running 5 preamp tubes vs a pair?

[sluckey]

would i need additional filtering if running 5 preamp tubes vs a pair?

You have a regulated supply. Why would you need extra filtering? Won't hurt to add if it makes you feel good.

[kagliostro]

You must consider only to be within current abilities of the regoulator and to verify that the voltage you need is disposable


(when you rectify and stabilize the voltage the circuit will have a little drop out that for a 7812 is 2V, so, to have a correct 12V DC output you must respect the max current and have an input voltage of 12V at least more 2V (the drop voltage), obviously some (not much) volts more in input will result in better regoulation if input voltage has fluctuations)


Franco