It's not simple. You need to have load-sharing resistors that degrade the regulation. Check page 22 of the LM117 datasheet. They show an implementation where they add an opamp and a reference to improve regulation. In fact the regulators are used like power transistors, with the advantage that they have bulit-in SOA and thermal protection.kambo said:can i parallel connect LM350s or any other voltage regulators in parallel ?
thanks
kambo
You can use multiple regulators. An LM317 can deliver about 1.5A, suitable for 5 12AX7's.kambo said:thank you so much for the info.
checked page 20 and all, OMG, that is a lot of work...
i guess i just switch to 6.3VAC heater supply.
kambo said:i will be using 2x6SN7 and 2x5687 at 6.3 vdc. = 3 amp... (slowblow micpre)
i will go with 6.3VAC 6amp transformer option...
Just make sure you use the GTB version of 6SN7, that has controlled heater time.kambo said:thinking again, if i connect heaters serial on two 6SN7 for 12v(6.3+6.3=12.6), and 5687's individually serial for 12v, then, i am at 1.5amp
Marginally more expensive, not really a problem for one-offs; only reason I was reluctant is I don't like the TO3 package, but I see that it is also available in TO220.kambo said:how about LM338 5amp
mjrippe said:Personally, I can't think of a single piece of *vintage* tube audio gear with regulated filaments. DC filaments, sure, but not regulated.
kambo said:mjrippe said:Personally, I can't think of a single piece of *vintage* tube audio gear with regulated filaments. DC filaments, sure, but not regulated.
so, diode bridge, with some caps and a huge power resistor to adjust 6.3vdc ?
kambo said:hey Kingston,
" A few big caps with a big-watt dropper resistor "
any example to this ?
( not even single diode, just caps and resistor ? )
LT3080 is definitely not right for the application. Thermal resistance is likely to be about 60-65°C/W. That would put a limit of about 1W per chip.Kingston said:There are some regulators that are specifically designed with paralleling in mind. Great example is the LT3080, but it's far too high end for your heater needs, competing with super regulators quite equally. Go with abbeys suggestion.
buildafriend said:Btw, while we're on it I'm interested a DC heater circuit with paralleled 3080's.
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