LA2a power transformer

[Moses Dmj]

Hey guys,

How much current do your LA2a clones draw from the power transformer (not counting heater current, of course)? I want to cram two of them in one box with one power transformer/PSU and make a stereo unit... David J's book says the original had a 500V CT / 40mA max, so I was thinking at least 80mA to power two... but Hammond apparently doesn't make their 270CBX no more (100mA); they only go up to 70mA on 250-0-250V transformers...

Will a 70mA transformer be enough to power two units? what are you guys using in your clones?

Thanks,

 

[beatnik]

If I'm safe assuming you live in a 230V mains voltage country you should look at the Hammond 300 series instead. the 200 series is 115V primary only

370DAX should have enough plate and filament current for two La-2a channels.

 

[dmp]

I don't know the current draw off the top of my head, but you can download the schematic and see it has DC voltages noted. All you need is ohm's law to calculate the current to every branch and then sum them. B+ starts at 275v and goes 6 ways to the tubes through resistors. I get about 27 mA total. But try it yourself.
And then definitely consider some kind of safety factor, 40mA per channels seems reasonable.