SE EL84 build - which PT?

[theRagman]

I've got a single-ended EL84 amp design in front of me that I'm going to build. It pulls about 46mA of current. I have two power transformers handy that will supply the voltage I want. As for current, one of the transformers just squeaks over the design point at 50 mA, and the other is massive overkill at 115 mA. Which would you recommend using? Is "just squeaking over the requirement" good enough, or would it make sense to build in a buffer?

[shooter]

do you like the smell of burning electronics 30 minutes into a killer set, on stage, in front of all your fans 
IF YES;


keep the other as a spare, pick up a spare 84 just in case
otherwise;


is this experimenting or going for a daily noodl'n amp?
If experimenting you might find like I have, just 1 SE tube just misses the mark, but parallel a 2nd one, bam, we found some magic.
you'll need that extra current, somewhere down this lonely road of xSE.....

[theRagman]

do you like the smell of burning electronics 30 minutes into a killer set, on stage, in front of all your fans 
IF YES;


keep the other as a spare, pick up a spare 84 just in case
otherwise;


is this experimenting or going for a daily noodl'n amp?
If experimenting you might find like I have, just 1 SE tube just misses the mark, but parallel a 2nd one, bam, we found some magic.
you'll need that extra current, somewhere down this lonely road of xSE.....

Experimenting. It's all experimenting at this point--I'm not competent enough to build something I'd trust onstage. :)

And I am definitely not a fan of the smell of burning electronics!

[Merlin]

Transformers are pretty forgiving, I would think the 50mA model is fine. You can always tweak the bias current down to 40mA or something

[kagliostro]

I would like only to remember that if you have ... say 100mA AC current available a rule of thumb say you'll have 60mA DC available, also remember that in a PP amp the load swing from idle to max and in an SE amp it will stay all the time around the max

So, remember to verify if the available current is AC or DC, it isn't the same thing

Franco

[theRagman]

Transformers are pretty forgiving, I would think the 50mA model is fine. You can always tweak the bias current down to 40mA or something

Thanks for this. My general temptation on all things engineering is to overbuild everything, but that comes with consequences that need to be managed. Knowing that transformers are pretty forgiving is super helpful.