Re: EL84 and E84L
I haven't heard of the E-84L's, but I know that with E-34L's, they're 10% higher output than EL-34's. And they're interchangeable, but you've got to bias it a little hotter.
On my Biasing the Jubilee thread, you'll notice I settled on 40mA, rather than 38mA, and the reason is that those tubes are E-34L's.