What do you guys like about them OR what do they give you over/in comparison to the stock tubes?
I find the RCA 2A3 gray plates have more "midrange magic" and a slightly more holographic presentation.
They do have some more hum compared to the stock EH2A3, but have low 'tube rush' noise like the stock tube.
What is an acceptable difference in "ma" for a so called "matched pair" of DHT's for the LIO??
I'm not so sure you can use that spec to determine how well a pair is matched in the LIO DHT PRE circuit. I do it
by measuring the L/R outputs of the DHT stage with my scope to confirm how well matched they are in this design.
I'm happy when they are matched to within 0.5dB or better.
(And the LIO NUDE RVC volume control is already very tightly matched via the Z-foil resistors, which I believe have a tolerance
of 0.5% or lower). And LIO has a balance control if you find you need to use it (approx. 1dB steps to the L or R).