After tweaking my test rig to fit a variable supply for fixed bias, I proceeded with the tests with the EML20AM valve. 
Tag: EML20AM
EML 20-AM DHT curves and model
There is one DHT which attracted me from Emission Labs which is the EML20. If you’re looking for a mid-mu DHT valve these days, this one is the way to go. In order to meet with the two key requirements of linearity and low microphonic noise, EML made a great effort in producing this valve.
For me it’s a great candidate as a driver or for a Spud amp for headphones. I will likely use them in several places, but will start with a preamp stage, as you would expect from me anyway.