My latest 300B amplifier brought me again closer to the D3a. I have to say it’s an exceptional driver for this amp as well as it can perform in a phono stage at same excellent level.
I took the opportunity to trace again one Siemens D3a NOS boxed as “POS 1.176 Q 31-X 601”. This one was handpicked as it measured at 102% (31mA) in triode mode with a Gm of 39mS.
I wanted to develop a pentode model for phono experiments so put this lovely valve back in the eTracer and used the Extract Model tool from Derk Reefman to develop the model below.