A MXLV67 is a solid state microphone. Older V69s are tube to a transformerless output circuit microphones. I have a number of both.
http://www.mxlmics.com/products/Studio_mics/all_studio.html I do see a v67i tube
I don't like the simple Schoeps like circuit Dorsey mod. One can rework the stock v67/2001 circuit better than the Dorsey. You do need to know what to do. For one thing it does not have capsule EQ and the article is missing important thing like transistor specs.
X50 better?
MXLV69 (older transformerless) uses a tube as an anode charge amp follower. I traced a cathode biased gain stage 200VDC B+ with a 50pf plate to grid capsule is about 50pf so overall gain should end up at -1. That stage feed a partly epoxy? covered board for the transformerless out. So except for noise and microphonics not much sound change when you change the tube.
http://www.mxlmics.com/products/Studio_mics/all_studio.html I do see a v67i tube
I don't like the simple Schoeps like circuit Dorsey mod. One can rework the stock v67/2001 circuit better than the Dorsey. You do need to know what to do. For one thing it does not have capsule EQ and the article is missing important thing like transistor specs.
X50 better?
MXLV69 (older transformerless) uses a tube as an anode charge amp follower. I traced a cathode biased gain stage 200VDC B+ with a 50pf plate to grid capsule is about 50pf so overall gain should end up at -1. That stage feed a partly epoxy? covered board for the transformerless out. So except for noise and microphonics not much sound change when you change the tube.