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I have to admit that although the Macondo “Water Drop Tweeter” sounds very good but I do not have that “shocking sound” that I got from the “Water Drop” during my initial introduction to it. I kind of always felt it and I thought that I get use to it but now I think differently. What is the problem is that in my current version of Milq my HF channel suffers from the same problem of low-passing die to the high grid impedance as I described above.

After all, the grid has the same 500pF of the 6E5P and 32.1K impedance… I can not test the “Water Drop” with other channel as it is direct to plate bound and I was thinking about the two stages and inner stage filtration. I hate to lose the super cleanness of a single stage for HF… and then it came to me: the 6E5P is a TETRODE. The Weekeipida says:

“The second grid, called "screen grid" or sometimes "shield grid", provides a screening effect, isolating the control grid from the anode. This helps to suppress unwanted oscillation, and to reduce an undesirable effect in triodes called the "Miller effect", where the gain of the tube causes a feedback effect which increases the apparent capacitance of the tube's grid, limiting the tube's high-frequency gain. In normal operation the screen grid is connected to a positive voltage, and bypassed to the cathode with a capacitor. This shields the grid from the anode, reducing Miller capacitance between those two electrodes to a very low level and improving the tube's gain at high frequencies. When the tetrode was introduced, a typical triode had a input capacitance of about 5 pF, but the screen grid reduced this capacitance to about 0.01 pF.”

Well, why do not flip my single 6E5P into tetrode?   The datasheet on 6E5P said that in tetrode mode it has 0.006pF. The gain will be higher. Let say 200, so it will be still under the whopping 1pF that will give me response over 100kHz. To do so I need juts to flip one wire on my 6E5P and to listen the result. If it works then it will be so elegant solution for tweeter!!!

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