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Paul S wrote:

Romy, doesn't Tim de P also use this cool Miller capacitance idea in his never-mentioned "high end" tubed corrector?  Also,  do I remember reading that he runs both channels through the two halves of the same twin-triode 9-pin tube?  Is this something you changed when adapting two units for stereo?  BTW, I have never heard the P88, or whatever he calls it.

Well, it was a long debate in the past if to keep my “End of Life Phonostage” as it use to be: six tubes, having 3 halves running right and left channels and keeping other halves half “cold”. I eventually decided to go for just 3 tubes running right and left on the opposite halves of the same twin-triode. I very careful considered the cons and pros and consulted with many people. I still do not know if my decision was “correct” but below is my rational. Subjectively I think that I did detect some very negligibly minor advantage of six tubes version but it was so none-conclusive and so non indicative that I discarded it as a margin of the experiment.

For using halves of the same twin-triode:

·  Less costly tubes.
·  Less inner chassis hit.
·  Less filament AC inside the phonostage chassis
·  More compact and elegant layout
·  Inability to reuse the tubes buy flipping them to another side when the current cathode is gone
·  The tubes of the right and left channels come from the “same barrel” (gas contamination, cathode poisoning etc)

Against using halves of the same twin-triode:

·   Alleged crosstalk

I truly do not know any other considerations then crosstalk and here how I thought:

According to the papers the crosstalk in the twin-triode is around 90dB-100dB. It is VERY high number; do not forget that cartridges have 20dB-30dB. The numbers of crosstalk are mystery for me and I was not able to see how extra 10-20dB of improved crosstalk do better for imaging subjectively. I figured that 90dB-100dB if electrical separation in twin-triode is too high do not worry about it. The 100dB of separation even my Macondo can’t handle as my horn pick the pressure from room and have their diaphragms to act as microphones. I have my amps off and might talk at my room in normal voice, having the channel loudness-to-pick- modulation meters on Macondo running a full scale…

So, I think and feel  that in practical application the theoretical crosstalk in twin-triode is way offset by the advantage I enumerated above.

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