Just tried this step up transformer bought from TechnoFix on eBay, TL019-R 1438.
Sounded amazing connected to the Pleiades V4 pre preamplifier.
The coupling capacitor to grid on V4 is 220nF. It is very important to capacitor couple to an electron tube grid so that the valve's grid is free. (Not made by force to assume a potential).
The primary inductance of the transformer is 100mH at 1028Hz and 165mH at 97Hz making wonders at compensating the proximity effect of the MD421HL and SM58 (made in Mexico) used. Mic mouth distance approximately 1 in.
Connecting the transformer to the grid of the EF183 made the high frequency response high but not high enough to sound over detailed and unnatural. It seems therefore to compensate the high frequency proximity effect due to the obstacle effect too.
Secondary inductance is 7H making a 1:8.5 step up.
Bravo to the designers, a giant killer!
Sounded amazing connected to the Pleiades V4 pre preamplifier.
The coupling capacitor to grid on V4 is 220nF. It is very important to capacitor couple to an electron tube grid so that the valve's grid is free. (Not made by force to assume a potential).
The primary inductance of the transformer is 100mH at 1028Hz and 165mH at 97Hz making wonders at compensating the proximity effect of the MD421HL and SM58 (made in Mexico) used. Mic mouth distance approximately 1 in.
Connecting the transformer to the grid of the EF183 made the high frequency response high but not high enough to sound over detailed and unnatural. It seems therefore to compensate the high frequency proximity effect due to the obstacle effect too.
Secondary inductance is 7H making a 1:8.5 step up.
Bravo to the designers, a giant killer!
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