Dear,
The impedance of 500 Ohm is the result of the 4 layer Platinum coil. A two layer has an impedance of around 250 Ohm (just half of the 4 layer impedance). But the output is also 50% of the 4 layer output. To have enough output, minimal 0,35 mV at 5,6 cm/sec, a 2 layer coils creates a problem ()based on the higher coil impedance combined with the lower output). It might be hard to understand, so I am very open for a better solution.
With a primary load of minimal 500 Ohm and a secondary of 50 KOhm, the ratio must be 1 : 10. With the.WE618B, the ratio is 1 : 6,45 what is not enough even where there will be sonic output. Your sound quality is not what you can expect from your Colibri XPW or XPP.
With Best Regards,
A.J. van den Hul.
用升压牛的话,范老头推荐使用500:50K,10倍变比。