Crrs is the important parameter for the Mosfet.......low capacitance for the others is likewise important, Ciss, Coss.....the lower these figures, the better.....
higher Ciss means you will have to operate the driver tube at higher plate current for good high frequency response....
higher Ciss means you will have to operate the driver tube at higher plate current for good high frequency response....
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Just an Update...
i had put a voltage divider. just a series 440k resistor after the coupling cap..the divider formed by 440k and the grid leak resitor of 330k...is it okay with this or i put the divider before coupling cap?
I've lowered the 6n6p cathode bias to 4v and increased the ccs current to around 12ma..i came close to 1/2 b+ at output and improved the sound...bass is hard and tight but a little weak on highs...I use 2sk1341 Mosfet (900v.6A, 100w) with a ciss of 980, Coss of 400 and Crss of 165. Is it good for this design? the ccs mosfet K560 has a higher wattage and capacitances but i think ,it cannot affect since it is only a CCS...
I've also tried using 6N1P's on parallel as Tony suggest but sound is dull..so i reverted it back to 6n6p..... on the next sitting ...i will try to use a pentode and tetrodes,,triode connected in place of 6n6p and see if the sound will be more improved...
BTW, what will be expected gain of tetrodes in Triode connection? will it be high as pentodes in triode connection?...I do have 6J11P-e 4.8w pentode and 6E6P-E 8.25w tetrodes. I think they are alsoo good drivers>..
i had put a voltage divider. just a series 440k resistor after the coupling cap..the divider formed by 440k and the grid leak resitor of 330k...is it okay with this or i put the divider before coupling cap?
I've lowered the 6n6p cathode bias to 4v and increased the ccs current to around 12ma..i came close to 1/2 b+ at output and improved the sound...bass is hard and tight but a little weak on highs...I use 2sk1341 Mosfet (900v.6A, 100w) with a ciss of 980, Coss of 400 and Crss of 165. Is it good for this design? the ccs mosfet K560 has a higher wattage and capacitances but i think ,it cannot affect since it is only a CCS...
I've also tried using 6N1P's on parallel as Tony suggest but sound is dull..so i reverted it back to 6n6p..... on the next sitting ...i will try to use a pentode and tetrodes,,triode connected in place of 6n6p and see if the sound will be more improved...
BTW, what will be expected gain of tetrodes in Triode connection? will it be high as pentodes in triode connection?...I do have 6J11P-e 4.8w pentode and 6E6P-E 8.25w tetrodes. I think they are alsoo good drivers>..
yes 6j11p is somewhat similar to e280f, D3a, e180f etc.... thanks for the info..
6E6P-e is similar to 6e5p but lower plate voltage and lower wattage..I have the datasheet attached..
im planning to use 6j11p-e as a single driver no more 6n1p prestage...like mosfet follies..however i will try 6e6p as anothe replacement of 6n6p in triode mode...still have high gain but a voltage divider is proven effective in some ways...
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