Quote:
Originally Posted by dave cox
I didn't sim, honest !
ac gain R4/R5
dc gain R4/(R5+R6)
T2 could be anything with lots of gain as its doing most of the work, if you ignore the the input impedance! (which probably could be a lot more that 1M with suitable R2)
It looks quite neat to me.
Is 1M a standard ?
dc
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You can set the gain (within reason, around 10x is probably Ok for simple low output ceramic cartridge preamp) by choosing R5 using the formula above. For 10x use 1k. The output dc level can then be set by playing with R6- increase it to drop the output dc, reduce it to increase. A useful starting point is around the value where the sum of R5+R6 is around 2.2k (about what it was with the original values for R5, R6).
(I did cheat and SPICE it
)