The output is 4uf but can be changed depending on the input Z or the poweramp. They run at less than a watt and after an hour aren't hot. Power supply voltage can be higher but disspation will increase.
I suspect fairly high second order distortion which gives it a nice tone.
I suspect fairly high second order distortion which gives it a nice tone.
The MOSFET is the DN2540N5-G.
I'm not sure of the minimum supply voltage. The first stage runs at 17ma. If you want lower voltage replace both 1500ohm resistors with 1000Ohm so they drop less. Gain will be lowerd.
Scott
I'm not sure of the minimum supply voltage. The first stage runs at 17ma. If you want lower voltage replace both 1500ohm resistors with 1000Ohm so they drop less. Gain will be lowerd.
Scott
Thank you for putting this up.I have long been interested in a MOSFET preamp.Will try to build this sometime before I die.If it gets next in line I could have it done by 2090 or so.
I would suggest not attempting to run the circuit on a much lower supply voltage. The reason is, that a lower supply voltage risks significant modulation of the input capacitance of the MOSFETs. Resulting in significantly increased distortion. A quick look at the DN2540N5-G datasheet indicates that the 60V supply voltage chosen by scholl seems a good figure.
After some experimentation I find these devices like 30-40ma. 17ma is to low to sound good.
I reconfigured the circuit as a SEPP buffer at 40ma on +-17V power supplies. No gain but nice sound an only 80ohm output Z.
I reconfigured the circuit as a SEPP buffer at 40ma on +-17V power supplies. No gain but nice sound an only 80ohm output Z.
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