knottypine wrote:Could I use 2N5457 in lieu of J201?
May be worth trying
knottypine wrote:How about BS170 MOSfet?
Probably won't work
modman wrote: ↑Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...
I tried to adapt the circuit values in order to get the same stage gains using the 2n5457 Fets.
The adaption of the drain and source resistors is only possible when the supply voltage is 18 Volts.
I tried different drain and source resistors at supply voltages greater than 9 Volts.
It is at least 30 Volts requiererd to achieve the stage gain and the clipping behaviour using the 2N5457 Jfet.
Also I had to rearrange the legs on the on the J201 to DSG (not DGS) to get Output. So I am not sure if the pin out on the strip board layout is correct
Overall more usable gain and more noticeable bass.
Manfred wrote:I tried to adapt the circuit values in order to get the same stage gains using the 2n5457 Fets.
The adaption of the drain and source resistors is only possible when the supply voltage is 18 Volts.
However, modding it to Wampler Plexithingie should not be the subject of this thread.
Also, whatever the builder says, don't believe him until you seen traces and values.
knottypine wrote:
Kinda curious why my bass and treble boost when the knobs are CCW
Reverse your lug 1 and 3 connections on your pot, and the jumpers if you installed them.
modman wrote:
Manfred wrote:I tried to adapt the circuit values in order to get the same stage gains using the 2n5457 Fets.
The adaption of the drain and source resistors is only possible when the supply voltage is 18 Volts.
However, modding it to Wampler Plexithingie should not be the subject of this thread.
Also, whatever the builder says, don't believe him until you seen traces and values.
We actually started with traces, and eventually got measured values. Benson only came in a made a few small clarifications at the end.
The schematic I last posted should be accurate.
But you're not wrong, and as I stated earlier, nothing revolutionary in this pedal.
knottypine wrote:Is there a suggested voltage for Q1?
Pedal sounds pretty nice in front of my Music Man with Bass, Mid, and Treble set to 5
~5V, or if you have a bunch of J201, set the source resistance to 12K and swap JFETs until you get one sit at 5V at the source. This will achieve a closer sonic result than just changing the source resistance to achieve 5V for whatever JFET is in there now.