Hi guys, strange issue I’m having with a jfet clone of an Orange Graphic Mk II preamp, all is fine with a low input signal but it seems like if I bang the strings hard, or run a boost of some kind in front of the pedal, it suddenly gets very farty/bassy, and with slightly more gain.
If i touch the top of either Q1 or Q2, it goes back to normal, then if I hit the strings too hard, it seems to lock up or overload or something again, until a touch the top of the pedal. Giving the pedal a bump on the side with something solid (like another pedal) or sometimes just stomping the switch also works. The gain level or eq levels don’t appear to have any affect on this.
I’ve tried reseating the transistors and even replacing them in case I had a bad one, but no change.
Here is the build doc with schematic on page 6, in case anyone can see something amiss in the design:
I have also recorded a short video on my phone, with volume knob rolled back playing clean, then rolling the volume knob up and banging some power chords, you can kinda hear where it changes, then when the treble comes back if I touch the transistor (though it’s not as noticeable in the video as it is in real life):
I thought some days it sounded good and other days it sounded like a farty mess, would love to figure out the problem since when it’s working right, it sounds real good.
Thanks for any help
If i touch the top of either Q1 or Q2, it goes back to normal, then if I hit the strings too hard, it seems to lock up or overload or something again, until a touch the top of the pedal. Giving the pedal a bump on the side with something solid (like another pedal) or sometimes just stomping the switch also works. The gain level or eq levels don’t appear to have any affect on this.
I’ve tried reseating the transistors and even replacing them in case I had a bad one, but no change.
Here is the build doc with schematic on page 6, in case anyone can see something amiss in the design:
I have also recorded a short video on my phone, with volume knob rolled back playing clean, then rolling the volume knob up and banging some power chords, you can kinda hear where it changes, then when the treble comes back if I touch the transistor (though it’s not as noticeable in the video as it is in real life):
I thought some days it sounded good and other days it sounded like a farty mess, would love to figure out the problem since when it’s working right, it sounds real good.
Thanks for any help
