Just in the middle of this one after Sebastian kindly sent it to me. Typically I’m missing some bits, but I should be able to finish it tomorrow. I did happen to notice there are two 10uf caps on the schematic.
The jumper on the left is carrying the amplified signal from Q1's output. Maybe it shouldn't cross the weak, high impedance input signal. This could cause oscillation because of capacitive coupling. It would be easy to move the input to the bottom.
Ben & Roseblood11's comments got me to take a second look at the layout and WOOOO BOY did I fuck that up! Revised layout has been sent to Anders. Apologies for my dumbassery—here comes Take 2.
The sweep is reasonable, but not dramatic. More subtle than I expected, but perfectly usable. The treble is tied to the gain so lowering the treble lowers the volume too, whilst the bass starts to climb more dramatically toward the end of the sweep.
I hope this works! As a quick note, if you don't have J201s on hand (I never do), try whatever DSG-pinout JFETS you've got and see how it fares.
ReplyDeleteJust in the middle of this one after Sebastian kindly sent it to me. Typically I’m missing some bits, but I should be able to finish it tomorrow. I did happen to notice there are two 10uf caps on the schematic.
ReplyDeleteGray Bench Electronics made a teardown of this one and measured the jfets: https://youtu.be/nK1w8Xt_17g?si=Ym1RTnUp1I_PYU-b&t=437
ReplyDeleteAll are set around 11.2 V.
Will try to build this in the future. Right now I have unfortunately and fortunately many outstanding projects, but this will be on my list.
The jumper on the left is carrying the amplified signal from Q1's output. Maybe it shouldn't cross the weak, high impedance input signal. This could cause oscillation because of capacitive coupling. It would be easy to move the input to the bottom.
ReplyDeleteBen & Roseblood11's comments got me to take a second look at the layout and WOOOO BOY did I fuck that up! Revised layout has been sent to Anders. Apologies for my dumbassery—here comes Take 2.
ReplyDeleteThe updated layout is up!
DeleteTag it! Sounds great!!
ReplyDeleteHi Ben, how's the treble and bass - is there a good sweep on both? Cheers
DeleteThe sweep is reasonable, but not dramatic. More subtle than I expected, but perfectly usable. The treble is tied to the gain so lowering the treble lowers the volume too, whilst the bass starts to climb more dramatically toward the end of the sweep.
DeleteThanks mate
DeleteCheers!
DeleteTagged.
This comment has been removed by the author.
ReplyDeleteWould the max1044 be compatible with this layout? I suspect it should? TIA
ReplyDeleteYeah, should be fine!
Delete