I haven't made this, but in JFET compressor circuits I've had good results with a 2N5457 in place of the 2SK30A. Mind the pinout - they're different. If you're going to do a lot of Japanese circuits I do recommend getting some 2SK30As - the ones I got from Tayda work fine.
Years ago I built a verified layout. It sounded clean without any swell effect, though I checked every single spot a lot of time and changed parts it never worked. I hope this will be fine, but I have to wait somebody else will try it, sorry. I will just compare it with the schematic in case there is some mistake. I really would like to build this effect because it's something different from drive and modulation.
Hi, if i am not mistaken, you are right and the 3.3k is missing and could probably be placed between positions (k,21) and (m,21) . Also Attack 1 should be removed and merged (soldered) with attack2, and then attack 3 should be on the row N on the right side of the layout, ex. at (N,22) under the link that should then be isolated (or adding a 23th column and attack 3 at (N,23)). finally, maybe not causing any problem, the resistors voltage divider are 22k on the schematic whereas they are 220k on the layout. first time here, hoping not misleading you. please check by yourself if i am right.
The layout is updated. Added the missing 3,3k resistor and corrected the positions for the Attack pads. Had to shift a few things around to avoid another column though...
Thanks guys, have made changes to my board!! I now have sound with some kind of effect. Not sure what the trimmer does as it doesn't seem to make any difference to the effect. Also, I have to admit, I am using a TL061 and a 5v1 zener until parts arrive.
Getting somewhere now!! Socketed what was the 220k voltage divider and stuck on 82k as it gives the Sens pot a better sweep. Using lower hfe transistors (around 150) and its working as expected. I would say verified!
Thanks Ian. I picked up some MPSA06 and an 82k resistor so will give that a crack. I think i saw elsewhere suggestion of using BC549 instead so will keep that as another backup if this doesnt help :)
Hey Ian, swapped the resistor and the transistors and seems to be working now. The effect seems to be minor (not a long fade in) unless knobs are at full particularly the sens knob and even then its a quick fade in. Is that the case or should i be able to dial in a longer fade in?
That sounds about right. It could be worth trying slightly higher gain transistors or change the 82k resistor for a trimmer (or both). I didnt mess around with mine much.
I built this as is and am confused about how to wire the third attack leg. I'm not sure if the layout is current with the comments regarding connecting 1 and 2; I've tried multiple configurations and still can't get it to work. Any help would be much appreciated!
Awesome! are there any recommendations for a potential substitutes for 2SK30A? might give this one a go
ReplyDeleteIt looks like Tayda has 'em.
DeleteI haven't made this, but in JFET compressor circuits I've had good results with a 2N5457 in place of the 2SK30A. Mind the pinout - they're different. If you're going to do a lot of Japanese circuits I do recommend getting some 2SK30As - the ones I got from Tayda work fine.
DeleteYeah, I saw that the 5457 was often a suitable replacement.
DeleteYears ago I built a verified layout. It sounded clean without any swell effect, though I checked every single spot a lot of time and changed parts it never worked. I hope this will be fine, but I have to wait somebody else will try it, sorry. I will just compare it with the schematic in case there is some mistake.
ReplyDeleteI really would like to build this effect because it's something different from drive and modulation.
I've made a start so will let you know later
ReplyDeleteCan't get this one to fly. I can see differences between the layout and schematic but that could be my lack of understanding. Anyone care to chip in?
Delete3k3 resistor missing from d1 to +9v?
DeleteHi, if i am not mistaken, you are right and the 3.3k is missing and could probably be placed between positions (k,21) and (m,21) . Also Attack 1 should be removed and merged (soldered) with attack2, and then attack 3 should be on the row N on the right side of the layout, ex. at (N,22) under the link that should then be isolated (or adding a 23th column and attack 3 at (N,23)). finally, maybe not causing any problem, the resistors voltage divider are 22k on the schematic whereas they are 220k on the layout. first time here, hoping not misleading you. please check by yourself if i am right.
ReplyDeleteThe layout is updated. Added the missing 3,3k resistor and corrected the positions for the Attack pads. Had to shift a few things around to avoid another column though...
ReplyDeleteThanks guys, have made changes to my board!! I now have sound with some kind of effect. Not sure what the trimmer does as it doesn't seem to make any difference to the effect. Also, I have to admit, I am using a TL061 and a 5v1 zener until parts arrive.
ReplyDeleteGetting somewhere now!! Socketed what was the 220k voltage divider and stuck on 82k as it gives the Sens pot a better sweep. Using lower hfe transistors (around 150) and its working as expected. I would say verified!
ReplyDeleteAwesome Ian!
DeleteCorrected the values for the Vref resistors. And it is now TAGGED.
Just finished it. Work well! Thanks fuzzhead.
ReplyDeleteJust checking should attack 1&2 be on row O and attack 3 be row N or vica versa?
ReplyDeleteIm asking as i have no audible swell. If i have sens at extreme it makes no sound but any other setting it will make sound but no swell
DeleteIm Using 2n3904 and a 2sk30a
DeleteHi Nath87, I used lower hfe transistors (MPSA05/06 I think). I also reduced the bottom left 220K resistor to around 82K and that got it working.
DeleteThanks Ian. I picked up some MPSA06 and an 82k resistor so will give that a crack. I think i saw elsewhere suggestion of using BC549 instead so will keep that as another backup if this doesnt help :)
DeleteHey Ian, swapped the resistor and the transistors and seems to be working now. The effect seems to be minor (not a long fade in) unless knobs are at full particularly the sens knob and even then its a quick fade in. Is that the case or should i be able to dial in a longer fade in?
ReplyDeleteThat sounds about right. It could be worth trying slightly higher gain transistors or change the 82k resistor for a trimmer (or both). I didnt mess around with mine much.
ReplyDeleteI do remember there only being a couple of usable settings. I think the original is the same.
DeleteThanks i might have a bit of a play with it at a later date but is enough to entertain me for now haha
DeleteIs it any way to add a LED responding to swelling effect?
ReplyDeleteI built this as is and am confused about how to wire the third attack leg. I'm not sure if the layout is current with the comments regarding connecting 1 and 2; I've tried multiple configurations and still can't get it to work. Any help would be much appreciated!
ReplyDeleteThe third leg is not connected?
ReplyDelete