Build Your Own Clone Message Board

ill have to wait til my wife brings back the camera to post a pic, but heres the scoop.

ive got an old phaser board, the 2knob version, but when i read those instructions, its got a pic of a different board, so it must be the version before that, probably one of the early revisions? no clue really.

there are 2 pads, like the easter egg pads on the 250+ board, the first pad is right beside the out jack ground pad, and the 2nd pad is beside the trimmer. ive traced pad 1, it goes right to D2, the connection to the depth pot. and pad 1, as far as i can tell, goes to a 470k resistor, which is tied to the trimmer, R9 i believe, then after r9 it goes to one of the chips.

im just wondering if anyone knows what these 3 eyelets are for? some awesome mod keith built into this pcb and never told anyone about? anyone figure this out before?


thanks, and ill try to post some pics this afternooon

Sounds like they go to each side of R9; is that the case?

almost the case.

thanks Morgan for the reply

the pad beside the out jack pad, that one goes to a little via, then connects to the outside leg of r9, r9 then connects to D1. the other easter egg pad (for lack of a better term), the one beside the trimmer, that one gets tied to the leftmost leg of the trimmer, then to R2, also a 470k. looks like thats the tail end of one of the phase stages? i dont know, im going to go look at the schematic again


so whats R9 doing? what wold be the effect of switching it off the depth pot?

again, thanks Morgan, and anyone who can hook a wook up

That's probably exactly right. The 2 knob phaser added a depth pot to the previous, vintage-correct, one knob phaser. The depth pot is a 470k resistor (R9) in series with a 500k pot (VR3) replacing the 1 meg resistor that controlled the depth in the vintage circuit.

R9 shouldn't actually connect to D1. I wonder if that is mislabeled on the pcb map?

R2 is part of the bias network for the input stage.

So, the easter egg next to the trimmer should have supply voltage on it. I'm not sure about the other one since it seems like D1 and R9 shouldn't connect.

my bad Morgan, there is no connection between that diode and resistor, i think i was referring to the pad for the depth pot labeled D2, not the diode.

Ok - then it sounds like it's there to put the depth pot on a switch. Not a very useful mod, since running the pot full-on is the same as the original 1 knob circuit. Back in the day, there were those whining about keeping the circuit to the original specs (hence all of those single op amps). The Easter eggs were probably put in to appease them.

right right, makes sense. maybe you were supposed to jumper them together for full depth or something. either way, i was just kinda hoping that putting it on a switch would magically give it some sort of new powers haha

thanks again Morgan, you the man