more news from the bad stone

[lowstar]

hi folks,

hope you don´t get bored already with my stone-stories. 

i put it in a box yesterday, with an opamp-gain stage to make up for the volume-drop and a millennium bypass. used an hammond 1590c that i had lying around which had one led-hole too much, so i tried to imply a rate-led.
took the voltage off pin 14 of the lm324 in the lfo with some 2k2 (i think) in between.
took it home to try it out with bass - wow - sounds really good with bass guitar.

but i had a noticeable tick.

so today checked out where it was coming from - even with the rate-led-power disconnected, it was still there (but only 50% as loud).
so i used shielded wire for the rate pot coming off point >i< on the board. this already made things alot quieter; then i used shielded wire for the led-power wire, and that did the trick pretty much. if you crank everything too the max on the amp, you can still hear a very faint ticking, but if you strum a chord in this situation, you´ll loose your hearing anyway. 

so, basically i wanted to let you know a) that this is a very useful build for bass players
                                                      and b) how to imply a led blinking at the rate of the lfo

cheers,
lowstar

p.s.: here´s the link to the schem i´m talking about, just to be correct  http://topopiccione.atspace.com/pjimages/EHBadStone.sch.gif

[bioroids]

Cool.

How much hiss noise does it have?

Luck

Miguel

[Marcos - Munky]

Does your Feedback pot works correctly? I built it using the same schematic and layout, but the pot doesn't do anything very noticeable. Also, did you just took the voltage out from the pin 14 and connected to a LED with a 2k2 resistor between them?

[lowstar]

Cool.

How much hiss noise does it have?

Luck

Miguel

most hiss is induced in the last 25% of travel of the feedback pot, where the effect sounds really spaced out (or stoned, too stay close to the name here).
but the fx itself has some background hiss even with the feedback pot turned all the way to zero, yes. you definitely hear when it´s turned on hiss-wise when you use earphones. thru a guitar amp, i think it wouldn´t be very noticeable. thru a bass amp, i have to try it out. my next rehearsal will be on sunday. 

btw, i used 1MC pot (revlog) for the rate control, and it will be a 100KC for feedback (i have to order that one, so now it´s a 100Klog wired backwards).

Does your Feedback pot works correctly? I built it using the same schematic and layout, but the pot doesn't do anything very noticeable. Also, did you just took the voltage out from the pin 14 and connected to a LED with a 2k2 resistor between them?

now my feedback pot works correctly. but as i stated in one of my former posts concerning this fx, it took me half a year to find the bug, and before, my feedback pot didn´t work correctly, either. the output of IC D had a bad solder trace, which was not easy to see, i even had covered it with solder cause it was from a batch of badly etched pcb´s (my first ones  )
it did phase though, but only very subtly...that´s why it took so long, cause i was never sure if it was intended to sound like that or not (never saw a real bad stone in my life). i was finally sure when i listened closer to the sound samples on alex´s page, though. so we notice: sound samples of diy fx are a very good thing. 

if you take a normal log pot and don´t wire it backwards, all the change will happen in the last bit of pot rotation, maybe that´s the case with your bad stone ? i´d wire it in reverse if i were you, just to make sure.

as for the led: yes, i just ran a wire off the second next resistor to pin 14 of the lm324 (R47), so i could take it from the upper side of the board, and put a suitable resitor in between, the cathode to gnd. so it´s on all the time, but that´s ok with me, i have an extra indicator light for fx on. it would be even more  beautiful to have the led fade in and out smoother, but that would require an additional little board in there, i guess.

when you do the led thingie, you probably have to shield the wire - mine was ticking very noticeable until i shielded that wire (and the rate pot).

cheers,
lowstar