Post by defrag on Aug 28, 2006 22:33:16 GMT -5
I've modified TonePad's A/B Selector by mixing the channels by way of a 2nd 3PDT switch, adding a couple level pots & a dedicated tuner output. I'd like to add a few more features such as pulldown resistors, TB loops, a stereo patchboard for combining or passing multiple signals from stereo stompboxes etc. Here is my circuit gamefreaks.net/defrag/personal/graphics/baby.gif. I have a few questions regarding the basic design as listed below:
So I guess audio-taper log pots should be used as opposed to linear pots for level control of the channels. I've seen other circuits use 100K, 500K, & even 1M pots. How do I choose the value of my pots? I've read about muddiness the higher up we use & it just seems for a passive box 100K should do nicely but I don't exactly know why. Should I incorporate .001uF caps to help pass the high frequencies at lower output settings? (www.diyguitarist.com/PDF_Files/SoloPro.pdf)
Is my circuit good for both low-level & line-level use? Any considerations here? I'm not sure what to ask but there must be advantages as well as disadvantages in supporting both.
In all other circuits but one (www.fulltone.com/PDfFiles/AB_switcher.pdf) that I've seen, the signal-ground & LED circuit ground is shared. Then I run across a reference to an RC solution to minimize the "pop" (www.muzique.com/lab/led.htm) in higher gain circuits when the LEDs are switched. Is there a way I can isolate my existing circuit grounds & keep the same functionality. While my circuit isn't necessarily designed for high gain applications, I'd like the pedal to be as versatile as possible & wouldn't mind incorporating the RC solution to support higher gain inputs (but not necessarily).
I've read that #22 wire is the standard gauge to use. I'd like to fully shield all the runs & isolate it from the box itself but am a bit confused. I think to fully isolate the wiring, I need plastic jacks. But then I read that to properly ground everything & have the box itself provide shielding from interference, I need to ground the circuit to the box. Can you clarify this for me please?
I'd like to have current-limiting pulldown resistors on the inputs like the big-boys' pedals to maintain high impedance on the input(s) & low impedance on the output(s). But it looks like I'd need a DPDT switch to choose between 1M on the single input & 10K on the two outputs... or have the 1M on the two inputs & the 10K on the single output, depending on how I use the splitter functionality. Is there a better way or being mainly a passive box, not worth the extra switch(es) necessary?
Apparently I didn't understand shielding very well 20 years ago where only one end of a given wire is shielded. So does this imply that if I were to use shielded wires throughout the project, I simple ground out one end of each & never tie them together. I suppose its starting to sound a bit impractical to shield everything eh?
Perhaps a gated IC or a multi-transistor flip-flop of sorts would be a better solution to having a 2nd 3PDT switch. I don't know for sure as I'm juust getting back into electronics & have been reading everything I can get my hands on. It would be great to take all the best ideas & stuff them into one powerhouse do-all stomper.
TIA
So I guess audio-taper log pots should be used as opposed to linear pots for level control of the channels. I've seen other circuits use 100K, 500K, & even 1M pots. How do I choose the value of my pots? I've read about muddiness the higher up we use & it just seems for a passive box 100K should do nicely but I don't exactly know why. Should I incorporate .001uF caps to help pass the high frequencies at lower output settings? (www.diyguitarist.com/PDF_Files/SoloPro.pdf)
Is my circuit good for both low-level & line-level use? Any considerations here? I'm not sure what to ask but there must be advantages as well as disadvantages in supporting both.
In all other circuits but one (www.fulltone.com/PDfFiles/AB_switcher.pdf) that I've seen, the signal-ground & LED circuit ground is shared. Then I run across a reference to an RC solution to minimize the "pop" (www.muzique.com/lab/led.htm) in higher gain circuits when the LEDs are switched. Is there a way I can isolate my existing circuit grounds & keep the same functionality. While my circuit isn't necessarily designed for high gain applications, I'd like the pedal to be as versatile as possible & wouldn't mind incorporating the RC solution to support higher gain inputs (but not necessarily).
I've read that #22 wire is the standard gauge to use. I'd like to fully shield all the runs & isolate it from the box itself but am a bit confused. I think to fully isolate the wiring, I need plastic jacks. But then I read that to properly ground everything & have the box itself provide shielding from interference, I need to ground the circuit to the box. Can you clarify this for me please?
I'd like to have current-limiting pulldown resistors on the inputs like the big-boys' pedals to maintain high impedance on the input(s) & low impedance on the output(s). But it looks like I'd need a DPDT switch to choose between 1M on the single input & 10K on the two outputs... or have the 1M on the two inputs & the 10K on the single output, depending on how I use the splitter functionality. Is there a better way or being mainly a passive box, not worth the extra switch(es) necessary?
Apparently I didn't understand shielding very well 20 years ago where only one end of a given wire is shielded. So does this imply that if I were to use shielded wires throughout the project, I simple ground out one end of each & never tie them together. I suppose its starting to sound a bit impractical to shield everything eh?
Perhaps a gated IC or a multi-transistor flip-flop of sorts would be a better solution to having a 2nd 3PDT switch. I don't know for sure as I'm juust getting back into electronics & have been reading everything I can get my hands on. It would be great to take all the best ideas & stuff them into one powerhouse do-all stomper.
TIA
