Another easyvibe question - led/ldr positions-where do they go?

[jimbob]

Ok i have this about finished but I cant see how I place the 1-4 led/ldr combo's. I can see how and where the ldrs would be placed. I wouldnt think that it would matter. And.. I also see according to the layout that the ldr portion goes on the lower/south? part of the board, but, what about the led part of it? Where does the + or- end of the led go or does it matter? I would assume it does. I didnt see any squares or anything else to distinguish the answer.


Anyone?


Thanks

[petemoore]

Where does the + or- end of the led go or does it matter? I would assume it does. I didnt see any squares or anything else to distinguish the answer.
  Here's how I did it...
  The LDR's connect...either way around/non polarized like resistors.
  The LED's need to be the correct way around...I just took a free' LED I had laying around, put that on the diode checker of the DMM to find which way the little flat spot 'reads'...then used that to put a mark or designate the mark on the LDR/LED photocells I used [sealed LED/LDR's]...basically I just got the flat spot leg of the LED to go where the line is on the schematic, and connected the other legs of the LEDs to the remaining LED connection points...and connected an LDR across each phase stages LDR connection points...
  I used a DMM and an LED to figure out what's what inside the LED/LDR...which connections are which for the LED 'inside' by comparing the readings to an LED I Could see.
  But it might say on the data sheet or soemwhere...which connection a *dot on the body of the LDR/LED photocell *refers to....if it has a dot...if not I'd put a dot or marker there.

[Torchy]

[captntasty]

Dude, I was about to jump on you with "whaddaya mean? of course it says where + and - on the LEDs are!", but thought better of it and went to the layout and sure enuff....  good question, man... I puzzled over this for a while and followed the maze of traces and I can't believe this question doesn't come up every other day - there's got to be something on this from a previous post ------- http://www.diystompboxes.com/smfforum/index.php?topic=44804.msg326708
I guess the logic is that the power is coming from C9 -> LEDS (daisy chained) -> R18 as the limiting resistor.  I'm so used to seeing the limiting resistor before an indicator LED that I never thought that it could be tacked on the end to limit current...  is this how this section of the circuit works - with the limiting resistor at the end of the chain rather than the start?

edit: I guess Torchy's trigger finger is way faster than mine 

[captntasty]

I guess the logic is that the power is coming from C9 -> LEDS (daisy chained) -> R18 as the limiting resistor.

I guess I would be wrong

[jimbob]

Great! Thanks for the replies. Ill give it another try. So far i get clean sound for a few seconds- then distortion - then nothing. I think Ill look it over a few more times and see if i can get it going. While doing this im also building the great cheddar, dod 440 filter , another ts808 with basic audio mods and GGG's new layout, and a few more projects. Keeping busy!

[jimbob]

Btw- this might be a dumd question- Torchy- what does the  "k and a" stand for? - or +?

[Torchy]

Standard notation - k = cathode, a = anode. With an led the anode is the positive side.
When you look at a diode symbol, the arrowhead and bar makes a "k" shape - thats the cathode 

Oh, and chek here for a short ...

[jimbob]

very cool! thanks

[Torchy]

For debugging this may help




And this for checking power routing ...