More noob questions

[jfrey]

Making this my official noob question thread - before every thread in the DIY forum is from me...

Q1: Looking at this:
http://www.beavisaudio.com/techpages/Pe ... /index.htm

Is there a reason they are using all mono jacks? Instead of having the stereo input jack? Wouldn't you want it to have the same jack as a switch functionality as usual? Or does the way this is set up somehow accomplish the same thing?

[orcrist]

the choice of jacks doesn't really matter for that circuit. stereo jacks are used in mono pedals to conserve battery life...usually set up so that the ground from the power supply is only connected to the circuit when a mono plug is inserted into the jack.

in the case of this effects/feedback looper, the only thing that requires power is the led, which is turned on and off by the footswitch.

[jfrey]

Ok, I see. Thank you.

[Jero]

the choice of jacks doesn't really matter for that circuit. stereo jacks are used in mono pedals to conserve battery life...usually set up so that the ground from the power supply is only connected to the circuit when a mono plug is inserted into the jack.
in the case of this effects/feedback looper, the only thing that requires power is the led, which is turned on and off by the footswitch.

[jfrey]

Q2: So I got a bunch of opto parts and I'd like to know how to add light sensitivity to an effect, but I don't get the difference between the optocouplers and LDRs or when you use one or the other or if you use both. Anyone know that could explain it to me?

[orcrist]

as far as i know, optocouplers incorporate ldr's in them. to make your own light control, you'd wrap together an led and ldr (facing each other) in electrical tape or heat shrink tubing or whatever. an optocoupler is just the commercial/pre-made version of that.

to use an optocoupler (bought or homemade) you will need some kind of circuitry to make the led blink or dim. or use a potentiometer as a voltage divider to supply a control voltage that determines the brightness of the led. and use the ldr portion in place of a resistor or potentiometer (e.g. a tone pot) in the circuit.

or you can just use an ldr (replacing a resistor/potentiometer) and mount it to the enclosure so that you can supply your own light source, cover it with your hand or foot, etc.

hope this helps and is somewhat understandable.

[jfrey]

Ok, to try to summarize an idea from what you said, If I were to replace a pot with an LDR, the circuit would treat it in the same way it would a pot but using light as a control correct?

Or, would I use an Optocoupler if it has an LDR in it anyway?

and,
Q3: Say you wanted to have multiple LEDs as an indicator instead of just one. Would you set them up each individually with a resistor? Or use one resistor connected to all of them? And, if so would the resistor's value have to be different than it would normally be for one LED?

[mysteriousj]

Do you mean optocoupler or vactrol? I think you're after a vactrol, which is a LDR and LED in the same package. Optocoupler normally means something else, eg phototransitor they are bit more complicated best to start with vactrol... So yip, you can replace a pot with an vactrol easy, although i'm not sure of the point sometimes? (A vactrol is just an LDR and an LED in one package, you can make one yourself {buy a LED and LDR and put them together and wrap in tape} or just buy a vactrol, but they are expensive ~$5 for a vtl5c3. One of the main uses of vatrol is in modulation circuits say a tremolo where you have an LFO, which outputs a voltage in a waveform. You can then use this voltage to turn the LED off and on. This Light from the LED adjusts the LDRs resistance so when the LED is on you typically get 5kohms and when the LED is off you get 1Mohm, (and you get stuff inbetween depending on how bright the LED is, it's not just "on and off" of course).

Okay so if you want to replace a pot with a vactrol you can but usually there's not much point.. (i'm not sure what you're trying to do?) Because basically you still need a way of adjusting the current through the LED to change the brightness (ie with a with a pot) so it just makes things more complicted for no reason. There's one exception when you say want to put the LDR on the outside of your stompbox and control the light it by shading it with your foot or something. What are you trying to do, though?

[jfrey]

There's one exception when you say want to put the LDR on the outside of your stompbox and control the light it by shading it with your foot or something.

This.

[mysteriousj]

In that case then you just need a LDR. It'll work best when you're using just two lugs of a pot and not 3, because it's ..only one resistor(then you'd have to fix the other resistor in the voltage divider)... So if you have a multimeter cover your ldr from light and measure it's resistance. If say you have to replace a 50K pot and your ldr is something like 1Mohm or something you can put a resistor in parallel with it say 50K to get around a max of 50K. Just play around with it I guess.

[jfrey]

New question, What should my next project be?

So far I have built a culturejam D.E.D., a Silver Crank/Dark Boost/Bazz Fuss (although I couldn't get it working on my own and had to get help from morange), and a feedback looper with an xlr input.

[mysteriousj]

have you heard of madbean? He's got some cool projects. http://www.madbeanpedals.com/projects/index.html Although there's too many to choose from, I couldn't really recommend just one. I love the analog delay but it's a bigger project though.

If you're into vero check out this page http://www.sabrodesign.com/?page_id=4 heaps of layouts

[Toonster]

I didn't know madbean yet, but it is in the bookmarks now!

[jfrey]

Those are both cool. Anything with perf layouts though?

[mysteriousj]

try this topic on freestompboxes, it's mostly simple tagboard but yeah the same deal as perf
http://www.freestompboxes.org/viewtopic.php?f=13&t=8193