Favorite Optocoupler?

[wokeupfalling]

I am building a remote expression pedal - and I am looking for some feedback on Optocouplers.

What's the best one out there?  Namely, what's the best brand...  Vactec, Silonex, Clairex?  Does it matter?

For my use, I don't know how picky I should be.  On the other hand, I don't mind paying for quality.

Opinions?  Please?

Thanks ~

[Joe Kramer]

Hey WUF,

Silonex NSL-32 is pretty reliable.  I've used it for compressors, phasers, tremolos, noise gates.  Small footprint, low current consumption.  Available through Allied Electronics, but maybe elsewhere too.  Be careful when experimenting, because the LED is sensitive to overvoltage/current.  I've popped a couple, so I buy extras!

Regards,
Joe

[darron]

i have no experience with them, but i've read some of the datasheets. they tell you approximately the range in resistance for extremes of light/dark as well as their ratings. it seems what you should mostly consider when selecting one is how much photo-memory you want? some of them act smoother (more memory), which sounds like it would be quite beneficial, except that you couldn't get the same defined edges when you wanted to reverse the direction.

i was just looking at the stock at smallbearelec.com and i think i'll make an order (:

the pdf here is an excellent read!

http://www.datasheetcatalog.com/datasheets_pdf/V/T/L/5/VTL5C3.shtml

[oldrocker]

I always make my own.  But I know some don't like to.  It always works for me though.  LED\LDR and shrink tube.  I made a DOD 280, Easyvibe, Ugly Face, Flatline Comp with that setup and never had any issues.

[darron]

I always make my own.  But I know some don't like to.  It always works for me though.  LED\LDR and shrink tube.  I made a DOD 280, Easyvibe, Ugly Face, Flatline Comp with that setup and never had any issues.

i think you might get that extra bit of satisfaction building your own. it strikes me that a bought one though will give you more consistent results and they will have experimented to find exactly what is most efficient. my main concern would be fine tuning the pedal. do the results vary much when you use the circuit with the led/ldr outside of the box in daylight (even while in heat shrink)?

what colour/type of led do you use? i've heard colours vary heaps. i'd probably just try a 5mm high intensity white led?

[Johan]

I always make my own.  But I know some don't like to.  It always works for me though.  LED\LDR and shrink tube.  I made a DOD 280, Easyvibe, Ugly Face, Flatline Comp with that setup and never had any issues.

i think you might get that extra bit of satisfaction building your own. it strikes me that a bought one though will give you more consistent results and they will have experimented to find exactly what is most efficient. my main concern would be fine tuning the pedal. do the results vary much when you use the circuit with the led/ldr outside of the box in daylight (even while in heat shrink)?

what colour/type of led do you use? i've heard colours vary heaps. i'd probably just try a 5mm high intensity white led?

the commercial ones wary quite a lot and needs to be pretested if you want to build many units and have consistent results. making your own is easy and you can then preselect the LED. working with only 9 volts, using high intensity ones probably isn't going to give the best results...they need more voltage to give smooth responce, especially if you want anything other than on/off..I prefere red LEDs
if you shrinkwrap the homemade optocoupler it shouldn't matter if its inside the box or not. if you do it "naked" on an pcb, it obviously needs to be inside a closed box to work properly
j

[oldrocker]

Yes experimentation is the key.  Many LED's and LDR's are different.  I bought the variety pack LDR's so I could pick which ones were closest to what was called out for.  I have had success with red and yellow LED's.  For the Easyvibe red LED's worked great for me.  Some I'm sure will disagree with making them but I'm just saying that they worked great for me.  I'll even go as far to say that when I did finally buy a Vactol optocoupler it was defective.  Not a good reason not to use them I know but I also enjoy making my own.

[Joe Kramer]

Rolling your own comes in handy when you want something that's not commercially available.  Here's a quad LDR I used in a phaser/vibe circuit  ( under "Joe's LDR module," four pix):

http://aronnelson.com/gallery/Schematics-etc?page=5

In pic #3, the end pieces are small chunks of neoprene rubber, which seal the ends when the heat shrink shrinks. . . .

[darron]

Rolling your own comes in handy when you want something that's not commercially available.  Here's a quad LDR I used in a phaser/vibe circuit  ( under "Joe's LDR module," four pix):

http://aronnelson.com/gallery/Schematics-etc?page=5

In pic #3, the end pieces are small chunks of neoprene rubber, which seal the ends when the heat shrink shrinks. . . .

now that's pretty fricken cool! takes up a lot of space though. i might give that a shot (:

i was thinking that if i built one i might run a couple in parallel to lessen the resistance. are there any 'smoothing' advantages also?

so that's a clear to red LED? doesn't most of the light from those come out of the top?

cool thread! (: sorry to take it over a bit

[Joe Kramer]

Hey Darron,

Thanks!  You're right, it takes up some space, but way less than four individual NSL-32/Vactrols, and way less current too.

That is a clear/red LED.  I think I chose that one for brightness and low voltage.  A lot of light did come out the top, but the DIY solution was to take some sandpaper and rough up the whole thing to diffuse it.  Works fine.

I've never tried running LDR cells in parallel, but I guess you could do it.  A lot of circuits use a fixed resistor in parallel to the LDR to set a sort of max resistance point.

[wokeupfalling]

So are a lot of you saying that making your own will yield a more favorable outcome?

I guess I figured that buying an Optocoupler, it would be the best matched components and that a model number would equal consistency.  I also assume that most are tested??  For the price, they better be top notch, no?

I am already in-deep with the rest of my design, so I feel that time-wise, making my own "may" not be plan A.

So...  Banking on my above assumptions being true, what branded Optocoupler is the crowd favorite?  Again, I will be using this as variable resistance controlled by an expression pedal.  I need something that will track(?) smoothly.

Otherwise, if Optocoupler = Poor Quality, then count me out...

Thanks!!

PS. That quad is awesome Joe!

[Shepherd]

the commercial ones wary quite a lot and needs to be pretested

Yes experimentation is the key.  Many LED's and LDR's are different. 

[wokeupfalling]

I guess the reason I'm asking here, is to avoid buying every known option...  I can't exactly afford to try everything...

There has to a brand that is consistent and puts out quality, tested optocouplers... 

Is there no such brand or manufacturer?

[Joe Kramer]

Hey WUF,

Once again, my fave is Silonex NSL-32, but my reasons for liking it are particular to me.  I like the fact that they're smaller than Vactrols, though the performance is similar in many other respects.  As far as quality, if you mean audio quality, you really can't go wrong with almost any LDR, hand-rolled or store-bought, since it has no effect on the sound any more than a common fixed resistor.  After that, it's all about how you set up the control voltage/current to the LED.  There are variations among different LDRs, such as on and off speeds, min and max resistance, and matching between units.  But after you've settled on a certain model, you're going to wind up making a few circuit adjustments to accommodate those variations anyway.  If you possibly can, I'd say get a hold of one of each, NSL-32, Vactrol, or hand-made so you can come to your own conclusion.  If you can't manage that, go with what's easiest to get and fits your budget.  Then worry about getting it to work for you.  That's one of the cool things about opto-couplers--they're pretty forgiving and flexible and easy to work with for how much power they can have in a circuit.

And thanks for the compliment!

Regards,
Joe