Picture an easy vibe?

[bifbangpow]

Ready to build Holliss' Easy Vibe. Noticed there are 6 3mm LEDS listed... planning on drilling the case myself.
(not sure why there are 6 LEDs in the first place.)

Does anyone have a picture of their finished pedal I can use to get an idea of what this will look like?
Also what's a good drill bit size for the 3mm led holes?

[Kipper4]

Looks like two leds are in the power supply for biasing the op amps.
The other four are in vactrols. (Led/LDR combination. See schematic.)
All these would be internal. Soldered to the pcb.

I usually drill with a 3mm bit.
I hope it goes well.

[bifbangpow]

Looks like two leds are in the power supply for biasing the op amps.
The other four are in vactrols. (Led/LDR combination. See schematic.)
All these would be internal. Soldered to the pcb.

I usually drill with a 3mm bit.
I hope it goes well.

I've never done the vactrol thing before.  So I just touch the led head to the head of the vactrol? 
Also one more question.  The "drive" component... on the ccircuit board the pins seem to go in a straight three point line, but every ik trimmer I buy has three legs in a triangular shape.  Should I just bend one, or am I purchasing the wrong component?

[JerS]

Just to be clear, the LEDs shown in the schematic are not intended to be the effect indicator LED on the outside of the enclosure. The 2 LEDs in the power section remain lit the whole time and the ones with the LDRs flash in sequence with the LFO rate.

Maybe you already knew all this, nut I thought I'd share just in case.

Cheers - Jeremy

[pinkjimiphoton]

Looks like two leds are in the power supply for biasing the op amps.
The other four are in vactrols. (Led/LDR combination. See schematic.)
All these would be internal. Soldered to the pcb.

I usually drill with a 3mm bit.
I hope it goes well.

I've never done the vactrol thing before.  So I just touch the led head to the head of the vactrol? 

u don't need the leds if using a vactrol. (yes you do still need the ones in the power supply) if you are using a vactrol, one pin is marked with a +, this is the + lead of the internal led. one side is the two legs of the led, and the other side is the 2 (or three, some are center tapped, so don't worry about the middle one. you can clip it off or insulate it incase ya harvest it for future builds.)

if you don't have vactrols, you need to use led's and ldr's... light dependent resistors. the led's are polarized... the long leg must go in the hole marked +, usually square on a pcb. the ldr's aren't polarized. in this case, take the led and ldr and point them at each other. do it in a dark room and play with it til you get the best effect happening, then turn on the lights and wrap it up in electrical tape or whatever.
i find the best  match seems to be the water clear ultrabrite jumbo 10mm led's for this kinda use, but the regular 5mm work ok and are easier to manage. in a vibe that bigger led ramps up and down slower imho, more like an incandescent light.

once it's in the box, i don't think it matters so much about sealing them off from light. if they are pointed at each other right they should work well.

Also one more question.  The "drive" component... on the ccircuit board the pins seem to go in a straight three point line, but every ik trimmer I buy has three legs in a triangular shape.  Should I just bend one, or am I purchasing the wrong component?

that's because they used to make trimmers that were like that too, but more likely so you can move that to an actual pot, lets you fine tune the effect of the pedal if you need to accomodate for low power situations or if ya want a little more or less "throb". i'd mount it in the case with a normal pot if it was me, but...

[rutabaga bob]

*see Jimi's post below*

RE-EDIT: after putting some voltage into the led, I measured the resistance for each half AND across the outer lugs.  I am wrong.  My apologies.

[pinkjimiphoton]

really? thanks larry... i guess i should reexamine a couple builds. when i looked up the data sheet on mine it just showed it as being a center tap for the ldr. i used the two outside legs and left the middle unconnected but intact in case i ever need to scrounge the parts for something else.

look on page 47 of this: http://pdf1.alldatasheet.com/datasheet-pdf/view/84398/PERKINELMER/VTL5C10.html

its most definitely a center tap, it doesn't show two separate ldrs, unless i'm mistaken. it's almost set up like a pot, in fact.

[PRR]

If you ignore (or snip) the LDR CT, you have one LDR of double the value.

Wasteful but not useless.

[pinkjimiphoton]

so it IS a center tap then? far out.
i may have to revisit one of my builds and see if it works better with the center tap being used now.
i just thought it was so you could use it at half its normal resistance... or is it an impedance in a case like this?

thanks for the clarification paul

my bad larry!!! carry on!!!

[rutabaga bob]

It's me, not you.

[PRR]

> thought it was so you could use it at half its normal resistance...

It is for controlling two things at once. Stereo channels comes to mind.

It apparently "is" one big blot of LDR with an extra wire. (Must be some mask difference also.) Likely there is another single-gang part of same chemistry with half the resistance. All moot now because these parts are going out of style.

[pinkjimiphoton]

> thought it was so you could use it at half its normal resistance...

It is for controlling two things at once. Stereo channels comes to mind.

It apparently "is" one big blot of LDR with an extra wire. (Must be some mask difference also.) Likely there is another single-gang part of same chemistry with half the resistance. All moot now because these parts are going out of style.

i respectfully disagree, if it were for stereo use it would have two active elements (the LED) not one.

it appears to be more so you can have two preset levels to it to me, but i know far less about this stuff than you.

i could see it being set up so one control source can control two separate resistors, but again, it's a center tap.
when i measured it with my meter it was just about dead nuts between the two outer leads in the middle.
but i still looked it up. i think larry thought it was an anode cuz it had an arrow on the end like on a pot. but a resistor can't have a positive or negative end. even IF center tapped.

i mean the number of possibilities seems pretty good... you could make it so half way up it starts another process, or completes another circuit or triggers something or whatever. i would imagine you could even mess with the taper of the part by adding parallel resistance to one half or the other just like on a potentiometer or whatever... perhaps the first half of the sweep is too long, add a pot in there and bunch up the sweep some?
stuff like that.

looking at the data sheet doesn't really seem to help, tho i only gave it a cursory glance. it appears tho that the two outer legs are meant to be the active ones and the middle is so you can monkey with it if you need to.

and these are easier to find than the 4 lead versions. if ya read the data sheet, it also becomes possible to mimic incandescent lamps with these, as some respond quicker or slower to light. pretty neat technology and very useful in some things..
my systech phaser has 4 of them and when i got it one was dead.  very univibe-y in part cuz of the "swing" to light the lamp... you can apparently specify rise and fall times for the brightness, which is very cool.

anyways, thanks for giving me the opportunity to learn a little, and my apologies for highjacking the thread.

[PRR]

> i only gave it a cursory glance.

Might deserve more than a glance?

They do not come out and say. A glance plus a thought may bring insight.

VTL5C3/2 is a VTL5C3 plus a contact in the middle of the photo resistor.

You "could" do this yourself with plain LDRs. Remove the clear sealing, without injuring the PbS, or poisoning yourself or the environment. Run a thin strip of conductive paint down the exact center and contrive a contact.

VTL5C3 is 30K @ 1mA. VTL5C3/2 is 55K @ 1mA. "Double", except they covered some active-stuff (about 4% each half) with the conductive contact.

The *ratio* is always 1:1 (+/-20%). So it is not a variable divider. It is two semi-matched common-control variable resistors.

This image shows a Stereo Volume Control.

One current cuts both channels. This is not a great "Volume" control because it will not go to Zero output. However a stereo limiter with 30dB attenuation is a practical thing. Conversely a stereo noise-gate with 30dB duck is plenty. While it would not be absurd to just use a second LED+LDR, you do like to save the buck and the 1.7V. Also the two-halves LDR is "sure" to have both halves from the same batch and dip and match closely from new and over time.

The simple center-tap does rule-out using some of the simpler application notes for stereo. Page 58 (paper) fig 1A works, but 1b 1c 1d need both ends free. 1e readily re-rigs, but 1f does not. Fig 2 can be expanded to linked-stereo 3X3 with dual LDRs, and the simplification of the LED side may be appreciable. Fig 5, 8a, and 9 are basic limiters and because one end of the LDR is common (to ground), the dual LDR can be used.

There is another (mono) application. The R/I curve is, uh, curved. Two LDRs on one LED, you measure the second and servo the LED to get the desired resistance, making the curve real linear. This is Fig 10. Eout/Ein is always Vc/Vref.

[pinkjimiphoton]

paul, thank you man.
most of this is way over my head. i will likely forever be a monkey with a breadboard.
i wish i had the time for more than a cursory glance. but that is very very rare.
sometimes the need to know if an application will work trumps (god i hate that word) the need to understand it. at least for me at the present time.
the devil may be in the details, but to me when i looked, i saw a center tap.
in the application i needed, i ignored it, in fact the person who sent it to me to try one of their boards sent me one with the instruction to either ignore or remove the middle tap. i opted to leave it in case i ever cannibalize it.
but i don't need it for that, i don't at this time need it for a "stereo" limiter, tho i have praise for those who do.
call me short sighted and you'll be right, but sometimes all ya wanna know is if something may work.
while some may obsess over exact replacements or corksniffer parts all i care about is if it will work or not.
so... (i guess 40 pages in is pretty cursory) thanks for the info,
but in the end, to me, at my present state of knowledge, a center tap is a center tap.
peace man

[bifbangpow]

that's because they used to make trimmers that were like that too, but more likely so you can move that to an actual pot, lets you fine tune the effect of the pedal if you need to accomodate for low power situations or if ya want a little more or less "throb". i'd mount it in the case with a normal pot if it was me, but...

Since I all ready drilled the holes for my case, I'm hoping to keep the on-board trimmer.  Can I use my three pronged internal trimmer? It's prongs are layed out in a triangular pattern, can i just bend them to fit? or is there a different trimmer I can get?

[thermionix]

Can I use my three pronged internal trimmer? It's prongs are layed out in a triangular pattern, can i just bend them to fit? or is there a different trimmer I can get?

Are the legs long enough to bend and reach the holes on the board?  If so, I'd say go for it.  If not, maybe add a short piece of solid wire or component lead scrap to the wiper leg, bend the other two legs out, and stand the trimmer up on the board.  You can get another trimmer that would fit 3 holes in a line, but might as well use what you have on hand and save a couple bucks.

[bifbangpow]

Can I use my three pronged internal trimmer? It's prongs are layed out in a triangular pattern, can i just bend them to fit? or is there a different trimmer I can get?

Are the legs long enough to bend and reach the holes on the board?  If so, I'd say go for it.  If not, maybe add a short piece of solid wire or component lead scrap to the wiper leg, bend the other two legs out, and stand the trimmer up on the board.  You can get another trimmer that would fit 3 holes in a line, but might as well use what you have on hand and save a couple bucks.

ok that's a good tip thanks!