Cheap Chinese Vactrols ...

av500 · Post by **av500** » Mon Sep 21, 2015 3:52 am

... arrived on my desk.

DIP4 VTL5C M1210CLC 5PCS

I have never done anything with Vactrols yet, so it might take a while until I get around to test them properly.

for now I just hooked up my multimeter in resistance mode and used an oldish 3V coin cell to drive the LED for a few seconds.

I measure an OFF resistance well into the 1-10 MOhm range and an ON resistance of 60-100 Ohm, which almost sounds too good to be true to me.

oberkorn · Post by **oberkorn** » Mon Sep 21, 2015 5:09 am

interesting! I might buy a bunch of these just to compare them
to the soon-obsolete Excelitas ones and hear how they sound.

otherwise I'll probably go the 3D-printed route with these: https://www.muffwiggler.com/forum/viewt ... highlight=

skookum · Post by **skookum** » Mon Sep 21, 2015 12:51 pm

This is pertinent to my interests, I have some on order I am expecting soon as well.
The price sure is right on these things.

av500 · Post by **av500** » Tue Sep 22, 2015 1:40 am

hacked together the simplest of low pass gates

signal from my envelope generator through a 10k pot driving the LED. sequencer into square wave VCO to the vactrol and 100n to GND to make a simple RC low pass filter.

playing with the drive strength pot: soundcloud: simple-vactrol-low-pass-gate
http://soundcloud.com/vladimir-pantelic ... -pass-gate

skookum · Post by **skookum** » Tue Sep 22, 2015 11:53 pm

Nice! Any chance of a side-by-side with a "real" VTL5C?

av500 · Post by **av500** » Tue Sep 22, 2015 11:56 pm

skookum wrote:Nice! Any chance of a side-by-side with a "real" VTL5C?

I have one VTL5C4 (which is one if the slower ones according to the datasheet), need to find it.

synchromesh · Post by **synchromesh** » Wed Sep 23, 2015 3:43 am

Thanks av500, I've now ordered a bunch of these (and some other, even cheaper "VTL5C" clones) to go with a big bag of Electric Goldmine vactrols I already have, as well as a selection of Excelitas parts. So my need for a vactrol analyser is now even greater.

The first thing I'll be building from my enormous backlog is a Mutable Instruments module tester, so the easiest thing might be to build some sort of vactrol testing "module" that I can plug into that (possibly with the aid of some alternate firmware).

animalman · Post by **animalman** » Tue Sep 29, 2015 4:30 am

got almost too excited by the link that synchromesh posted. The deal looks like 50 vactrols but further down the description said a "lot of 10"....which the seller confirmed :(

anyway will get a 5 pack to try them out. Thx for the heads up.

Done anymore experiments with them?

synchromesh · Post by **synchromesh** » Tue Sep 29, 2015 3:11 pm

animalman wrote:got almost too excited by the link that synchromesh posted. The deal looks like 50 vactrols but further down the description said a "lot of 10"....which the seller confirmed :(

Hah, at least you read the fine print and verified it, which is more than I managed to do. Still, even a mere 10 vactrols for $10 is worth a punt.

snaper · Post by **snaper** » Tue Sep 29, 2015 11:17 pm

I was planning a 291 (Verbos version) for my Buchla, but gave up the idea after news of the production stop of the VTL line.
Now, there is some light

tarandfeathers · Post by **tarandfeathers** » Thu Oct 01, 2015 10:44 am

I've built 291s successfully using the Silonex optocouplers. It requires a little rejigging of values/connections in the control section to get the ranges right but with that done they work great, I suspect they're probably better than these Chinese ones. The ones I used have a fractionally slower attack than the original Vactec parts, but the decay is about twice as fast. You can still "ping" them with control voltage and get the characteristic Buchla response but the FM range is almost doubled. I posted in the 291 about some changes but when I moved from prototypes to my finished PCBs I made some more adjustments which I'll post when I get a chance...

spacedog · Post by **spacedog** » Fri Oct 09, 2015 9:50 am

these vactrols react to the light of my IKEA 4W LED workbench-lamp (30cm or 1foot away from the vactrol)...
2MOhm to 20MOhm when switching on and off!

ClausF · Post by **ClausF** » Fri Oct 09, 2015 9:53 am

Did you test the same with other Vactrols?

spacedog · Post by **spacedog** » Fri Oct 09, 2015 10:08 am

yes, no problems with Silonex NSL-32 and VTL5C3

sammy123 · Post by **sammy123** » Fri Oct 09, 2015 10:13 am

Damn

Sandrine · Post by **Sandrine** » Fri Oct 09, 2015 10:32 am

It leaks!

I made mine with black heatshrink tubing and they don't leak, wtf?!

Just a thought, last year I built some hardware for a flight simulator, and the throttle quadrant (6 controls) has big handles that were somewhat sloppily welded together. I was going to use slide pots, but they varied too much in position from one to the next.
So I took a cork and inserted an led and a LDR side by side and rammed that into a small blacked PVC pipe. At the other end a dowel with the end painted white was inserted and connected to the big levers.
That way, the led light would bounce off, which measures the distance the dowel is into the tube.

These "pots" might be interesting to use in a module, as a vactrol, but that is adjustable by pulling it out/pushing it in.

J3RK · Post by **J3RK** » Fri Oct 09, 2015 10:47 am

spacedog wrote:

these vactrols react to the light of my IKEA 4W LED workbench-lamp (30cm or 1foot away from the vactrol)...
2MOhm to 20MOhm when switching on and off!

That's strange, but I've seen this before with actual VTLs. It was mostly with a VTL5C9. I checked it for cracks, leaks, defects, nothing. If I put my hand over it, no problem. As soon as it was exposed to light (or maybe heat/infrared?? (though not from an LED I would imagine...)) it would change on me.

I haven't seen this with VTL5C1 or VTL5C3.

I'm wondering if the LDR in the 5C9 was more susceptible to something like this. Any idea what series/model these Chinese ones are meant to emulate?

Edit: I wonder if they aren't sealed well along the leads? Photons are pretty small

What happens if you put a little epoxy around the leads where they meet the case?

spacedog · Post by **spacedog** » Fri Oct 09, 2015 12:58 pm

the cheap "electronic goldmine" vactrols do also not react to light.

av500 · Post by **av500** » Fri Oct 09, 2015 2:26 pm

spacedog wrote:

these vactrols react to the light of my IKEA 4W LED workbench-lamp (30cm or 1foot away from the vactrol)...
2MOhm to 20MOhm when switching on and off!

yes, I found out the same

when I first measured them on the desk they had like 2MOhm, later that day my multimeter showed nothing because it does not go up to 20MOhm. took me a while to realize that the outside light was brighter in the morning

if you look closely, you can see the red LED through the holes where the pins stick out, so it's not "sealed". but a little bit if heat shrink tubing should fix that...

spacedog · Post by **spacedog** » Sat Oct 31, 2015 5:42 pm

I fixed it with black nailpolish.

Off-resistance is now over 200 megaohms.

thetwlo · Post by **thetwlo** » Sat Oct 31, 2015 8:30 pm

spacedog wrote:I fixed it with black nailpolish.

Off-resistance is now over 200 megaohms.

liquid electrical tape may work well.

raph36 · Post by **raph36** » Mon Apr 11, 2016 2:07 pm

anyone tried those ?
LCR0202

http://fr.aliexpress.com/item/Free-ship ... 260.f98E8s

according to the specs it should be a great alternative to their expansive counterparts
1K to 10M dark @10 sec

http://p.globalsources.com/IMAGES/PDT/S ... 105684.pdf

av500 · Post by **av500** » Mon Apr 11, 2016 2:15 pm

raph36 wrote:anyone tried those ?
LCR0202

http://fr.aliexpress.com/item/Free-ship ... 260.f98E8s

according to the specs it should be a great alternative to their expansive counterparts
1K to 10M dark @10 sec

http://p.globalsources.com/IMAGES/PDT/S ... 105684.pdf

no, but I just ordered 10

PWM · Post by **PWM** » Mon Apr 11, 2016 4:39 pm

av500 wrote:no, but I just ordered 10

Excellent! Please report back!

raph36 · Post by **raph36** » Mon Apr 11, 2016 4:53 pm

ordered some too, let's see if we can manage something with those !

MUFF WIGGLER

MUFF WIGGLER

Cheap Chinese Vactrols ...

Cheap Chinese Vactrols ...