Well I bit it this time, I decided to buy cheap Xvive vactrols from China and save a few bucks. How wrong I was, they didn't work and it ended up costing more in the end after I had to order proper ones from small bear. I really should have known better, installing the chinese 'Xvive' in both the deadendfx turbo trem and E nigma made them partially work, the turbo trem only worked for certain wave shape settings and the time portion of the E nigma wouldn't flange properly. So to save others the self induced grief caused from being a tight wad you should avoid the following vactrols on Ebay;
https://www.ebay.ca/itm/5pcs-VTL5C3-Xvive-Audio-Opto-Coupler/392257148367?hash=item5b545915cf:g:Y0AAAOSwzMlchhaS
I tried these out in other projects I have that use opto's but they also do weird stuff, so I'd say they're complete duds. Lesson learned :icon_redface:
Yikes!
Here's what a genuine Xvive Vactrol looks like:
https://electricdruid.net/product/xvive-vtl5c3-vactrol/
BTW, Xvive is a brand of a Chinese company (Shenzhen FZone Technology Co.Ltd.), so the genuine ones come from China too. Interesting that the Chinese fakers are ripping off Chinese businesses as much as everyone else.
T.
In recent months (years?), I've bought a lots of different vactrols from different sources. Finally, I decided to make a vactrol tester and see what I really have at hand. Basically, I wanted to test rise/fall times, because resistance can be easily measured. So I came to this:
(https://i.postimg.cc/876CZRpy/vactrol-tester.jpg) (https://postimg.cc/876CZRpy)
Simple 555 based astable multivibrator, with 1s period and short trigger pulse, so vactrol is hit with a short pulse, and then left to fall.
Those are oscillographs for the first three I tested:
#1 is Xvive VTL5C2 (green dot), bought from www.musikding.de
(https://i.postimg.cc/648KyKTH/VTL5-C2-Xvive.png) (https://postimg.cc/648KyKTH)
#2 is VTL5C2 1710 PRC (original?) I bougth recently from Aliexpress:
(https://i.postimg.cc/N5rYtQ3F/VTL5-C2-PRC.png) (https://postimg.cc/N5rYtQ3F)
#3 is VTL ST, bought from Aliexpress, I have 30 of them and they were insanely cheap (and sold as VTL5C1, if I remember well)
(https://i.postimg.cc/PLKnyJw3/VTL-ST.png) (https://postimg.cc/PLKnyJw3)
It seems that #1 is actually very far from real VTL5C2 specs (if we look fall times), because it is very short. On the contrary, both Chinese VTLs look much closer to required fall time (500ms). I will test more soon and post my findings here. Off resistance on all three of them is more than 200M, so I couldn't measure it.
OK, after them, #4 tested is LCR-0202 (https://www.senbasensor.com/products/low-distortion-coupling-linear-optocoupler.html). It can be bought for cheap and is in a cute and small rectangular case.
(https://i.postimg.cc/WFSbjmXm/LCR-0202.png) (https://postimg.cc/WFSbjmXm)
Seems to have slow fall time as well. Off resistance is still too big to measure.
#5 is VTL5C3 1440 PRC (presumably original?) bought from Banzai Music:
(https://i.postimg.cc/gLJc0wTC/VTL5C3.png) (https://postimg.cc/gLJc0wTC)
#6 is VTL5C3 Xvive (yellowish dot) bought from Banzai Music, too:
(https://i.postimg.cc/HjZsh2Jd/VTL5-C3-Xvive.png) (https://postimg.cc/HjZsh2Jd)
Notice the difference between the two!
#7 is VTL5C10 1423 PRC bought from uk-electronic.de
(https://i.postimg.cc/BjDStfmn/VTL5C10.png) (https://postimg.cc/BjDStfmn)
#8 is NSL-32 bought from Banzai Music
(https://i.postimg.cc/67X9vbPL/NSL-32.png) (https://postimg.cc/67X9vbPL)
And that's all from my collection. I do have one VTL5C9 (original), but it's already soldered to the Weak Joe compressor and I'm not in the mood to desolder it just to check it's fall time :)
Soon I will measure resistances at 1mA and 10mA LED current.
Photos of all tested vactrols for your reference:
(https://i.postimg.cc/tsRk49qh/vaktroli.jpg) (https://postimg.cc/tsRk49qh)
Judging only by those fall times, VTL5C3 Xvive is very similar to LCR-0202 and VTL5C2 1710 PRC.
VTL5C3 1440 PRC (from Banzai) is very similar to NSL-32 and VTL ST is similar to them, but with slightly different resistance. I presume fall time for all those six fellas is 500ms, although VTL5C3 should have 35ms fall time.
VTL5C2 Xvive from Musicding is totally different from all the others, regarding both resistance and fall time, which is approx. 30-50ms (should be 500ms acc. to datasheet).
VTL5C10 1423 PRC seems to be original, see slow fall ramp (1.5s acc. to datasheet).
Quality components that are up to spec have everything to do with the seller, NOT the country of origin. If you don't trust the seller, don't buy regardless of where the manufacturer has underage slave wage labor toiling away for your convenience. If you trust the seller, Chinese components used in audio devices will be every bit as good as those made in Japan or Germany or the US. It's the owner/management of the company that is ultimately responsible for quality. Are there fake ______? Probably, but your chances of getting those as opposed to simply out-of-spec components are near zero. Selling fakes on eBay doesn't make anyone any significant money at all and most people aren't thieves anyway. Lazy redistributors of out-of-spec, passé technology? Sure. Thieves who spend time and effort making fake components to trick the random drop in the bucket DIYer who spends 10, 20 bucks a pop? No.
Conclusion:
(https://i.postimg.cc/1V63NgS4/tabela.jpg) (https://postimg.cc/1V63NgS4)
I couldn't precisely measure fall time (from resistance @ 1mA to 100k) and I actually calculated this time from oscilloscope screenshots, which are very low res. But this table shows that most of these vactrols are really not so close to original Perkin Elmer / Excelitas specs. On the other side, it seems that there are some really cheap ones (LCR-0202 and VTL ST), which can be easily used in various circuits with little (if any) alterations instead of VTL5C2/4/10, for example.
If one has an idea how to precisely measure fall times, please help.
I love using vactrols in stuff and will sometimes socket and even try different ones from the same batch to see what happens. But I wanted to recommend roll-your-own's for the Loveclone projects, Deadendfx or otherwise. I can't recall the exact specs recommended in the DEFX Meaty Balls build doc or Alanp's Meatball but after building Meatballs using both vactrols and my own green LED home made ones (including in a build of the musicpcb.com one) I will probably not go back to vactrols for any Lovetone build. I had an original meatball in the 1990s and only the rolled-my-own version comes close sonically.
(I have Turbotrem on the bench right now and Alanp's version of the ? flanger, and will probably make my own led/ldr combos for those too, we'll see.) It is certainly cheaper but extra legwork, but fun ---
Roll your own! :)
Quote from: Strategy on December 30, 2019, 12:33:23 AM
I love using vactrols in stuff and will sometimes socket and even try different ones from the same batch to see what happens. But I wanted to recommend roll-your-own's for the Loveclone projects, Deadendfx or otherwise.
What kind of photoresistors do you use for that?
QuoteWhat kind of photoresistors do you use for that?
I used 10k/1M LDRs and diffuse green LED's.
Cool experiment, Rankot. Thanks for sharing!
What would be a good recommendation to roll ones own VTL5C4/2 for a DOD 440 Envelope Filter clone?
I tried an XVIVE one from SmallBear. It filters, but crackles a lot. It appears to be the Vactrol as the crackle disappears when removed but I am not sure of the circuit either, so the Vactrol may be ok. I would like a test, but those Vactrols are pricey for just testing. This would be a 5pin Vactrol.
Quote from: Strategy on December 30, 2019, 12:12:56 PM
I used 10k/1M LDRs and diffuse green LED's.
Any specific type, or just some no names?
QuoteIt filters, but crackles a lot.
That's probably not crackling, like what's going on in a faulty cable, but a phenomenon known as ripple. It's the bane of every amplitude envelope follower design. I seriously doubt there is anything "wrong" with your vactrols that's producing that sound. Instead of retread a well worn path here, let me just throw a couple links to further reading below.
http://www.geofex.com/article_folders/ecftech/ecftech.htm (http://www.geofex.com/article_folders/ecftech/ecftech.htm)
https://www.nicolascollins.com/texts/electronotes.pdf (https://www.nicolascollins.com/texts/electronotes.pdf)
https://m.eet.com/media/1141271/18042-122602di.pdf (https://m.eet.com/media/1141271/18042-122602di.pdf)
https://www.diystompboxes.com/smfforum/index.php?topic=37679.0 (https://www.diystompboxes.com/smfforum/index.php?topic=37679.0)
Quote from: garcho on December 31, 2019, 09:57:37 AM
That's probably not crackling, like what's going on in a faulty cable, but a phenomenon known as ripple. It's the bane of every amplitude envelope follower design. I seriously doubt there is anything "wrong" with your vactrols that's producing that sound. Instead of retread a well worn path here, let me just throw a couple links to further reading below.
http://www.geofex.com/article_folders/ecftech/ecftech.htm (http://www.geofex.com/article_folders/ecftech/ecftech.htm)
It says: "Audible effects of ripple are also most likely to occur if the control element is of the type that can respond very fast. Photocell-based ECF's are relatively immune from audible ripple, simply because photocells don't return from their MAX/ON to MIN/OFF value very fast, and impose a longer decay period without additional circuitry. The same envelope follower circuit used with a transistor as the control element may well result in considerable audible ripple unless the decay period is deliberately smoothed out with additional circuitry or larger value capacitors. The pros and cons of control elements are described in more detail in a section below."
So maybe his choice of LDR is important, if fall time is very small, it will produce ripple (if that is what bothers him)?
But also, maybe resistance range of LDR used is not proper, so op amp is clipping sometimes?
Also here's more reading on envelope ripple.
https://www.diystompboxes.com/smfforum/index.php?topic=114323.msg1060987#msg1060987
It can be challenging. A quick forum search for envelope ripple will reward you with more knowledge.
Quote from: rankot on December 30, 2019, 04:57:13 PM
Quote from: Strategy on December 30, 2019, 12:12:56 PM
I used 10k/1M LDRs and diffuse green LED's.
Any specific type, or just some no names?
I just used whatever I could get my hands on, but I didn't mix parts from different sources/batches
I didn't measure for matching or anything.
- Strategy
Is this the ripple that you folks speak of?
This is what is happening with my XVive VTL5C4/2 vactrol. If that is the case, how do I fix that? Get another vactrol? Roll my own? If roll my own, what LEDs and LDRs and where do I get them?
And if you adjust the level pot?
http://beavisaudio.com/schematics/DOD-440-Envelope-Filter-Schematic.htm
Here's the pot adjustments:
I was basing this on the schematic of GGG:
http://www.generalguitargadgets.com/effects-projects/filters-envelope/dod-440-ef/ (http://www.generalguitargadgets.com/effects-projects/filters-envelope/dod-440-ef/)
I've discovered the Beavis Audio schematic appears to have errors. Different Vactrol type, for that matter.
If I pull the Vactrol out, all that extra noise goes away, so it doesn't appear to be a bad solder job or bad components otherwise. I did leave sockets for where the vactrol's 5 leads went so if I ever got another or figured out how to roll my own, I'd have something to compare it to.
Check C3/C4 capacitor values, as well as values of C2, R4, R5 and R6. Check if your D1 or D2 is soldered backwards, for example.
So, no problems detected on values or orientations.
QuoteCheck C3/C4 capacitor values
C3, the bias decoupler electrolytic capacitor, is 10uF and is soldered on with the proper polarities in mind.
C4, the op amp DC decoupler electrolytic capacitor, is 4.7uF and is soldered on with the proper polarities in mind.
Quoteas well as values of C2, R4, R5 and R6
C2, the input box film capacitor, is 10nF and its solder job has proper continuity.
R4 is a 10K resistor and is soldered into the correct position.
R5 and R6 are 100K resistors and are soldered into the correct position
QuoteCheck if your D1 or D2 is soldered backwards
D1 and D2 are 1N4148 diodes and are soldered on with cathode and anode position in mind, correctly.
Keep in mind the Beavis Audio schematic is incorrect, primarily due to their vactrol. A 4 pin VTL5C9 wired that way cannot envelope filter (as pedalpcb found out the hard way when copying it and releasing their version of it). It requires a 5 pin style VTL5C4/2 (as pedalpcb later figured out and GGG already knew)
Regarding DOD440, there some info here: https://www.diystompboxes.com/smfforum/index.php?topic=98638.0 (https://www.diystompboxes.com/smfforum/index.php?topic=98638.0), here https://www.diystompboxes.com/smfforum/index.php?topic=112323.0 (https://www.diystompboxes.com/smfforum/index.php?topic=112323.0) or here http://guitar-fx-layouts.42897.x6.nabble.com/DOD-440-td3168.html (http://guitar-fx-layouts.42897.x6.nabble.com/DOD-440-td3168.html)
Checked that. No go. I'll break this off into a new post.
Quote from: bushidov on January 04, 2020, 05:59:21 AM
Checked that. No go. I'll break this off into a new post.
OK. In case you decide to make your own vactrol, here is the datasheet for VTL5C4/2:
(https://i.postimg.cc/MvbBxNN2/VTL5c4-2.jpg) (https://postimg.cc/MvbBxNN2)
You need two matched LDRs for that. You may try with GL5516, for example, they seem to have similar characteristic to VTL5C4/2, but you also need to find a good LED for the purpose. Have in mind that different LED's produce different amount of light with the same current, so you must experiment to match datasheet specs. If you use those LDRs, pick green LED. But what can be the problem here is the fact that most of similar LDRs have fall time in 30-50ms range, while VTL5C4/2 has fall time of 1.5 seconds! Thus, you may need some more ripple filtering before LED, because such a slow fall time make unnecessary to filter envelope before the LED, and short fall times require that. Unfortunately, I'm not aware of LDRs with such a long fall times.
Here is a hypothetical and possibly stupid question on my part: only for the sake of testing, could I rig a dual gang pot (Or regular pot) to emulate the vactrol? I mean, I can spin a pot back and forth within 1.5 seconds, if nothing more than to just test.
Of course you can. 8)
Quote from: bushidov on January 04, 2020, 07:35:47 AM
Here is a hypothetical and possibly stupid question on my part: only for the sake of testing, could I rig a dual gang pot (Or regular pot) to emulate the vactrol? I mean, I can spin a pot back and forth within 1.5 seconds, if nothing more than to just test.
if you have a pair of same type ldr's, you can tack solder them in as a dual, then just wave your hand over them, with a stong light above. you should hear some sweep. if you can lash it up on a breadboard and cover the ldr's and a led, you can get a better bit of sweep action. if you just want to test the rest of the circuit operation, that is.
Thanks Duck_Arse and Rankot, I'll give it a try. I created a new post for this issue as to not be tacked onto the original poster's question.
Quote from: Giveusyourbones on September 25, 2019, 01:47:30 PM
So to save others the self induced grief caused from being a tight wad you should avoid the following vactrols on Ebay;
https://www.ebay.ca/itm/5pcs-VTL5C3-Xvive-Audio-Opto-Coupler/392257148367?hash=item5b545915cf:g:Y0AAAOSwzMlchhaS
I bought one of these fake XVive vactrols, the fake measures 25M dark resistance where a VTL5C3 is 10M, I complained and got an instant refund no return needed so I took it apart and found a cheap red LED where a VTL5C3 has a standard green one. The fake one probably works ok for some applications but not typical audio. It actually worked better when I stuck a green LED but the resistance is still wrong if you need a VTL5C3...
Quote from: ficelles on June 02, 2020, 03:31:37 PM
I bought one of these fake XVive vactrols, the fake measures 25M dark resistance where a VTL5C3 is 10M, I complained and got an instant refund no return needed so I took it apart and found a cheap red LED where a VTL5C3 has a standard green one. The fake one probably works ok for some applications but not typical audio. It actually worked better when I stuck a green LED but the resistance is still wrong if you need a VTL5C3...
Dark resistance is not actually too important in most uses! What IS important is bright resistance, as well as rise and decay times. That is because in most times LDR is used in parallel with another resistor, so if it is not lit, another one takes precedance.
Quote from: rankot on June 02, 2020, 04:31:42 PM
Dark resistance is not actually too important in most uses! What IS important is bright resistance, as well as rise and decay times. That is because in most times LDR is used in parallel with another resistor, so if it is not lit, another one takes precedance.
Tricky to measure light resistance though, or is there an easy way to do it?
I like the VTL5C9 which run about $9 ouch! I got some XVive substitutes from AliExpress for about $1 each. I bought 15 and tested one at random and it worked fine. By ear it seemed to have the same qualities as the VTL5C9.
I didn't test all of the 15. I did notice the quality wasn't quite as good. Some of the LEDs were loose in the enclosure. This shouldn't affect performance.
Quote from: ficelles on June 21, 2020, 04:30:51 PMTricky to measure light resistance though, or is there an easy way to do it?
Light. Ohm meter. What is tricky?
I find dark resistance trickier. Response extends to VERY DARK. Far too dark to read the meter. I've rigged baffles and remote meter. Fortunately I never need "true dark". In fact if it goes over 100k that's normally great.
Quote from: soggybag on June 21, 2020, 05:18:03 PM
I like the VTL5C9 which run about $9 ouch! I got some XVive substitutes from AliExpress for about $1 each. I bought 15 and tested one at random and it worked fine. By ear it seemed to have the same qualities as the VTL5C9.
I didn't test all of the 15. I did notice the quality wasn't quite as good. Some of the LEDs were loose in the enclosure. This shouldn't affect performance.
Care to share a link to those?
Here is what I bought, cheaper than I remembered $3.70 for 5 plush shipping. I paid $16.41 for 15 shipped.
https://www.aliexpress.com/item/4000258174075.html?spm=a2g0s.9042311.0.0.30974c4dxj9IfC
Quote from: soggybag on June 21, 2020, 11:56:05 PM
Here is what I bought, cheaper than I remembered $3.70 for 5 plush shipping. I paid $16.41 for 15 shipped.
https://www.aliexpress.com/item/4000258174075.html?spm=a2g0s.9042311.0.0.30974c4dxj9IfC
I see, but shipping to my country is 90 USD... :icon_eek:
I have a few of similar marked optos, maybe they're the same? Will check.
In the meantime, there are datasheets for Xvive products: http://www.xviveaudio.com/art/download-a0044.html (http://www.xviveaudio.com/art/download-a0044.html)
Quote from: rankot on June 22, 2020, 05:31:58 AM
Quote from: soggybag on June 21, 2020, 11:56:05 PM
Here is what I bought, cheaper than I remembered $3.70 for 5 plush shipping. I paid $16.41 for 15 shipped.
https://www.aliexpress.com/item/4000258174075.html?spm=a2g0s.9042311.0.0.30974c4dxj9IfC
I see, but shipping to my country is 90 USD... :icon_eek:
I have a few of similar marked optos, maybe they're the same? Will check.
In the meantime, there are datasheets for Xvive products: http://www.xviveaudio.com/art/download-a0044.html (http://www.xviveaudio.com/art/download-a0044.html)
I'm not sure where you're seeing $90 shipping. I paid $16 for 3 packs of 5. When I tap shipping I see AliExpress shipping $3.05, EMS $40.17 and DHL $40.28. I obviously chose the first option. There's no way I'd pay $40 shipping for $10 of parts.
Quote from: soggybag on June 22, 2020, 11:28:11 AM
Quote from: rankot on June 22, 2020, 05:31:58 AM
Quote from: soggybag on June 21, 2020, 11:56:05 PM
Here is what I bought, cheaper than I remembered $3.70 for 5 plush shipping. I paid $16.41 for 15 shipped.
https://www.aliexpress.com/item/4000258174075.html?spm=a2g0s.9042311.0.0.30974c4dxj9IfC
I see, but shipping to my country is 90 USD... :icon_eek:
I have a few of similar marked optos, maybe they're the same? Will check.
In the meantime, there are datasheets for Xvive products: http://www.xviveaudio.com/art/download-a0044.html (http://www.xviveaudio.com/art/download-a0044.html)
I'm not sure where you're seeing $90 shipping. I paid $16 for 3 packs of 5. When I tap shipping I see AliExpress shipping $3.05, EMS $40.17 and DHL $40.28. I obviously chose the first option. There's no way I'd pay $40 shipping for $10 of parts.
For my country, there's only one option for shipping, DHL and it costs USD 90... Before this COVID outbreak, shipping was possible using regular post and was dirt cheap, but it seems there's no more now.
Quote from: rankot on June 22, 2020, 12:13:23 PM
Quote from: soggybag on June 22, 2020, 11:28:11 AM
Quote from: rankot on June 22, 2020, 05:31:58 AM
Quote from: soggybag on June 21, 2020, 11:56:05 PM
Here is what I bought, cheaper than I remembered $3.70 for 5 plush shipping. I paid $16.41 for 15 shipped.
https://www.aliexpress.com/item/4000258174075.html?spm=a2g0s.9042311.0.0.30974c4dxj9IfC
I see, but shipping to my country is 90 USD... :icon_eek:
I have a few of similar marked optos, maybe they're the same? Will check.
In the meantime, there are datasheets for Xvive products: http://www.xviveaudio.com/art/download-a0044.html (http://www.xviveaudio.com/art/download-a0044.html)
I'm not sure where you're seeing $90 shipping. I paid $16 for 3 packs of 5. When I tap shipping I see AliExpress shipping $3.05, EMS $40.17 and DHL $40.28. I obviously chose the first option. There's no way I'd pay $40 shipping for $10 of parts.
For my country, there's only one option for shipping, DHL and it costs USD 90... Before this COVID outbreak, shipping was possible using regular post and was dirt cheap, but it seems there's no more now.
Sorry, I didn't realize you were not in the US.