Optical compression in the EU

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jensenmann

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Joined
Oct 10, 2004
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2,850
Location
Karlsruhe, Germany
A few VTL5/Cxx vactrols are still available. They seem to be chinese made, not original Vactec. They seem to be made without cadmium, otherwise thy would hve been banned, too. But that itself questions if they are the same part with the same specs than the original vactrols.
 
they seem to be made without cadmium, otherwise thy would hve been banned, too.

No, sadly there is absolutely no ROHS-certifiable LDRs available anywhere. There has been claims of compliance from a couple of manufacturers, both were later found to be fraud (e.g. the Macron products).

As things are right now, any kind of optical compressor is banned from the European market. Yes, that includes UA, Warm and Tubetec...

On the other hand it's very unclear WHY the exemption for the small amounts of cadmium in LDR's for audio was not extended - everyone (including our government ministry of environment) tells me that it's standard policy to extend until a substitute material has been found. The sad thing is that the ban in effect killed the great Excelitas VTLxxx series.

Yes, you can still get (uncertified) Chinese lookalikes, but they are NOT at specs or tolerances anywhere near the Excelitas.

I'm currently designing a provocation named "The Cadmium Beast" or G24, a passive compressor based on a large pile of the Chinese LDR's - the poor tolerances making it necessary to use many many units in series/parallel for matching. The cells will be in a separate module that will only be leased, not sold, and which must be returned to us when we eventually come up with a substitute solution. Which could take a while, according to a material physicist I asked...  /rant 

Jakob E.
 
gyraf said:
As things are right now, any kind of optical compressor is banned from the European market. Yes, that includes UA, Warm and Tubetec...
Add Manley and Avalon and a few more

I always wonder
a) why they are still available everywhere in the EU?
b) why we don't hear any complains from those manufactures or their distributors?
At least those Manufactures using the discontinued VTL Series of Vactrols should know there is a problem?
 
We should make a dedicated thread for this. It is hard. The people from industry whom I discussed this with (more than 20 total) had following three pieces of advice, in order of popularity:

1: Pretend nothing changed. Ignore the problem away.

2: Claim ignorance. Make claim for exemption that you know is wrong, like calling the opto "a high-voltage switch".

3: Lie about it. Who's gonna check anyway...?

In Paris, I talked to a guy from AES's technical committee about this (can't remember his name now) - he was completely unaware of the problem.

..This scares me - and is why I decided to design the CadmiumBeast, to stir up the soup a bit...

Jakob E.
 
You could always inform your local standards body that Harman is possibly importing products that violate ROHS. Should be fun!

Cheers

Ian
 
IIRC you can get away with a % of a  total unit in  existing designs.

So for example, I cannot send  an LDR as a singular part to Europe.... But I can sell you a whole unit with an LDR in it,  or a complete populated circuit board  we use for compressors. 
 
pucho812 said:
IIRC you can get away with a % of a  total unit in  existing designs.

So for example, I cannot send  an LDR as a singular part to Europe.... But I can sell you a whole unit with an LDR in it,  or a complete populated circuit board  we use for compressors.

That would be very handy. Where is this written?

Cheers

IAn
 
But what will they do if that % of a total unit won't be manufactured anymore (due to the ban or not)?

The Market is empty, hard to find a higher quantity of NOS VTLs.
I have seen them in Avalon and Manley gear, do they have such a large NOS stock?

The same question for advices 1 to 3 Jakob described.
 
Ian I wish I knew where it was written,  it is just something I have always been told.

Avalon and others still by ldr's as new not nos, the price had just increased a lot.
 
pucho812 said:
Ian I wish I knew where it was written,  it is just something I have always been told.

Avalon and others still by ldr's as new not nos, the price had just increased a lot.

I just Googled this and basically the requirement appears to be the level of cadmium should be less than 100ppm which is 0.01%. I cannot believe that a more than 0.01% of the mass of a Vactrol is cadmium so there ought not to be a problem. I also discovered that ROHS stands for Restriction of hazardous material not Removal as I first thought.

http://www.rohsguide.com/

Cheers

Ian
 
I find it rather hard to believe that the infamous cadmium light-dependent resistor cell hasn't been fully characterized for its light-vs-resistance function (over several dimensions, immediate response, historical response, whatnot) and duplicated with a $2 ARM microcontroller.

There are surely software plugin compressors that simulate the response. (okay, here's a stupid question) Are they that audibly different compared to a real optical compressor?
 
benb said:
I find it rather hard to believe that the infamous cadmium light-dependent resistor cell hasn't been fully characterized for its light-vs-resistance function (over several dimensions, immediate response, historical response, whatnot) and duplicated with a $2 ARM microcontroller.

There are surely software plugin compressors that simulate the response. (okay, here's a stupid question) Are they that audibly different compared to a real optical compressor?

Modeling that response is required to make an accurate software model of the compressor.
My guess is that modeling the LDR's response as a function of signal level through the resistive part might be tricky.
 
gyraf said:
..........................
On the other hand it's very unclear WHY the exemption for the small amounts of cadmium in LDR's for audio was not extended - everyone (including our government ministry of environment) tells me that it's standard policy to extend until a substitute material has been found. The sad thing is that the ban in effect killed the great Excelitas VTLxxx series.
............................

Because we are being fed with a lot of sh*t from EU regulatory bodies in the name of going green.

Tungsten filament bulb is replaced with electronic bulb. You dispose off a tungsten bulb, all it is a bit of glass, bit of broken tungsten and brass. Compare the electronic bulb against that. Argument goes " ah! but the trick is in energy saving".  Yeah, you saved energy but filled the earth with more and most importantly nasty garbage. And it cost me more money. So, where is the savings?  Recently the maintenance technician of our building asked me for a help to trouble shoot the emergency lighting fittings because the fire master was coming for annual inspection. 12 fittings and all of the electronic ballasts failed in two years.  A quick calculation revealed that any savings that the landlord made from the energy bill was literally a fraction of the cost of the replacement ballasts at £420.00 in total. And, I have not charged my time (as I do a bit of a voluntary work for our heritage centre).

Don't get me wrong. I am probably the greenest guy you could ever see. I recycle pretty much everything. I even keep the off-cut leads from the resistors. I will not waste a screw, But this is insane and nobody is saying anything.

 
There's a lot to this. I'll try to collect my thoughts in this thread.

There is no way around the ban - it's not that industry people didn't try.

It is also possible that professional audio equipment is in category 11

No, it's not, sadly. We already had an exemption specifically for audio which expired, which means that we can't claim to be covered by some other exemption.

Inventory 40 in this list was our exemption: http://www.tuv.com/media/usa/standards_update_1/EU_RoHS_Exemptions_Update_ENTRNA.pdf

and

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:348:0018:0019:EN:pDF

To quote elfa:
This was exemption 40 of the RoHS Directive “Cadmium in photoresistors for analogue optocouplers applied in professional audio equipment”. This expired on 31 December 2013 so it can be no longer be used and there is no replacement exemption. There are no drop-in replacements available.


ruffrecords said:
That would be very handy. Where is this written?

http://www.rohsguide.com/  - limit of 100ppm (0.1%).

By itself the 0.1% limit demand for Cadmium would be easy to do, as the absolute content of Cd is in the order of 100ug (0.0001g) per LDR cell (in one of the proceedings of the ROHS committee it is mentioned that the entire pro audio market is using in the range of grams per year).

The problem is in the detail of how to measure - the ROHS explicitly specifies measurement in "mechanically separable parts" - meaning any way you could take it apart with a sharp knife or the like. And now we are up around 1-1½% Cd in the stuff that can be scraped off under the clear coating, between the terminals. No manufacturer has succeeded in coming around this.

Of alternative materials, Lead sulphide (PbS), Indium antimonide (InSb) and GeCu are often mentioned, all infrared sensitive.

Problem persists though: PbS is banned too under ROHS, and not a single manufacturer currently produces InSb or GeCu photoconductive cells afaik.

Last, there was actually some commercial companies opposing the recently-expired exemption for audio use - arguments including e.g. "optical compressors could as well be simulated in DSP" (yes, really!!) and "Our company has manufactured a substitute material that is ROHS certified" (which turned out to be fraud!)

Jakob E.
 
Mmmmmmmmm. Depressing.

Wouldn't it be nice if, post Brexit, the UK dropped such silly ROHS requirements and the only place you could get opto compression would be in UK studios leading to a massive revival in the UK recording industry.

Ah well, you can't blame an old guy for dreaming.

Cheers

Ian
 

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