LA-2A LDR exemption has ended

Don't know if anyone else has picked this up, but Exemption 40 of the RoHS Directive came to an end on 31st Dec 2013.

This was "Cadmium in photo-resistors for analogue opto-couplers applied in professional audio equipment".

Although I have made a very nice LA-2 using green LED's, that is no help as they still have to have the photo-resistors to pick up the light.  Maybe it might be possible to construct some kind of SS alternative, but I would not know where to start myself.  Maybe a phototransistor  circuit would be ok for the meter control, but the main control resistor is across a grid.

Hmmm, food for thought
DaveP

well...balls.

Only a few of the range of avaialble photo resistor based optos use cadmium sulphide. There are plenty of others that use different photo-resistive materials that have not been banned. Unfortunately, they do not have the same attack/decay characteristics as the Cadmium sulphide ones.

Cheers

Ian

PbS is banned too...

Service does not fall under RoHS if the unit was into market prior to the sunset date, perhaps there's a way around to 'service' the units? 

This also may be an indicator that technology has caught up to justify doing away with the exemption, any news on new tech?

tons of old school LDR's on evilbay, trick is to know which ones to buy,


http://www.ebay.com/sch/i.html?_odkw=silicone+LDR&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR11.TRC1.A0.H0.XLDR&_nkw=LDR&_sacat=0

Radio Shack used to sell a variety pack which had a pair of really nice sounding LDR's,

i think they still sell them but not the variety pack,

motion detectors have LDR's in them, some good, some not,

EL panels? used to be able to pull them out of alarm clocks until blue LED's came along, this eliminated the HV switcher and thus dropped the parts count down dramatically so now were back to LSI,

The response curves on LDR's is pretty easy to test (at least to compare candidates). Just hook up a resistor and LDR with a voltage, and put an Oscilloscope probe across it.  Then set a bright light above it, and take a vent panel from some enclosure (with a row of strips cut out of it for ventilation).

Hold and move the panel between the light and the LDR in a relatively dark room, and you get a nice oscilloscope trace that characterizes the LDR.

Some are very fast responding to light, some are slower.  The other major difference is how long it takes them to regain their "dark adjusted" state.  I bought an assortment of LDR's once and classified them that way.

I am sure you could have some sort of mechanical way of making the flashing (disk with a slot on a drill?) but it is not really needed. I found I could determine which were fast and which were slow pretty easily, so I could decide which of my stock to use for the compressor (the faster ones).

you can also just install the T4b in the compressor and use the VU meter to see what kind of cells you have,

that way you do not need a test fixture and scope,

plug in a mic and watch the needle decay when it compresses,

usually an 8 second return time will get you in the ball park,

most of the material 5 cells from Silonex have about the same on time (very quick) but vary on the decay curve,

you can also just listen to the cells, if they are too quick, they can sound harsh,

if too slow then you get a volume swelling effect,

testing helps get the VU meter to track the compressing cell,

does not have to be perfect, you can dial in an LA2a with your ears, no meter required, these cell compressors are not very precise as the cells are not very precise, compression depends on earlier events, etc

> Service does not fall under RoHS if the unit was into market prior to the sunset date, perhaps there's a way around to 'service' the units?

The service replacement market is roughly zero. Light controllers can be done with photo transistors. The honest replacement market for LA2a is a dozen a year; UREI quit supplying them it wasn't worth it. Nobody is going to keep a "toxic part" production line going for this kind of market.

> This also may be an indicator that technology has caught up to justify doing away with the exemption, any news on new tech?

JETs, VCAs, etc do "the same job" with a few more perfectly-legal parts.

My state worry-warts will pay me _$5_ for a Mercury thermostat. They just want the merc recovered before it ends up in our drinking wells. Now I know why I have been hoarding old thermostats. (Wonder what they'd pay for a big Mercury rectifier?)

PRR - If you mean a vacuum tube rectifier, probably not much.  A Mercury tilt switch has a lot more quicksilver than an 866. 

i have some hi-freq PCB ballast coils for sale if anybody wants them,

takes away headaches from pulsating fluorescent lights,

makes those non-productive cubicle workers even more happy,

CJ said:

tons of old school LDR's on evilbay, trick is to know which ones to buy,
http://www.ebay.com/sch/i.html?_odkw=silicone+LDR&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR11.TRC1.A0.H0.XLDR&_nkw=LDR&_sacat=0

Click to expand...

Does anyone know which, if any, of those 6500, are good ones? 

EL panels? used to be able to pull them out of alarm clocks until blue LED's came along, this eliminated the HV switcher and thus dropped the parts count down dramatically so now were back to LSI,

Click to expand...

I was looking at EL panels on ebay the other day, they have some that can be cut to size.. they sell inverters for them, to make 150VAC from 12VDC, so I guess 100VAC or more will light them up ok?  What kind of voltage does the LA2 send to the EL panel?  Will these "work"?

http://www.ebay.com/itm/EL-Lamp-electroluminescent-panel-backlight-led-alternative-no-lead-/331137169394?pt=LH_DefaultDomain_0&hash=item4d195037f2

mjrippe said:

PRR - If you mean a vacuum tube rectifier, probably not much.  A Mercury tilt switch has a lot more quicksilver than an 866. 

Click to expand...

I bet he means a mercury vapor or arc rectifier from a 50kW transmitter.  Now there's a party. 

Few years ago I catalogued one of the oldest electrically driven cranes in the world  in one of the docks that was being flattened. The jib motor was driven by a DC motor (for reversing easier). The sub station had 3 phase rectification with mercury arc rectifiers, I think 200A each. These were around 80cm in diameter and 1m high. Cooled by big fans placed under side.

P.S. It is also called Hewittic Rectifier.

https://www.youtube.com/watch?v=QY6V2syGnZA

Holy Crap!  I stand corrected, that is an amazing tube full of toxic liquid metal.  Photonicinduction always has the best YouTube vids...

> What kind of voltage does the LA2 send to the EL panel? 

Look at it. There is, what? 300 Volts supply? If you don't care about distortion, and the load is light, a fat pentode can swing much of the supply as peak-to-peak "sine" wave. So much of 300V divided by 2.8 is about 100V "RMS".

And we don't know that the opto-attenuator needs to be as bright as the light in the bathroom. LDRs drop with quite dim light, and here they work against a modestly high resistor value (47K? 27K?).

I think the EL chemistry has been settled since our first EL piss-light in 1966. Probably doesn't matter who made it or when.

866, bah, toy.

Thanks PRR.  So they may work, I guess? Will have to order one and see what happens.  That and a variety of those chinese LDRs...

cheers!

mjrippe said:

Holy Crap!  I stand corrected, that is an amazing tube full of toxic liquid metal.  Photonicinduction always has the best YouTube vids...

Click to expand...

nice fake bloody hand:

https://www.youtube.com/watch?v=6Oq9VC94vbw

"electric" guitar>

https://www.youtube.com/watch?v=TwIvUbOhcKE