LDR's Rohs and Alternatives

[guitarmike2107]

Does anybody know if LDR are still RoHS compliant by exemption? or should I just try use something else for channel switching. I don’t really want to use relays


Also, I only need two shunt switches, So if I used LDR or relays is it ok to switch LDR's directly off a power supply through a 3 metre foot switch.

Thanks

Michael

[Enzo]

Find a vendor who sells the LDR you are thinking of, and look up the data sheet on it. And if the data sheet doesn't tell you that, then contact the vendor and ask if the part is RoHS compliant, for whatever reason. They sell the part into the market, they HAVE to know this.

[guitarmike2107]

Thanks Enzo , thats a good idea.

RS Sells the VTL5C1 but it is marked as non compliant, however I was of the understanding that you could not sell non compliant products in the EU?
I will e-mail them to ask

The ones I can get from Digikey are just the photosensor parts, So I would have to DIY them with an LED. Not a big hassle really.

[guitarmike2107]

It appears that they were exempt and no longer are.

this Rohs page has parts listed that have lapsed.

http://www.rohs.gov.uk/Docs/Deleted%...009%202010.pdf

[guitarmike2107]

ok just to follow this up a bit more. (and I do enjoy a chat with myself)

it appears that macron manufacture Rohs Compliant LDR's, they actually requested that the Rohs exemption be removed, as they were compliant as tested by two testing houses. Just need to find out who sells them.

[guitarmike2107]

ok last one I promise

There is some debate about macrons claim, so I guess its relays or something else till the exemption is granted again or somebody comes up with a new product that really is Rohs complaint

[Steve Conner]

Fender replaced the "trem bug" in their reissue amps with a whole PCB full of gubbins. I believe it was for this very reason.

LDRs are made of cadmium sulphide, which is banned because it contains cadmium. I don't know of any good alternative.

Some people have had good results with solid-state relays. The normal kind with a triac output are useless, but you get little ones with MOSFET outputs that can switch AC or DC. There's discussion of this on the forum, try searching.

[Robert M. Martinelli]

When it comes to use SSRs in audio application, not only the RDS(on) has to be as low as possible, but the RDS(on) should be as CONSTANT as possible with respect to all frequencies passing through, otherwise the insertion of the SSR would risk to alter the response within the range of frequencies of interest.

Time ago I tried the MAX4601 (4NO) MAX 4602 (4NC) MAX4603 (2NC+2NO) series, (I used a MAX4603 on a SS FX design). According to the manufacturer, they can switch voltages (signals) up to 80 V, and their RDS(on) is guaranteed to be as low as 2,5 Ohms on all the audio spectrum. It behaved very well IMHO, now, I would like to try to use them to switch channels in a tube preamp...though I suspect I'll have to wait for my retirement to do so....

Cheers

Bob

[guitarmike2107]

I have looked at the solid state relays but they seem to have a minimum load current requirement, the way I plan to use them they have no load current.

With respect to the LDR's is has Mesa changed to another method in the new dual rectifier?.... I wonder what Morley are doing in the pedals too.

[Steve Conner]

You're looking at the wrong ones. If there's a minimum load current, they're triac output. Here is an example of the kind I mean, from Avago (ex HP) Data Sheet - ASSR-401C and ASSR-402C Low C x R, Form A, Solid State Relay (Photo MOSFET) (400V/100

£2.90 from Farnell.

RoHS is only for the EU. Maybe Mesa get away with it by buying and manufacturing in the USA.

[guitarmike2107]

Thanks Steve, those look perfect.. I better go build this amp now

[jpfamps]

RS Sells the VTL5C1 but it is marked as non compliant, however I was of the understanding that you could not sell non compliant products in the EU?
I will e-mail them to ask

You are allowed to sell non-RoHS compliant components; you aren't allowed to use these in new products, but can use them for repairs.

[R.G.]

You are allowed to sell non-RoHS compliant components; you aren't allowed to use these in new products, but can use them for repairs.

I'm sure the governments will protect us from that any time now.

[jpfamps]

I'm sure the governments will protect us from that any time now.

Indeed.

Although as military equipment is still exempt from RoHS I expect that there will need to be a supply of leaded solder to repair it!

[d95err]

AFAIK it is forbidden to repair equipment built with leaded solder using lead-free, and vice versa. So, as long as there are still a few vintage amps still running, leaded solder will be available.