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.

[R.G.]

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.

Frankly, it's not all that hard to melt tin in a steel pot and add in the right amount of lead. Well, until all lead is made illegal, at least. 8-)

The USA at least has no RoHS laws, so it's still legal here.

Remember, when solder is outlawed, only outlaws will have solder... 8-)

[jpfamps]

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.

Although it's not a good idea, I can't believe it is illegal to repair equipment built with leaded solder with lead-free solder!

Regarding the converse situation, I'm not 100% sure whether you are obliged to use lead-free solder and RoHS compliant components.

At the risk of alerting the lead police to my activities, I use leaded solder in all repairs. In fact about the only way I've found to extract lead-free solder from plated through holes on a PCB has been to apply leaded solder to the joint first (and someone I know who has been repair gear alot longer than me uses the same technique).

The logic I apply here is that by repair something I will avoid it ending in land fill.

I suspect the continued availability of leaded solder in the UK isn't becuase of the huge demand to the vinatge valve amp repair market.

[octal]

Not to state the obvious, but a piece of "lead free" electronics gear that's had a few crusty connections retouched with leaded solder is still going to contain a tiny fraction of the lead it otherwise would if the entire PCB was wave soldered with leaded solder. The issue certainly wouldn't keep me up at night. There's also not any sort of compliance inspection for 5-10 year old electronics gear. I suppose that in warranty repairs performed in an EU country could be different story though, but I doubt there's the resources to enforce that.

Nathan

[guitarmike2107]

Maybe we should stockpile lead solder and in 40 years time when its is no longer available we can sell it at “NOS” inflated prices.

I haven’t tried lead free solder yet, but I probably will do so shortly.. is it really that bad?

[Steve Conner]

Well, I don't like it either, it doesn't seem to flow as well as the old leaded stuff when hand soldering, even at a higher temperature.

I have a stash of leaded solder, and when that runs out I'll worry about the lead-free stuff.

[jpfamps]

The main problem I initially found with most non-leaded solder (other than the poor flowing and higher melting temperature) is that virtually every joint looks like a dry joint.

If you really have to use lead-free solder, then the only solder I've used that gives decent results is the silver loaded, which is obviously more expensive. Also you need a decent soldering iron.

The best lead-free solder I've found in the UK is the Rapid Electronics own brand tin solder with 4% Ag, 0.5% Cu.

This flows much better than any of the other lead-free solder I've used, even solder with apparently the same formulation, and you can use it with a No.7 Weller Magnastat tip (370 degC), whereas with other lead-free solder I've had to use a No.8 tip (415 degC).

In fact when building some amps a couple of weeks ago using this solder I almost convinced myself that it was as nice to use as leaded solder. That was of course until I returned to using leaded solder........

I assume this is a similar effect that athletes experience after a period of altitude training.

[Robert M. Martinelli]

The main problem I initially found with most non-leaded solder (other than the poor flowing and higher melting temperature) is that virtually every joint looks like a dry joint.

+1

I used to be very proud of my soldering ability, after all I've been soldering since I was a little boy (d@mn it, that means I spent almost 40 years with a soldering iron in my hand), and it's VERY frustrating to see all the solder joints look like dry (here in Italy we actually call them "cold") joints, where I once could only see nice, shiny, perfect solder joints.....

I'm also worried about the mechanical resistance of the newer alloys, they're harder and stiffer so I expect them to develop crackles or to break more easily under heavy vibration (such as the ones present in a combo amp).

JM2CW

Best regards

Bob

[J M Fahey]

the right amount of lead. Well, until all lead is made illegal, at least.

Now, what am I going to cast my bullets out of?
Specially considering iron/copper/brass/etc. are forbidden.

[Robert M. Martinelli]

Now, what am I going to cast my bullets out of?
Specially considering iron/copper/brass/etc. are forbidden.

Yeah, I think many will have the same problem,....I used to cast my bullets using Pb (88%), Sb (8%) and tin (4%).....luckily I still have some "ready to melt" alloy ingots I prepared time ago using a Lyman ingot mold.....I will start to worry when the ingots will be almost gone...

(However, I'm a pretty good shot, so if I ever shoot someone, I think his last concern won't be about lead poisoning ).

Sorry for the "off-topic" post!

Cheers

Bob

[J M Fahey]

Well, it's not *that* off, considering we are talking ROHS here, which not only applies in Electronics.
Back to the point, I fully agree with not poisoning the planet, 100%, but I like to keep things in perspective: I find overworrying about the milligrams or micrograms of lead contained in a part itself ridiculous compared to the grams contained in the solder used to build the board where it will be mounted (so far that's being taken care of) and *both* absolutely ridiculous compared to the THOUSANDS of TONS (maybe even that is an understatement) of lead used in car batteries.
Even with the best recycling /disposal control, just a 10% of that which slips through is A LOT.
Oh well.

[guitarmike2107]

Since I don’t use circuit boards I have made a plan with an SSR to use on turret boards. this one is a DPST type seems to work well on my test voltage supply, I haven't tried it in a circuit but will do so shortly.

I will heat shrink the whole thing which will make it easy to use on turret board builds.

Someone may find this useful for replacing switching LDR's or coming up with an LDR type switching scheme that is RoHS compliant and doesn't require a circuit board.