RoHS and tubes

[gbono]

So what will happen to companies selling products with tubes, that as far as I can see, will never be RoHS compliant? As I understand it an MI company here in Petaluma CA is concerned about selling products in Europe after 2017 - since they don't have a RoHS solution.

So maybe you take a depletion mode MOSFET with a cheap uprocessor (it controls the bias, voltage regulation, LEDs, etc) and you stuff this into a glass "bottle" with the requisite pin outs. The LEDs give you the "look" of a tube (complete with a red plate mode if the grid bias is interrupted ;-) You could even have the processor "apply" distortion that would make pleasant sounds. I had a friend try to sell this concept and prototype hardware 15 years ago without success maybe it's going to be a product now?

[pdf64]

What is the issue with RoHS for tubes?
Pete

[Enzo]

Lead bearing solder in the pin base? But that could be replaced with lead-free.

Maybe the cathode coating material has something toxic?

[gbono]

Lead bearing solder in the pin base? But that could be replaced with lead-free.

Maybe the cathode coating material has something toxic?

Not a tube expert but I've read about thoriated filaments (cathode) and barium getters. While not technically RoHS concerns these are radioactive or very reactive materials that are considered health concerns.

[Mick Bailey]

Does anyone remember the Carlsbro amps with plug-in MOSFET 'valves'? - they had a glowing LED. Think they were late 70s.

[Steve Conner]

There are a few companies selling solid-state tube replacements. The Retrovalve and AMT Warmstone spring to mind. Every day someone brings out a new 1200V silicon carbide MOSFET so the future is bright for solid-state power tube replacements.

The quality of tubes seems to get worse every day. I'm experimenting with solid-state amp designs as a backup plan. I would rather design the circuit from the ground up to sound good with transistors, than try to stuff transistors into a circuit that was designed to sound good with tubes.

[soundmasterg]

Not a tube expert but I've read about thoriated filaments (cathode) and barium getters. While not technically RoHS concerns these are radioactive or very reactive materials that are considered health concerns.

Solid state production uses chemicals that are every bit as bad or worse than what is used in tube manufacture. Once the tube is made, unless you're sitting there licking cathodes for years, there aren't any safety concerns, especially if the bottle is still sealed up. ROHS already started in Europe, Japan, and China among other places. It isn't applicable in the US thankfully, but if anyone wants to sell worldwide they have to make their products ROHS compliant. I personally think that even though we know lead is bad for the environment, the whole lead-free thing was sold as an environmental thing but it was really an economic thing and a sneaky way for companies wanting to have more sales to get it passed. An organ company I used to work at changed their warranty on their products from 50 years to 10 years to 6 years since 2006, which ROHS took effect, because they didn't think their products would last for that long anymore.

Greg

[Jazz P Bass]

Yeah, Cathode Licking.
Yum.

[Mick Bailey]

Some of my customers have abandoned tubes in favour of solid-state, solely due to tube reliability. The biggest problem is power tube rattle and microphonics. Years ago I'd hardly ever come across this, now it's all the time.

Good players still sound good whatever the amp. They want reliability above all else.

[gbono]

There are a few companies selling solid-state tube replacements. The Retrovalve and AMT Warmstone spring to mind. Every day someone brings out a new 1200V silicon carbide MOSFET so the future is bright for solid-state power tube replacements.

The quality of tubes seems to get worse every day. I'm experimenting with solid-state amp designs as a backup plan. I would rather design the circuit from the ground up to sound good with transistors, than try to stuff transistors into a circuit that was designed to sound good with tubes.

So far there are no production power tube SS replacements but AMT is testing protos. Retrovalve has some 12AX7 like replacements.

Yes the future looks good for a SS tube replacements and it looks like they will be needed soon. The installed base of vintage amps that will need replacement tubes is hard to calculate. Like LED "light bulbs" SS tube replacements will have a steep increase in demand until the market saturates and the long lifetime of the product flattens the demand curve.

[defaced]

Not a tube expert but I've read about thoriated filaments (cathode) and barium getters. While not technically RoHS concerns these are radioactive or very reactive materials that are considered health concerns.

In other industries (welding electrodes in this case), thorium can be replaced by lanthanum or cerium. The biggest EHS issue we run into with thorium is the dust created during grinding (like for sharpening thoriated tungsten electrodes - 2 wt% is the most common concentration used in this application). Otherwise, it's generally it's not a concern. I wouldn't be suprised if lanthanum or cerium could be used in tube applications as well (or maybe they already are... I honestly don't know).

[Steve Conner]

I don't think any of the tubes used in guitar amps contain thorium. Hi-fi is a different matter, the 304TL has a thoriated tungsten filament and some crazy-ass audiophiles have used it.

Yahoo! Groups

[pdf64]

I think the scope of RoHS / RoHS2 is limited to mercury, cadmium, lead, chromium VI, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE), see clause #7 of http://eur-lex.europa.eu/LexUriServ/...88:0110:EN:PDF
Also tubes can be seen as being spares / consumables for equipment produced prior to RoHS (rather than equipment in their own right); RoHS acknowledges that repair is beneficial and so spares need to be available, see clause #20
So RoHS2 may not be a significant compliance problem for a continuing supply of tubes in the EU.
Pete