Many of the newer UV LEDs are down into the 3-4 volt range at power outputs of up to a few watts...
my glasses have selfdimming plastic lenses activated by uv.....normal glass shields the uv, lenses cant dim 😉 tested this
only pure quartz glass is uv transparent, but has worse mechanical properties, not used in tubes.
Well, mercury is bad. But retro tech is cool. So with adequate precautions, it should be quite safe.
Recently discovered while visiting a valve factory that mass produced ones often used mercury diffusion pumps. Some probably still do. World perhaps explain the blue glow on my last Ebay purchase.
To lessen any wide band RF faff, local resistance and inductance will help.
Recently discovered while visiting a valve factory that mass produced ones often used mercury diffusion pumps. Some probably still do. World perhaps explain the blue glow on my last Ebay purchase.
To lessen any wide band RF faff, local resistance and inductance will help.
Those that do use mercury rectifiers and thyratrons, how do you supply the high curent 2.5 volt? transformer/smps/other?
Yep, transformers.
Have some meaty thyratrons which require 2 large transformers each. Shame they would be no good for audio as the amp would be wonderfully heavy.
Have some meaty thyratrons which require 2 large transformers each. Shame they would be no good for audio as the amp would be wonderfully heavy.
This is an old wives' tale. That question was asked 8 years ago, and answered Here. Glass is opaque to UV. If you want UV, you need fused quartz. Other light sources that use fused quartz, such as Hg or Na arc lamps enclose the quartz tube in glass to block the UV.
If this really was a problem, there'd be a lot of blind hams around, but there aren't.
As I said before, the main advantages to Hg vapor diodes, such as low, and consistent, forward voltage are also done, and done better, with Si diodes that don't require another hole in the chassis, separate heater PTXs, or generate the RF interference and noise of Hg diodes. Besides, I can't really see any benefits other than glowey bottle kewelness for audio. I don't see any use for these myself.
What still has me a bit confused is why people seem to not be using thyratrons as both rectifiers and regulators in one go. The few examples I see use the gird as anode and that is it. Even in that case it seems more logical to just use the anodes and trigger the tube all the time
RCA thought there was a UV danger back before there were any significant (American) national legal safety guidelines. We should all be very strict with our own definitions of "safe" because it's not about us. Nobody gives Rat's A$$ One about you or me. But we need to take every possible precaution not to hurt anybody else. Children, grandchildren, pets. Don't be that guy, when it's so easy to not be.
All the best fortune,
Chris
All the best fortune,
Chris
Yeah. Mercury is pretty bad stuff.
Some production equipment used (and may still use) mercury diffusion pumps to evacuate the valves. And being quite well versed in vacuum equipment, it appears that on the rotary table type evacuate/heat/seal machines, there's not a lot of time per valve and the pumps get quite abused. Suspect the net result is at least a little contamination of the inside of valves pumped with such systems. It would explain the blue glow on some I have.
Also, just so you know. There's some enthusiasm to bring back valve manufacture to the UK. They will be using turbomolecular pumps and not mercury as I've stepped forward to assist and have a personal aversion to the stuff. And some spare turbo pumps...
Some production equipment used (and may still use) mercury diffusion pumps to evacuate the valves. And being quite well versed in vacuum equipment, it appears that on the rotary table type evacuate/heat/seal machines, there's not a lot of time per valve and the pumps get quite abused. Suspect the net result is at least a little contamination of the inside of valves pumped with such systems. It would explain the blue glow on some I have.
Also, just so you know. There's some enthusiasm to bring back valve manufacture to the UK. They will be using turbomolecular pumps and not mercury as I've stepped forward to assist and have a personal aversion to the stuff. And some spare turbo pumps...
interesting - those thyratrons tubes are both the rectifiers and pass devices, of a voltage regulator circuit.
Exactly why I find it so weird to see them only being used with their grid as anode. Okay the design v4lve lover linked uses an ungodly amount of iron but I suppose a lot of that has to do with reliability and the quality of capacitors in that time
i think choke input is pretty much required for mercury rectifiers. Schematics that I have seen used 8H or 10H as the first L filters. So, hunt Ebay for those vintage UTC and Chicago chokes.
haha those are more expensive than having them made brand new
157M Hammond Manufacturing | Mouser Nederland
Those Hammond chokes likely wont stand the voltage, the old chokes have their maximum working voltage stated on the pot.
most of them have a 400+ volt rating. But no worries if I ever venture into this territory I'll pass by you anyway 😀
Yeah those 25 euros can be easily added and it makes it prettier 🙂
out of curiousity, are the RF chokes also still a thing?
out of curiousity, are the RF chokes also still a thing?