Purple Glow

[ANDYLASER]

I seem to remember a thread about valves which emitted a rather nice purple glow when operating. Does anyone know which one this is, or more importantly what amp it was referring to and is it any good?

Thanks.

 

[Klimon]

You probably mean American / European voltage regulator tubes...

 

[Colt45]

0D3?

 

[Bandersnatch]

0D3?

0C3 is the same shade of purple/pink as 0D3. 0B3 is an absolutely beautiful indigo, but it isn't so bright...0A3 is of course orange( and quite bright ).
cheers,
Douglas

 

[Jeb-D.]

Some Xenon filled rectifiers also glow purple.

(picture from another thread, not mine)

An externally hosted image should be here but it was not working when we last tested it.

 

[EC8010]

Kids, don't do this at home...

Did that picture come from the "Most Dangerous Lash-Ups" thread?

 

[rknize]

0A2 in the Thomas amp:

 

[bereanbill]

I had an old Ampeg Bass amp with an 80 rectifier that not only glowed purple, but pulsed with the music....prehistoric lightshow !!!!

 

[jackinnj]

Some Xenon filled rectifiers also glow purple.

(picture from another thread, not mine)

ouchhhhhhh! don't operate a mercury vapor tube in that position.

 

[SpreadSpectrum]

ouchhhhhhh! don't operate a mercury vapor tube in that position.

Why? What's it do? Didn't all the Hickok testers operate the 83s in that position?

 

[jackinnj]

Why? What's it do? Didn't all the Hickok testers operate the 83s in that position?

In use, the tube is to be mounted vertically -- I have Hg rectifiers in my Hallicrafters linear amplifier:

 

[SpreadSpectrum]

Hmmm, but I wonder what the reason is. I have noticed a lot of loose chunks in a lot of the mercury tubes that I have seen. Maybe this is common and you keep the tube upright to keep them out of the plate structure?

 

[Miles Prower]

I seem to remember a thread about valves which emitted a rather nice purple glow when operating. Does anyone know which one this is, or more importantly what amp it was referring to and is it any good?

Purple glow is usually a bad thing. That means gassiness, followed by plate current runaway, and something usually poofs. If you're lucky, that'll only be a fuse. Some VR tubes and gas diodes will glow like that where it's perfectly normal.

What you may be referring to is the sky blue glow that comes from the excitation of cobalt ions that sometimes contaminate the glass. It's usually the RCA tubes that do this, as I've seen it with RCA: 807s, 6BQ6GTBs, and 6AQ5s.

Of course, you can always simulate this glow with blue LEDs.

 

[SpreadSpectrum]

It's usually the RCA tubes that do this

EH 7591s do this, if you are looking for a current production tube.

 

[Wavebourn]

I have the whole palette of colors in my first Pyramid model...

 

[hardwareguy]

EH 7591s do this, if you are looking for a current production tube.

Oooh.....just what I need for my HH Scott 299C!

 

[wrenchone]

Nice to know about the glow in the EH 7591s - I have a quad sitting around for use in a P-P amp to be built with some Fisher vintage iron. I used to enjoy the glow from the 7591s in my Scott LK-72B amp - never shoulda sold that thing. I have high hopes for a set of new-style Svetlana 6L6GCs (Reflector -built) I have set aside for an SE project.

I'm currently using RCA 1625s in my "Shrine" SE amp. I get the blue glow, but it was always pretty faint and only visible these days with the lights out. It's cool to see the glow flicker with the music, along with the occasional grunt from a hard-working output transformer. I was hoping for some pleasing blue glow from some of my screen-driven sweep tube amps, but so far, no joy. Maybe the sweep tubes shepherd the electrons a little more closely, so that there's less spillage.

 

[scott wurcer]

I seem to remember a thread about valves which emitted a rather nice purple glow when operating. Does anyone know which one this is, or more importantly what amp it was referring to and is it any good?

Thanks.

The old 60W Quicksilver monoblocks were particularly nicely colored purple. Wrenchone, have you forgotten the VR in that Dumont scope

 

[wrenchone]

It's been a while, Scott, and anyway, VRs are supposed to glow. I find the incidental deep blue-violet from the 7591s and the like more pleasing. It's a light show for free. Far be it from me to select a tube solely for that effect, but if I get it, I ain't complaining - it's cool.

BTW, the earliest glowing tubes I ever saw were some mercury vapor thyratrons at the Florida State accelerator lab. Mercury arc rectifiers also put on quite a show - I've seen pictures, but unfortunately not the real deal.