How a Vacuum Tube Is Made

[PhilGood]

This is the kind of stuff that gets my blood pumpin'.

Think he could make a VF14 deserving of an "M"?

I'm not that sure anyone needs to. What was so magical about the VF14?...no one seems to be able to explain. It had "special oxides in the filament" or had "a unique sound by under-heating the filament" as far as I've heard, but still...it was just a vacuum tube! It was a pentode wired as a triode, much like you could do with a 6AU6A. The grids are laid out almost the same. There are a few companies who have created drop-in substitutes using GE 408A and 407A with resistors to compensate for heater voltages. The jury is 6 to 6 on the sound, but some of the graphs that compare are compelling. Others will argue that missing the target by 1% means it won't sound like a U47 when in truth all U47's vary in sound by over 10%. So how do you hit that "magical" target?

I think its all snake oil.

 

[Twinhit]

I'm not that sure anyone needs to. What was so magical about the VF14?...no one seems to be able to explain. It had "special oxides in the filament" or had "a unique sound by under-heating the filament" as far as I've heard, but still...it was just a vacuum tube! It was a pentode wired as a triode, much like you could do with a 6AU6A. The grids are laid out almost the same. There are a few companies who have created drop-in substitutes using GE 408A and 407A with resistors to compensate for heater voltages. The jury is 6 to 6 on the sound, but some of the graphs that compare are compelling. Others will argue that missing the target by 1% means it won't sound like a U47 when in truth all U47's vary in sound by over 10%. So how do you hit that "magical" target?

I think its all snake oil.

It probably IS all snake oil.
I don't know. When I suggested the VF14 tube, I thinking about when telefunken decided to cease production. Like you, I wonder what it is about that tube that seems to make/break the value of a real U47. Granted, and I am betting there are very few 47 mics left that are 100% original and fewer still that work flawlessly given the nuvister mod that may have been used in the past. So.... with the so-called love affair with the 47, especially with all the aspiring clone designs out there I couldn't help but wonder why someone couldn't reproduce
the actual tube to original specs?? Barring low demand, productionwise, are there materials used in the original tube that might not meet certain regulations ie eviromental??
Maybe it's those "special oxides" I am thinking of.

IMHO, there is definitely more to a mic's sound than any one of it's components and that it is ALL of the components and the circuit design that contribute to a potentially great sounding mic.
It's been said, "If you want a U47 sound, buy a genuine U47" I take that to mean what it means but also that the 47 is a benchmark or bar to met and surpassed.
Because of the subjective nature, it is sometimes hard to say x brand model mic is the best and I presume that because there is no shortage of sound sources, there
is always going to be room for a new microphone for such and such sound that does the job unanimously better than another.

It's madness.

 

[stevieb]

Well, regardless if it's a sweet lullaby or not, I personally find the subject intriguing...

I found the SUBJECT intriguing, too, that's why I watched. I agree with about everything you said- v. cool that someone would put that kind of workmanship into something. But the vid was so slowly paced. Not saying it should go a double-speed, but man, I was literally dozing off. Perhaps the pace was deliberate, to convey a sense of attention to detail over production efficiency...