My friend gave me a U.S ARMY SIGNAL CORPS tube VT-107A from 1942. Then it made it to the Netherlands in 1952 because it has a stamp on it written in Dutch and a date that reads: 29, X, 1952. My friend told me that was the year it was tested. If anyone is remotely interested i will upload pics, it has the box and everything.:bravo:
There's a lot of stuff like that floating around. It's not hard to believe at all. There are estate sales, Ebay, swapfests, all sorts of places and ways to get old vacuum tubes and new ones. The 6V6 is used in guitar amps to this day and they rightly say that most solid state amps cannot reproduce that sound. I used to actually repair tube-type radios and amps, as a hobby mainly. Someone who doesn't mind an itinerant lifestyle and tobacco smoke could run around the U.S. and keep a good income going repairing those, if he can get them to pay enough to cover expenses and pay a decent profit, which a lot of them don't want to do but they'd better if they want their stuff to work. Vacuum tubes still make good music and I've never heard solid-state shortwave radios that could sound better than some of my old tube receivers.
I should have posted the pic when i had it, now i cant find them. edit: bit i will look for them. Thats what my friend does, he stays in one spot though and repairs amplifiers. You mean tobacco smoke in bars??? yeahPlease Register or Log in to view the hidden image!
Here is a picture.Please Register or Log in to view the hidden image! http://en.wikipedia.org/wiki/ImagePlease Register or Log in to view the hidden image!iode_tube_schematic.svg
Bull. That's not a picture of it at all - just a simple drawing of a diode tube. The VT-107 is a tetrode and here's an actual picture of the beast: http://www.tubecollector.org/6v6.htm
If you go to music production and sound engineering fora, they'll tell you about how tubes give "clarity, big bottom, crunch, warmth, fullness, life, cream, definition, etc" to simple sounds and instruments (even the digital ones) passed through them, and that this is impossible to mimic digitally no matter how hard you try. Like religion, I decided that these people were all talking crap because they couldn't seem to make their minds up... A non-linear response (not necessarily with a continuous 1st derivative, though that has the obvious advantage of applying bounded distortion and therefore decreasing frequency aliasing), with asymmetry (for those elusive odd overtones), some signal-dependant capacitance, and you have yourself a digital vacuum tube. Unfortunately, mid-level producers and engineers often have large budgets and not enough electronic expertise or simple scepticism.
The thing is, it's that non-linearity along with all the harmonics generated that will always prevent digital music from sounding quite as "true" as analog. It's also the harmonics that distinguishes one human voice from another. Ten different people can sing the exact same not but will still sound different because of harmonics and differences in structure in their physiological structures. (Throat diameter, length, shape of sinus cavities, etc.)
Actually, there is a simple reason that tubes are prefered by musicians/etc over solid state. Tubes predominately generate odd order harmonic distortion. Semi's although lower in distortion overall, produce mostly even order. Musically odd order sounds pleasant and even like trash.
You still need to start with a good amplifier, some are real forgiving as to tubes and can handle ordinary tubes. Believe it or not there are software rigs that are very good. I never heard that before. There is no way to change that? What about all through software generating\simulating odd order harmonic distortion?
As I said in my previous post, doing odd harmonics is simple. Okay, let's say you have a normal non-linear transfer function, like tanh() (which, natively, eats up a ridiculous amount of CPU, but may be approximated with a few tricks). Here you have bounded distortion (no sharp edges, and so no infinite harmonics) and all the harmonics are even (when you pass a sine it will give another symmetric wave as output). To make odd harmonics the procedure is simple. Signal -> +DC -> tanh() -> dc remover (HPF). The level of asymmetry may be controlled by adjusting the strength of the DC signal. Obviously, the dc remover can't be just any HPF, but must be designed with just the right poles and zeros (no, simply subtracting tanh(DC) won't work, due to the non-linear nature; this is basic electrical engineering).
