Last typewriter factory in the world shuts its doors

[Mike]

On Fri, Apr 29, 2011 at 2:19 PM, Lennart Sorensen
<lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
> On Fri, Apr 29, 2011 at 01:40:47PM -0400, phiscock-g851W1bGYuGnS0EtXVNi6w at public.gmane.org wrote:
>> Vacuum tube audio amplifiers. I'm waiting for someone to come out with a
>> vacuum tube version of the iPod. There is enough of a resurgence in
>> interest that there is at least one technical book on their design, and
>> Creatron (on College at Spadina) is selling vacuum tubes. There are also
>> some low-voltage battery-operated models of tubes, one of which is the
>> basis for an educational kit.
>
> I thought vacuum tubes needed heaters to keep them working, which sounds
> rather counter to a portable battery powered device.  Also, why bother
> with a good amplifier if you start of with compressed to death input.
> Garbage in equals garbage out after all.
>

Well, as far as the heaters go, tubes have them built in (they're the
source the electron wind bias current...). Aside from warming up your
pocket a bit too much, tubes also tend to be a bit bulky and require
higher (200-600V) voltages to operate. That's a lot of AAAs ;-)

And no, no amount of tube amplification is going to make those early,
sibilant mp3s sound any better...

Now high voltage amplification for electrostatic speakers and
headphones... Tubes have never gone out of style. Just *try* and get a
Class AB transistor amplifier to do ~600V p-p!

It's funny: I just don't think of vinyl sound reproduction and tube
amplification as  belong to yesteryear. The Philips compact cassette,
now...
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