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11.08
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...On Decision '08: McCain
and Obama's Tech Platforms (October
2008)
This article is very timely and
most appreciated. It's important for a voter to
be as informed as possible prior to making that
final choice in the voting booth. Thanks for the
research and content of this article!!
Hal Ferguson
IEEE Member
Basye, Va.
***
Neither candidate suggested that
we revitalize the hydroelectric industry to
produce more renewable energy. Hydro produces
17% of the world's electricity; the same amount
that nuclear energy produces worldwide. Hydro is
a renewable energy source that has zero
emissions; and the highest efficiency rate of
any of the renewable energy sources. In
addition,of the more than 80,000 existing dams
in the United States (Reference Hydro Review
magazine, "National Inventory of Dams", Sept
2006) there are over 20,000 of these existing
dams which could be retrofitted to produce over
30,000 MW of electrical energy (or approx. 30
nuclear plants) This means that no new
structures/dams would need to be built for this
production of electricity. Why is this source of
electricity not discussed?
David Clemen
IEEE Senior Member
Western Springs, Ill.
***
... On Tubescence (June
2008)
I was enjoying the article
“Tubescence” until I reached the final sentence,
I was expecting to bask in the glow of the pair
of 6L6s as they answered a rare distant station
on 40 meters Morse. Too bad to waste that power
on Beethoven. Much better to have constructed a
6V6/6L6 transmitter from the pages of the ARRL
Radio Amateur’s Handbook and maybe learned
something of value about tubes in the process.
I am off in the morning to an
ITU meeting in Genève. I sometimes wear my IRE
pin in my buttonhole but no one seems to know
what it is (including a few who should).
Larry E. Price
IEEE Senior Member
International Amateur Radio Union
***
In my early teenage years, I had
the opportunity to read a military manual that
was an introduction to vacuum tubes. Among the
many books I have read, that is one I will never
forget. My interest in it and its fascination to
me got me started in electronics and led me to
an enjoyable 40-year career in the semiconductor
industry. And, like a lot of others, I have my
extensive collection of vacuum tubes.
Ron Laugesen
IEEE Life Member
***
"Tubescence"
brought back some good memories. I'm a bit too
young to be expected to know much about tubes,
but my dad was an EE who never really made the
transition to semiconductors. So when he started
teaching me electronics and helped me get my ham
license, he based his teaching on vacuum tube
circuitry. At one point I had a great collection
of old tubes, including even a couple of huge
mercury-vapor rectifiers!
Steven DeRose
IEEE Member
***
Don Christiansen's article on "tubescence"
filled me with nostalgia. I am 75 and first used
"valves" after WWII in England. They were
probably war surplus. I was amazed that the 6L6
is still manufactured. I used it to build a ham
transmitter. I also used acorn tubes, with mixed
results.
One of our sons built an audio
preamplifier using tubes. He would adamantly
argue that the sound is better than that from a
solid state amplifier.
Brian Jones
IEEE Life Member
***
The statement "Transmitting
tubes create so much heat that the larger ones
require sophisticated water or forced air
cooling" gives the impression that semiconductor
successors are more efficient. Granted, a 4-400
tetrode thoriated tungsten filament takes 70
watts to light (while with another 100 watts
plate dissipation, two 2CX250 tetrode heaters
consume only 30 watts), but the overwhelming
majority of excess heat comes from the basic
efficiency limits of class A, B, or C operation,
to which high power semiconductor amps are also
subject. And, in the world of amateur radio,
both tube and semiconductor RF power amplifiers
are alive and well. Regarding audio applications
of "hollow state," it is interesting to note
that the WE-416, possibly the most advanced
microwave planar triode ever built, with a gm of
50,000 and extensively used in the AT&T long
lines TD2 microwave relay system, is now prized
by audiophiles as a low-noise magnetic
phonograph cartridge preamp!
Jules Madey
Director, Technology Development
New York State Thruway Authority
***
I am one of those who grew up
with tubes and learned solid state and ICs
before coming back to tubes. I own a number of
tube amps and can enjoy (imagination not
needed!) the glow — and more importantly — the
sweet sound and midrange bloom of a well tuned
tube amp. I favor classic Class AB amps (the
power waste of a Class A amp is over the top),
and for non-critical listening, a decent solid
state amp is there as a backup. But the heck
with 6L6s — they aren't particularly linear, fine
for guitar amps but not so nice for recorded
music. Instead, try a nice quad of EL84s, EL34s,
6550s, or KT88s — or perhaps, 7591As, 5881s, or
my current favorites, the new-fashioned KY-90s.
And use a good preamp! A restored 1960-era Heathkit AA-11 is running the show right now. I
like old iron and all my stuff is 30-50 years
old with new caps and guts. What fun I've had
bringing these beasts back to life!
I skip the cigar and cognac.
Perhaps a little wine. And I don't need Basie or
Beethoven. A good player and Nora Jones will
clearly explain the difference between lovely
valves and those nasty, gritty transistors.
James R. Benya
IEEE Member
***
Christiansen's article brought
back many pleasant memories. There is no way of
relating to the physics and mechanics of today's
VLSI as we could with transistors or tubes. Now
it is all magic black boxes.
I still have my RCA tube manuals
from the 60s — and a few tubes and tube radios,
too.
Keep the glow alive!
Barney Corwin
IEEE Member
***
I enjoyed the "tubescence"
article. I have been an engineer since 1982 and
a guitarist since 1974. I have not had an
opportunity to study the detailed differences
between tube and solid state amplifiers, but
have heard that, in addition to transient
handling, tube amplifiers create even harmonics,
not the odd harmonics of semiconductor amps,
especially when driven to distortion. I am not
sure about that, but can state firsthand that a
50-watt tube amp cranks way louder and with
better (rock and roll) sound quality than a
50-watt transistor amp. On the other hand, my
Wilder Engineering guitar amp, one of the first
guitar amplifiers, used germanium transistors,
which, in my totally subjective observation,
sounded better under R&R distortion than does
silicon.
Karl Ludwig
IEEE Member
***
I read (with both pleasure and
amusement) the article on "tubescence." As you
can see from my website
www.ralphbaer.com. I've been around
long enough to have built radios with 4-prong
triodes like the 20 and 21, and real-life
breadboards with wood screws holding their
sockets in place. I was a member of the
Institute of Radio Engineers, was once (in the
forties) offered a job by Lee deForest, and
worked on automatic surface noise reduction
before Dolby was out of knee pants.
I was also the proud designer of
a 2A3 push-pull 10-watt audio amp in 1939.
Balancing the hum from those triodes with their
directly heated filaments/cathodes using a pot
across the filaments (center to ground) never
quite did get rid of the that hum.
Those were the days (1938+) of
battles between the triode and beam-power tube
aficionados. I stuck with the triode crowd
because the majority of the harmonics generated
by those 2A3s or, later, 6A3s were even
harmonics when the tube was overloaded, while
the beam-power tubes like the 6L6 and the
smaller 6V6 made hash of music because they
generated mostly odd harmonics.
At age 86 I still sit at the
bench and design and build stuff. Every time I
build something that comes together on a
proto-board in minutes, I am reminded of how
much easier it is now. No more starting with a
large aluminum chassis, drilling quarter-inch
holes for the socket punch, drilling holes for
two nuts and bolts to hold the socket in place,
getting a sore arm from mounting the power
transformer, and wiring up the filaments. A day
would go by and all we had to show for it was
some tubes whose filaments would light up (they
kept the room nice and warm at a typical 6.3
volts x 0.3 amps apiece).
Does anyone know of any
publication that traces the technical path from
galena crystals through vacuum tubes,
transistors, integrated circuits, and
microprocessors with enough technical and
historical meat to tell us something we don't
already know?
As the original inventor and the
creator of the home video game industry, I am
often invited to speak to the subject of
electronics history. Typically, I take the
audience through 70 years of electronics using a
Power Point slide presentation that illustrates
representative equipment that I designed and
built (and frequently put into production). To
many in my audiences it is like ancient history.
While they enjoy it, most have a tough time
relating to it.
Ralph H. Baer
Manchester, NH
***
Just finished reading about "tubescence."
The author and I seem to have two things in
common — IEEE and the warmth of a toasty
low-distortion class AB1 amplifier. I grew up
and cut my teeth in electronics during the
vacuum tube era. I had to go back to school to
learn about transistors (you can teach an old
dog new tricks!)
We all miss those exciting days when there were
fewer theories and you tuned the transmitter
final until the plate was less cherry red and
the desk lamp was at its dimmest. You knew the
power supply you were working on was live when
the hair on your arms stood erect. Oh yes, and
upon picking yourself up from the floor after a
short nap, you knew better than to touch that
spot again before discharging that output filter
to ground. One learned the importance of
rubber-soled shoes and keeping one hand in your
pocket when probing with the other.
The kids today don't know and
probably don't care what us duffers did to form
the foundations for them to build on.
Anyway, to sum up, I loved
Christiansen's article. It brought back some
fond memories of our vacuum tube friends from
long ago.
Barry Tuttle
IEEE Associate Member
***
Long live Tubescence and The
Count, aye!
I am only 37 and am continually
amazed at the progress that was made during the
tube era. We are still mostly just replicating
those advances in semiconductors.
Thank you for the article and
the smile.
Brian Grantham
IEEE Member
***
I enjoyed reading your article
on vacuum tubes.
Back in the 60s and 70s we used
to purchase tubes in lots of 100 for the variety
of electronic equipment we built at Trott
Electronics in Rochester, NY.
When I retired and sold the
company in the late 80s the buyer had no
interest in the tube inventory, so I brought
about 1000 of them home.
Off and on over the past 20
years I have been selling them on eBay. The RCA
6L6GC had the greatest value followed by the GE
6L6GC. By offering matched pairs by testing on a
Hickcok 539B tube tester a pair often brought
$60 to $80.
Apparently the tubes made in
China, Russia, Slovakia and other countries do
not have the same sound when driven to
distortion in the Fenders guitar amplifiers.
I still have and occasionally use my old vacuum
tube Tektronix 'scope to demonstrate wave forms
to my interested grandchildren.
Marvin Trott
IEEE Life Senior Member
***
What a great article! Thank you.
To put my remarks in
perspective, I was born in 1930. My first "one
tuber" used an O1A. Later, I built a real power
amp, which had a pair or 2A3s in the output
I fixed all my neighbors' radios, and later
worked as a radio and then TV repairman. I was
drafted and landed in the Signal Corps. Luck was
with me, as I was sent to Ft. Monmouth, where I
went through the microwave and radar school.
Sent to Karlsruhe, Germany, I was an instructor
in radar repair — mostly on the SCR-584 search,
tracking and AA aiming radar. Lots of tubes
there, a klystron and magnetron, too.
After the Army, I went to
college on the GI Bill. Got my degree in
physics. Then my first job was at Cape
Canaveral, where they were using the SCR-584s
with a 9 ft. dish and a new receiver.
While in college I had gotten my
1st class radio operator's license. I fired up
the local UHF TV station early Sunday mornings
and signed off on Saturday nights. Lots of new
tubes on that job!
Now I'm a long-retired optronic
engineer from Kodak, but still have an old
Pioneer FM tuner for listening to classical
music. It's got tubes — nuvistors!
David Williams
IEEE Life Member
***
I really enjoyed your article on
"tubescence." As a licensed ham since 1961 and a
clinical engineer since 1967, vacuum tubes were
my first introduction to electronics.
Much of the physiological
monitoring equipment I worked on in the late 60s
relied on the ubiquitous 12AX7 for the input
differential amplifiers.
I would point out, however, that
there is a class of vacuum tubes still very much
in the forefront of today's imaging technology —
namely, x-ray tubes.
The modern-day tube in today's
64 slice (or even the newest 256 slice) CAT
(Computerized Axial Tomography) equipment is
capable of dissipating over 100 kW for extended
periods of time utilizing air and water cooling.
Some of these tubes can even produce dual energy
x-ray beams simultaneously.
So let's hear it for the vacuum
tube — still alive and well and contributing to
society.
Perhaps someday you might
consider a Backscatter article on the medical
uses of RF energy. Electrosurgical units, RF
ablation, and magnetic resonance imaging come to
mind.
Michael Mirsky
IEEE Member
***
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