A while back there was a 12v tube thread.

I saw this:

http://www.thamesandkosmos.com/products/ra/ra2.html

advertized in September Scientific American. The ad (on the
builditplayit.com site) says it uses a "double triode" and
requires 8-AA batteries (nominally 12V).

I wonder if it is a 12V tube kit. Perhaps a 12AE7 or similar.

Anyone know?
--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA

Steven Swift wrote:

A while back there was a 12v tube thread.

I saw this:

http://www.thamesandkosmos.com/products/ra/ra2.html

advertized in September Scientific American. The ad (on the
builditplayit.com site) says it uses a "double triode" and
requires 8-AA batteries (nominally 12V).

I wonder if it is a 12V tube kit. Perhaps a 12AE7 or similar.

Anyone know?

Can't speak for the kit but I know some guys have successfully used a
plain old 12AT/AU/AX7 at 12 volts with acceptable results.

-Bill

Bill ) writes:
Steven Swift wrote:

A while back there was a 12v tube thread.

I saw this:

http://www.thamesandkosmos.com/products/ra/ra2.html

advertized in September Scientific American. The ad (on the
builditplayit.com site) says it uses a "double triode" and
requires 8-AA batteries (nominally 12V).

I wonder if it is a 12V tube kit. Perhaps a 12AE7 or similar.

Anyone know?

Can't speak for the kit but I know some guys have successfully used a
plain old 12AT/AU/AX7 at 12 volts with acceptable results.

-Bill

There were a couple of articles in Popular Electronics in the early
sixties about doing that. And oscillator and then an amplifier,
if I remember the sequence properly. From memory, the author
referred to them as "starved circuits".

I have a vague memory of trying one of them in the early seventies,
but I honestly can't remember if I did or didn't.

Michael VE2BVW

Bill wrote:

Steven Swift wrote:

A while back there was a 12v tube thread.

I saw this:

http://www.thamesandkosmos.com/products/ra/ra2.html

advertized in September Scientific American. The ad (on the
builditplayit.com site) says it uses a "double triode" and
requires 8-AA batteries (nominally 12V).

I wonder if it is a 12V tube kit. Perhaps a 12AE7 or similar.

Anyone know?

Can't speak for the kit but I know some guys have successfully used a
plain old 12AT/AU/AX7 at 12 volts with acceptable results.

-Bill


The ARN-6 direction finding receiver used 24 volts on the plates of
12SN7 tubes. I wonder how well they would perform at 12 volts?
--
?

Michael A. Terrell
Central Florida

On 15 Sep 2005 01:27:23 GMT, Steven Swift wrote:
A while back there was a 12v tube thread.

I saw this:

http://www.thamesandkosmos.com/products/ra/ra2.html

advertized in September Scientific American. The ad (on the
builditplayit.com site) says it uses a "double triode" and
requires 8-AA batteries (nominally 12V).

A goolgle for "space charge tubes" will probably turn up a lot
of info on low voltage tubes.

The Summer 2005 edition of Sprat, the GQRP club magazine, has a circuit
for a vfo using a XFY43 hearing aid valve/tube running off 12V. Better
stability than a fet oscillator, apparently.

--
Cheers,
Stan Barr stanb .at. dial .dot. pipex .dot. com
(Remove any digits from the addresses when mailing me.)

The future was never like this!

A number of Australian hybrid car radios of the 1960 period used
special valves based on 12v HT but the output stage used transistors.
Heaters were 6v with pairs of tubes wired in series. Tube types
included 6DS8, 6DR8 & 6ES8 for RF, Mixer, IF and detector stages.

These sets would not have worked with dry cells due to the use of
tubes with heated cathodes.

Simon.


On 15 Sep 2005 01:27:23 GMT, (Steven Swift) wrote:

A while back there was a 12v tube thread.

I saw this:

http://www.thamesandkosmos.com/products/ra/ra2.html

advertized in September Scientific American. The ad (on the
builditplayit.com site) says it uses a "double triode" and
requires 8-AA batteries (nominally 12V).

I wonder if it is a 12V tube kit. Perhaps a 12AE7 or similar.

Anyone know?

My project this winter is to build a single tube transmitter into an Altoids
box. I am sure that has been done before, but I plan to build in the entire
power supply and key.

It should work. Using an old geiger counter tube, I will use a AA battery
for the filament and will first try a 9 volt battery for the plate and
screen. That should be fine. If not, I will use either a 15 volt or 22
volt battery - but the 9 volt is cheaper.

Power will be low, but having a friend a mile away makes the power
requirement modest. CW only.

As a kid, I built a one tube broadcast receiver using an old acorn tube and
15 volt battery for the plate.

Colin K7FM

"While valves will work with only 9 volts on the plate they are high
impedance devices and so you will not get any significant power."

Depends upon what you mean significant. I just need a couple of milliwatts
to go a mile. He has a little cmos oscillator going into a final transistor
and keys the final transistor. The cmos oscillator runs constantly at a few
milliwatts. I can hear that, even with the final disabled, so it is simply
the blowby of a few mw oscillator.

Build a tube transmitter with power supply and keyer into an Altoids tin
seems significant.

Colin K7FM

COLIN LAMB wrote:

"While valves will work with only 9 volts on the plate they are high
impedance devices and so you will not get any significant power."

Depends upon what you mean significant. I just need a couple of milliwatts
to go a mile. He has a little cmos oscillator going into a final transistor
and keys the final transistor. The cmos oscillator runs constantly at a few
milliwatts. I can hear that, even with the final disabled, so it is simply
the blowby of a few mw oscillator.

Build a tube transmitter with power supply and keyer into an Altoids tin
seems significant.

Colin K7FM




Depends how low you want to go. I worked VK6 from 4 land with
4x2N2222As running about 750 mw out. If I had taken my rcvr to that
same relative anemic level, or if the other guy had taken his rcvr or
xmtr to that level, its doubtful that my rig would have "worked great".

hehe, as a joke, I and another guy decided to nix an obnoxious dx
buddy's success in pileups. Among many tricks, one was the signal
generator into a random-wire antenna that would effectively kill him a
half-mile away. "Hey, do you guys hear that carrier?"

You can do wonders with QRP stuff. I don't think the term "significant"
really applies.



-Bill

Hey, but your qrp signal was significant to the obnoxious dx buddy.

A very weak signal coming from Mars would be very significant.

Colin K7FM