Michael Black wrote:
ken scharf ) writes:
I don't recall the url but I remember a 2-3 tube receiver from the 40's
that might be what you want. It was a simple superhet with a
regenerative detector. Used a 6k8 as the converter and a 6c8g as the
detector / audio.

They were called "supergainers" and apparently Frank Jones, of later
VHF fame, was a big proponent of them in the thirties.

The earlier Radio Handbook on that webpage someone posted about would
have them, the 1936 version or whatever. I didn't suggest downloading
that one since I had the impression the tubes available to the original
poster were miniature, and the book predates those.

Thanks, Mike, Ken. I'll have to take a look. I did manage to download
some of the files on designing circuits with tubes, and with the online
tube manuals I might be able to figure out something on my own. Still,
if anyone can think of where I can find something already made up that
I can use, I'd appreciate it.


Ralph

julian814 wrote:
Michael Black wrote:
ken scharf ) writes:
I don't recall the url but I remember a 2-3 tube receiver from the 40's
that might be what you want. It was a simple superhet with a
regenerative detector. Used a 6k8 as the converter and a 6c8g as the
detector / audio.
They were called "supergainers" and apparently Frank Jones, of later
VHF fame, was a big proponent of them in the thirties.

The earlier Radio Handbook on that webpage someone posted about would
have them, the 1936 version or whatever. I didn't suggest downloading
that one since I had the impression the tubes available to the original
poster were miniature, and the book predates those.

Thanks, Mike, Ken. I'll have to take a look. I did manage to download
some of the files on designing circuits with tubes, and with the online
tube manuals I might be able to figure out something on my own. Still,
if anyone can think of where I can find something already made up that
I can use, I'd appreciate it.


Ralph

HERE'S the link http://www.io.com/~nielw/3tubrcvr/3tubrcvr.htm

ken scharf wrote:
julian814 wrote:
Michael Black wrote:
ken scharf ) writes:
I don't recall the url but I remember a 2-3 tube receiver from the 40's
that might be what you want. It was a simple superhet with a
regenerative detector. Used a 6k8 as the converter and a 6c8g as the
detector / audio.
They were called "supergainers" and apparently Frank Jones, of later
VHF fame, was a big proponent of them in the thirties.

The earlier Radio Handbook on that webpage someone posted about would
have them, the 1936 version or whatever. I didn't suggest downloading
that one since I had the impression the tubes available to the original
poster were miniature, and the book predates those.
Thanks, Mike, Ken. I'll have to take a look. I did manage to download
some of the files on designing circuits with tubes, and with the online
tube manuals I might be able to figure out something on my own. Still,
if anyone can think of where I can find something already made up that
I can use, I'd appreciate it.


Ralph

HERE'S the link http://www.io.com/~nielw/3tubrcvr/3tubrcvr.htm
Oh, nearly forgot....
With a little head scratching, you can replace the 6K8 with a 6u8, 6ea8,
6x8 (etc) triode/pentode. Use the pentode as the mixer and the triode
as the oscillator. In many cases the inter-electrode capacitance inside
the tube will provide enough coupling from the oscillator to the mixer,
but you might need to use a gimick capacitor (twisted wires) from the
pentode grid to the oscillator plate. Other tricks are to connect the
pentode screen to the oscillator plate, or in the case of the 6x8, the
pentode grid 3 to the oscillator grid.

The 6c8 may be replaced by ANY dual triode (such as 12au7, 12at7, 12ax7,
6sn7,6sl7, etc....)

ken scharf wrote:
HERE'S the link http://www.io.com/~nielw/3tubrcvr/3tubrcvr.htm
Oh, nearly forgot....
With a little head scratching, you can replace the 6K8 with a 6u8, 6ea8,
6x8 (etc) triode/pentode. Use the pentode as the mixer and the triode
as the oscillator. In many cases the inter-electrode capacitance inside
the tube will provide enough coupling from the oscillator to the mixer,
but you might need to use a gimick capacitor (twisted wires) from the
pentode grid to the oscillator plate. Other tricks are to connect the
pentode screen to the oscillator plate, or in the case of the 6x8, the
pentode grid 3 to the oscillator grid.

The 6c8 may be replaced by ANY dual triode (such as 12au7, 12at7, 12ax7,
6sn7,6sl7, etc....)

I think we may be in business, here. Went through my selection of
tubes, and there's a 6X8 and a 12AX7A among them. Three other tubes
looked like they had promise - two 12AV6 and a 6BU6.

After I'm done with this post, I'm going to Google Images to see if I
do indeed have 2000 ohm headphones. I want to make sure, because
elsewhere I found a crystal shortwave radio that uses them as well.
That might serve my needs better, although it won't have those cool
glow in the dark tubes.


Ralph

After using Google images to track down pictures of 2000 ohm
headphones, I am satisfied that those are what I have. (Eight sets, in
fact.) Found out the one tube is a 6BJ6, not a 6BU6, but it does still
seem usable. Going to ask if I can make some trades with tubesandmore,
so I can find a good home for some of the headphones and possibly get
the tube sockets and transformers I need for my project.

Thanks again to everyone who has helped. Time for me to go do some
math. (Ugh!)


Ralph

julian814 wrote:
After using Google images to track down pictures of 2000 ohm
headphones, I am satisfied that those are what I have. (Eight sets, in
fact.) Found out the one tube is a 6BJ6, not a 6BU6, but it does still
seem usable. Going to ask if I can make some trades with tubesandmore,
so I can find a good home for some of the headphones and possibly get
the tube sockets and transformers I need for my project.

Thanks again to everyone who has helped. Time for me to go do some
math. (Ugh!)


Ralph

You can just measure the resistance of the phones with an ohm meter.
The result will be close enough to the impedance (I think in the era
they were made they didn't even measure impedance, just the resistance).


Also, I have a lot's used 12au7's. If you need a few you can have some
for the cost of postage.

ken scharf wrote:
julian814 wrote:
Michael Black wrote:
ken scharf ) writes:
I don't recall the url but I remember a 2-3 tube receiver from the 40's
that might be what you want. It was a simple superhet with a
regenerative detector. Used a 6k8 as the converter and a 6c8g as the
detector / audio.
They were called "supergainers" and apparently Frank Jones, of later
VHF fame, was a big proponent of them in the thirties.

The earlier Radio Handbook on that webpage someone posted about would
have them, the 1936 version or whatever. I didn't suggest downloading
that one since I had the impression the tubes available to the original
poster were miniature, and the book predates those.
Thanks, Mike, Ken. I'll have to take a look. I did manage to download
some of the files on designing circuits with tubes, and with the online
tube manuals I might be able to figure out something on my own. Still,
if anyone can think of where I can find something already made up that
I can use, I'd appreciate it.


Ralph

HERE'S the link http://www.io.com/~nielw/3tubrcvr/3tubrcvr.htm
Link to follow up... http://www.io.com/~nielw/3tube_xtal/3tube_xtal.htm