"Scott Dorsey" wrote in message
...
Antonio Vernucci wrote:
Can any one explain the rationale behind using both octal and loctal tubes
in
the SX-42?

Loctal tubes were really cheap on the surplus market at the time?

I believe the lone Loctal tube was a 7F8; at least this the tube used in my
SX-43. If you want to read more about this particular tube, check out the
volume on components from the MIT Radiation Laboratory series. If memory
serves, this dual triode was rated to much higher frequencies than any dual
triode that had an octal base. These tubes are still available NOS.
However, if you are willing to make an adapter or rewire the receiver, I
believe a 12AT7 can be used. Of course, if you want "museum quality", which
I think is rather foolish, use the 7F8.

73, Dr. Barry L. Ornitz WA4VZQ

NoSPAM wrote:
"Scott Dorsey" wrote in message
...
Antonio Vernucci wrote:
Can any one explain the rationale behind using both octal and loctal tubes
in
the SX-42?

Loctal tubes were really cheap on the surplus market at the time?

I believe the lone Loctal tube was a 7F8; at least this the tube used in my
SX-43. If you want to read more about this particular tube, check out the
volume on components from the MIT Radiation Laboratory series. If memory
serves, this dual triode was rated to much higher frequencies than any dual
triode that had an octal base. These tubes are still available NOS.
However, if you are willing to make an adapter or rewire the receiver, I
believe a 12AT7 can be used. Of course, if you want "museum quality", which
I think is rather foolish, use the 7F8.

73, Dr. Barry L. Ornitz WA4VZQ

This is true, it was a very high performance tube. But it's also true that
after the war a lot of equipment came out using surplus loctal tubes; I have
a Philco table radio that is all-loctal.

Incidentally, Barry.... welcome back. I don't think I have seen your name
on Usenet for more than fifteen years and it's great to see you here again.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Scott Dorsey" wrote in message
...
NoSPAM wrote:
"Scott Dorsey" wrote in message
...
Antonio Vernucci wrote:
Can any one explain the rationale behind using both
octal and loctal tubes
in
the SX-42?

Loctal tubes were really cheap on the surplus market at
the time?

I believe the lone Loctal tube was a 7F8; at least this
the tube used in my
SX-43. If you want to read more about this particular
tube, check out the
volume on components from the MIT Radiation Laboratory
series. If memory
serves, this dual triode was rated to much higher
frequencies than any dual
triode that had an octal base. These tubes are still
available NOS.
However, if you are willing to make an adapter or rewire
the receiver, I
believe a 12AT7 can be used. Of course, if you want
"museum quality", which
I think is rather foolish, use the 7F8.

73, Dr. Barry L. Ornitz WA4VZQ

This is true, it was a very high performance tube. But
it's also true that
after the war a lot of equipment came out using surplus
loctal tubes; I have
a Philco table radio that is all-loctal.

Incidentally, Barry.... welcome back. I don't think I
have seen your name
on Usenet for more than fifteen years and it's great to
see you here again.
--scott

I am not quite sure of the origin of the loctal base
but I think it was Philco. At any rate they made and used
them very widely in their radio sets. Philco was a large
supplier of automobile radios, I think for Ford. Loctal
tubes were supposed to be resistant to shaking loose when
subject to vibration.


--

--
Richard Knoppow
Los Angeles
WB6KBL