This usage of a miniature tube socket and plug as a connector / plug
combination was prevalent in 1970s amateur radio designs (e.g. Drake,
Kenwood TS-520/820, Icom 22S).

This connector / plug combination was smaller than the Amphenol / WPI series
86)
Octal socket / plug that was used in the 1950s and 1960s.
http://www.triodeelectronics.com/amphenol.html

Modern DIN and mini-DIN connectors replaced the usage of miniature tubes
sockets and plugs in the 1980s and 1990s.

Drake used 9-pin and 7-pin miniature tube sockets in the chassis for its
Noise Blanker option. The noise blanker (when installed in the radio) had a
7-pin or 9-pin plug (depending upon specific noise blanker and radio)
attached at the end of a cable that plugged into this chassis mounted
socket.

Drake shipped a factory supplied jumper plug, when the noise blanker was not
installed. Alas, after 30 years these jumper plugs routinely disappear.
It is not uncommon to find this problem in Drake radios, due to eBay sellers
stripping the noise blanker from a Drake radio (like the optional crystal
filters) to gain a few more dollars from the radio carcass --- just like
auto salvage yards.

The Drake R-4C (s/n 27893) currently on my workbench did not have its
factory jumper plug. Someone had crudely soldered 2 wire jumpers to the
underside of the 7-pin noise blanker socket. Most likely the seller
extracted the noise blanker for a quick $100. Besides being a terrible
soldering job (definitely not very talented), it consumes time for the owner
to add the noise blanker option in the future.
I prefer to restore my radios toward original (while the parts are still
available) and
appreciate the ability to "plug in" the optional Drake noise blanker for
routine
testing.

Fortunately, these parts are available for the Drake or radio restorer.
=======================
Leeds Electronics in Brooklyn, NY has both the 7-pin and 9-pin miniature
plugs !!
(Leeds is an old NY Radio Row company that moved with WTC was built in
1960s). Leeds Electronics has a number of other hard to find items for
radio
restoration.

Leeds Radio & Electronics
68 North 7th Street
Brooklyn NY 11211
Telephone: 718 963-1764

7 pin miniature plug - fits sockets for 1L6, 6AU6 etc [USED]
good for making tube adapters and test jigs (rife) $1.50
(OUT OF STOCK)
http://www.leedselect.com/images-sockets/plug-7pin.JPG

7 pin miniature plug -fits sockets for 1L6, 6AU6 etc
good for making tube adapters and test jigs with
screw on back shell - NOS $4.00
[This is the part that used in my Drake R-4C,
identical to Kenwood's 9-pin VFO plugs - see below]

7 pin miniature cable mount socket - fits plug above
good for making tube adapters and test jigs with
screw on back shell - NOS $4.00
[This is a CABLE MOUNT socket - mates to above]

9 pin shielded plug - made by Vector (rfe) $4.00

9 pin miniature plug fits sockets for ECC-83, 12AX7
good for making tube adapters and test jigs (rfe) $3.75
=======================
A 9-pin jumper plug is required for the external VFO socket on the
Kenwood TS-520/820 back panel for proper operation of the radio.
The Icom 22S uses a 9-pin socket for an accessory socket.

Kenwood continues to sell the 9-pin plug and screw on cap:
Kenwood part number: E05-0901-05 for $ 5.00
This is available through its parts distributors:

East Coast Parts
http://www.kenwoodparts.com/

Pacific Coast Parts
http://www.pacparts.com/

UK also has 2 parts suppliers:
Acoustic Services LTD
142 Uxbridge Road
Hanwell
London W7 3SL
Tel no: 0208 579 2872
Hours: Monday to Friday 10.00 to 5.00

Fullers LTD
Riverside View
Wickham Market
Ipswich IP13 0TA
Tel no: 01728 746500
Fax no: 01728 746900
E-mail:
Hours: Monday to Thursday 9.00 to 5.30, Friday 9.30 to 4.30
=======================

I hope this information will help other Kenwood, Drake and radio restorers
in finding parts.

Greg
w9gb

Wish I'd known that. I just bought a small quantity of 9-pin plugs
just to get one or two. Oh well, maybe someone else will need them...

Barry - N4BUQ