2 Cunningham C-11 (WD-11) amplifier vacuum tubes. TV-7/U test strong.

Description

2 Cunningham C-11 (WD-11) amplifier vacuum tubes. TV-7/U test strong.
2 Cunningham C-11 (WD-11) amplifier vacuum tubes. TV-7/U test strong.
Click images to enlarge
Description
Pair (2)
Cunningham branded (RCA)
C-11 (WD-11)
Amplifier vacuum tubes.
Both TV-7/U test strong.
Up for bids is a pair of hard to come by, good testing Cunningham branded C-11 type triode vacuum tubes.
The C-11 is exactly the same as the WD-11.
Cunningham tubes were made for RCA who, under a unique contract, had to sell them to Cunningham at 20% below wholesale.  No mention of RCA was allowed on any tube, tube carton or data sheet.
Both tubes are identical in appearance and construction and have tight bases.
Both have the Cunningham "C" logo hot stamped on the base and inside the top of the tube.  Both bases read, "Cunningham C-11".
While most WD-11's are offered with "good emission" or "good filament,"  neither statement reveals the actual strength of the tube.
These WD-11's were tested for transconductance (Gm), shorts, noise, and gas
on my Dan Nelson calibrated TV-7/U tube tester using a digital meter for greater accuracy.  I used
a custom-made tube socket adapter and test settings for the type 864/VT-24 (same filament requirements and similar characteristics as the WD-11).
The TV-7 minimum recommended value (65%) for the WD-11 (864) is 16 (Gm=400).   WD-11's are historically known to perform well below the 65% minimum recommendation.
As pictured, with TV-7/U test results and Gm:
Tube 1= 18   Gm= 450
Tube 2= 15   Gm= 375
WD-11's and other early 1920's radio tubes are best suited for use by those with a working knowledge of radio restoration and vintage electronics.  As such, they are sold with no returns.   If you are familiar working with these tubes, you will love them!
These Cunningham C-11's would be a perfect addition to your restored Radiola III or any of the other five early radio receivers Westinghouse made for RCA that use these very hard to find tubes.
They will ship in sturdy vintage tube cartons, double bubble-wrapped and carefully packed in the upright position to ensure they arrive safely.
Click on any picture to enlarge it and get a better look at these strong testing Cunningham branded C-11 (WD-11) amplifier tubes.
Read my feedback!
I pack and ship to you, the way I would want you to pack and ship to me.  I strive to ensure your entire buying experience rates 5 stars!
Winning bidder makes payment within 2 days
of the auction with
USPS Priority Mail delivery.
Please read the “fine print” below!
Thank you for bidding & Good Luck!
1. Questions?? Please contact me BEFORE bidding!
2. As with all used electronics, this item, unless stated otherwise, is
sold as-is with no guarantees.
3. Returns are only accepted where
my description was inaccurate.
The pictures are a major part of the description. Enlarge and preview them before bidding, please.
4. Payment to be received within 2
days
of the auction.
5. Winning bidder in the State of Florida adds 7% sales tax.
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