Rare DARIO R7/14 directly heated small signal triode,~ RE084, tested "very good"

Description

Very rare DARIO  R7/14 directly heated small signal triode, comparable to Telefunken RE084
Description
R7/14 :
Very rare low power triode with Barium sputtered
filament,
directly heated with 4,0 VDC, 0,08 Amp. (measured by myself). Unfortunately I haven't found any data of this tube in databooks and the www.
Even "RÖHREN CODEX" only has an entry with the naked type name, but without any data!
By measuring I found that this tube behaves quite similar to Telefunken RE084 (same heating data, nearly the same I_plate and gm in the preferred point of operation of the RE084, same system construction). The tube offered obvously is a selected one because of it's stamp "services public" and an anchor stamp on the bulb.
Condition:
The tube is boxed and the box was opened by myself because of the inspection and the measurements. The tube in very good condition, without any visible mechanical or electrical defects and without gas. The imprints on the bulb clearly visible.
Emission tests:
1. Using U_plate =  100 VDC, U_g1 = 0 Volts, U_h = 3,7 VDC;  - U_plate connected to - U_h
Result:
I_plate = 5,9 mA  = 107% of 5,5 mA, the index (100%) value of RE084 according to *)
==>  very good
2. Using U_plate =  150 VDC, U_g1 = -4,0 Volts, U_h = 3,7 VDC;  - U_plate connected to - U_h
Results:
I_plate = 3,93 mA  = 98% of 4,0 mA, the index (100%) value of RE084 according to *)
==>  very good
At this point of operation
gm = 1,6 mA/V =  107% of 1,5 mA/V,
the index (100%) value of
RE084 according to *)
==>  (nearly very) good
*) see https://frank.pocnet.net/sheets/110/r/RE084.pdf
Remarkable:
The R7/14 offered showes a very good stability of I_plate over a wide range of heating voltage from 3,2 .... 4,2 Volts
!
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Achtung! Privatverkauf meiner Röhrensammlung!
Nur deshalb verkaufe ich die Röhren ohne Funktionsgarantie und Rücknahme als DEFEKT !
Attention! This is a private sale of my tube collection!
That's why I sell the tubes without warranty and return as DEFECTIVE!
Versand / Shipping:
Innerhalb Deutschland
im versicherten Paket mit DHL oder Hermes, Zusendung an Abholstation möglich! Andere Versandarten bitte anfragen! Angegebene Versandkosten beinhalten Verpackungskosten!
International bidders are welcome!
Shipping possibilites:
EU countries:
Packaging and shipping, registered and with tracking service up to a total weight of 5,0 kg with German DHL-Service for 14,00 Euro.
World Wide Shipping outside EU  **):
Packaging and shipping, registered and with tracking service up to a total weight of 2,0 kg with German DHL Standard Package for 22,00 Euro  (reduced fee for shipping to U.K. and Switzerland only : 19,00 Euro).
**) Attention:
The private shipping of parcels and packages with the German DHL shipping service from Germany to "overseas countries" is possible again in most cases! But because of health control measures and/or the decline of international airfreight capacities the shipping can be restricted or more expensive or can take more time than usual! This applies to some Amercian and Asian countries and can change at short notice.
You are welcome to ask me for the conrete shipping conditions for your destination country before you bid! And please
DO NOT PAY IMMEDIATELY
after reception of EBAY's automatically generated purchase confirmation notice, but give me the time to check the actual shipping situation with DHL and
WAIT FOR MY INDIVIDUAL INVOICE !!!
I
basically
do not ship without registration, insurance and tracking services!
Combined shipping:
I support combined shipping as far as possible.