13 Volt Valves

I'm not really sure if these are a family of valves or not, but as several different types of British valves with B7 bases and 13V indirect heaters were produced I thought I'd list those I know of here.  These valves tend to be described as for series heater use in chains of 200mA or 300mA depending on the type, they are also described as suitable for use with 12V car batteries.  They seem to be variants of valves that exist with other bases and other heaters (26V and 4V), some are Catkin types.

One interesting point about these valves is that they seem to show the early British valves with their 4V 1A heaters (i.e. 4W) start a chain of developments that lead to 6.3V types in USA.  A problem with 4V heaters was hum resulting from the high current - the data sheet for the H30 triode remarks in it's low residual hum. 

 Name Type Maker Heater current Notes
 DH30Triode DD   300mA 
 H30 Triode  300mA Used by BBC as microphone amp in 1930s
 KT30 Tetrode  300mA Probably equivalent to N30 pentode
 L30 Triode  300mA Same characteristics as ML4
 N30 Pentode  300mA 
 W30 Pentode  300mA 
 8D2HF pentode Brimar  200mA 
 20D2Triode hexode Brimar 150mA  
 15D1Freq changer Brimar  200mA 
 15D2Freq changer Brimar  150mA 
 9D2HF pentode Brimar  200mA  
 11D3Triode DD Brimar  200mA 
 11D5 Triode DD Brimar 150mA 
 10D1 Duo diode Brimar 200mA 
 7D8 Output pentode Brimar 650mA Like 4V heater 7A3. Datasheet
 7D5 Output pentodeBrimar  350mA 
 13PGA Pentagrid Cossor 200mA 
 13VPAHF pentode  Cossor  200mA 
 13SPAHF pentode  Cossor  200mA 
 13DHATriode DD    
 VP1321HF pentode Mazda  200mA  Mazda octal versions exist
 VP1322HF pentode Mazda  200mA ditto
 HL/DD1320Triode DD Mazda 200mA  ditto
 HL13CTriode  Mullard 200mA 
 SP13C Pentode Mullard 200mA 
 FC13C Octode Mullard 200mA 
 VP13CHF pentode Mullard  200mA 
 2D13A/2D13C Duo diodeMullard  200mA (B5 base)
 TDD13C Triode DD Mullard 200mA 
 VO13 Octode Tungstram 200mA  
 VP13K RF pentode Tungstram 200mA  
 VP13B RF pentodeTungstram 200mA  
 HP13 RF pentodeTungstram 200mA  
 HL13 TriodeTungstram 200mA  
 DDT13Triode DD Tungstram 200mA  
 DD13 Duo diodeTungstram 200mA  
 PP13A Output pentodeTungstram  300mA  
 VP1321 Pentode  200mA 

Several of these valves are listed as used for ship transmitters and receivers in the 7th edition of Handbook of Technical Instruction for Wireless Telegraphists (Dowsett, 1942).  Which suggests they were in use during WWII.  A scan of the relevant page is attached here.

Octal base types with centre-tapped 26V heaters, i.e. can also be used at 13V include Osram KT33C and KT35 output tetrodes. 


There's a very interesting description of a 1934 (or perhaps 1933) GEC wireless using some of these valves at  http://www.classicwireless.btinternet.co.uk/gecd.htm
The service sheet for this set is available at http://www.radiomanuals.info/information/Broadcasters/sGEC%20AVC.pdf

Michael Saunby,
2 May 2009, 11:56