[Boatanchors] VT 27 = Type 30 = ?

[Al Klase]

William Howard wrote:
> .....
> Is a Type 30 tube the same as a Type 40 as far as use is concerned? What
> is the basic difference?

Hi Bill,

The 40 is a high-mu (high voltage gain)version of the 201A 
using the same 5-volt 250-ma filament.  These are designed 
to be used with a 6-volt storage batter for the filament 
supply.  As far as I know the 40 is pretty rare.

The 30 was also developed from the 201A, but uses a 
low-power filament designed to draw just 60 mA form a single 
2-volt wet cell. (or, sometimes, two 1.5 volt drycells with 
a filament rheostat)  Performance is more like an '01A than 
a 40.  These were used widely in portable equipment.

All pin-outs are the same.

Regards,
Al

-- 
Al Klase - N3FRQ
skywaves@bw.webex.net
Flemington, NJ 08822
Web Page:  http://www.webex.net/~skywaves/home.htm