1 Feb
2011
1 Feb
'11
2:29 p.m.
On 1 Feb 2011 at 21:48, Tony Duell wrote:
Cheap record playes over here tended to use the
turntable motor widing
and an autotransformre to run the valve heaters (series string
totalling around 100V) and get the HT (B+) by half-0wave rectifying
the mains.
> power tube with a 35Z5 rectifier and a 12SK7 (or other 12.6V pentode
> or triode).
There was a brief time when AC/DC/battery radios were offered that
could be switched between line and battery operation. A 117Z3 or
similar rectifier was used to power both the filaments and as a plate
supply for the low-voltage tubes in the receiver section. Later
versions used a selenium rectifier instead of the 117Z3.
--Chuck