[R-390] 3TF7 Ballast Tubes

[Tom Frobase]

You replace the 2 tubes that are in series with the Ballast V505 and 
V701 with 12BA6's and put a jumper between pins 2 and 7 on the ballast 
socket.  tom, N3LLL


On 2/18/2011 5:58 PM, Rick Popovich wrote:
> This is why I joined this list - I'm always learning something new.
>
> Which leads to my question; is the 12BA6 a DIRECT substitute for the
> 3TF7 ? - meaning no wiring changes are needed under the tube socket ?