[Boatanchors] AR-88LF HB Pre-selector: UPDATE

[Edward Swynar]

Good Day,

Wow, and DOUBLE wow...!

I did some research through my 1971 edition of the "Sylvania Receiving Tube Manual", in a quest for possible "hotter" tube substitutes for the 6DK6 that I placed inside my recently homebrewed AR-88LF pre-selector: 

http://www.flickr.com/photos/15888272@N05/?saved=1

I found several with the same pin-outs as the 6DK6, but by far, *THE* hottest candidate appeared to be the 6JK6 (almost TWICE the transconductance / mu of the former)...and, as GOOD luck would have it, ye olde junque box yielded a "primo", NIB Sylvania-brand 6JK6. 

I''ve just finished installing it inside the pre-selector, and as I said earlier, wow and DOUBLE wow...! This thing is REALLY smokin' now --- indeed, on the lower frequencies, I have to retard the pre-selector's RF gain somewhat to keep it from "taking off".

But what a minor inconvenience, when compared to the tremendous and VERY worthwhile improvement this small tube has afforded the rig's overall sensitivity...

If you're at all contemplating the construction of a pre-selector for YOUR BA receiver, do consider acquiring a supply of the 6JK6 tube --- I don't think you'll regret your decision!

~73~ Eddy VE3CUI - VE3XZ