I have to agree with the other posts and say that its probably not worth
the effort. If the primary reason for the effort is to improve
sensitivity, a tunable RF preamp (e.g.: Ameco PCLP) with a decent n.f.
will oft times work wonders. I use one of these in-line with the
antenna selector of receivers such as the RBS, RBM, BC-348, BC-312,
various older Hammarlunds and Hallicafters with excellent results on the
higher bands. One size fits all!!

wrote:
Is it possible to replace certain octal tubes with equivalent miniature
in an older receiver and would there be an performance improvevment?

Just mainly looking to boost performance.
Any advice, thoughts, comments appreciated.

Thanks...Gil