Hi Byron, Good question. A few years ago, I tried all of the possible substitutions for it and came to the conclusion that they did not improve the s/n test. And, they all deteriorated the operation of the Carrier Level meter. See my doc on our website on page 2 for more info: R390A Fix Non-Linear CL Mtr.pdf (r-390a.net) <https://www.r-390a.net/R390A%20Fix%20Non-Linear%20CL%20Mtr.pdf>.
The following info about 6DC6's is from Jacques Fortin: For your “Philips” 6DC6s, would you mean ECG-Philips ones (formerly Sylvania) of some European-made Philips branded ones ?? Maybe they were not made as “real” 6DC6… rebranded 6BZ6 ?? Or maybe worse: I have one 6DC6 with an etched-in-glass number, no brand, but on the flip side, you can still read, very faint, in the RCA numbering style: 6CB6A ! And guess what: this unit tests as a sharp-cutoff tube, not a semi-remote cutoff one… The net of it is that you should use a 6DC6 of the brand that provides the best s/n and Carrier Level meter operation. Regards, Larry On Sat, Jun 29, 2024 at 7:23 PM Byron Tatum <[email protected]> wrote: > Hello- If I can impose for some more tube advice or commentary. I have > read in more than one post that some prefer the 6BZ6/6JH6 in place of 6DC6 > for RF amp in the R-390A. I have been through many of these receivers over > the years and have found the 6BZ6 in that spot in some. Does anyone have > any supporting evidence for this substitution, or experiment results from > subbing? I don't like to sub tube types and feel the design engineers chose > the 6DC6 for a good reason. I myself have not played around with this > substitution yet.Thanks,Byron W5FH > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
