John, Hear are the RCA data sheets from each typ of 6146. I haven't looked, but maybe the mystery will reveal itself from the specifications.
http://www.mif.pg.gda.pl/homepages/frank/sheets/049/6/6146.pdf http://www.mif.pg.gda.pl/homepages/frank/sheets/049/6/6146B.pdf http://www.mif.pg.gda.pl/homepages/frank/sheets/049/6/6146W.pdf I know from my 20a projects that using an EL34 / 6CA7 at RF up to 20 meters is a formidable challenge, and not all EL-34's are the same. I was able to get up to 50 watts peak with a single tube, and that was considerable PD over-rate of the tube, and hence the little computer fan to cool it. I idled at 40 ma cathode, and 600 volts plate w/o dc thermal run-away using a Svetlana EL-34. Jim http://pages.prodigy.net/jcandela/CE20AQRO/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of John Lawson Sent: Sunday, August 28, 2005 11:15 AM To: amradio@mailman.qth.net Subject: [AMRadio] Valiant progress Thanks to Jim, Larry et. al. for the great advice on my Valiant restoration project. I'm very interested in the common wisdom re: the 6146 variants that 'work' in this rig. Now, I've been a boatanchor fan since they were state of the art - have done quite a bit of tube design, mostly audio though, and I do have quite extensive documentation on most tubes made in the last 100 years. So really there's probably no excuse for this question other than laziness - what exactly are the 6146 characteristics that the Valiant design "favors" over the other variants? A freind who has re-built a lot of these rigs says to only use 'plain' ones. In my ignorance, I bought a nice full set of 'W's and the transmitter wouldn't even resonate on any band. ;{} I put three 'B' s in the finals, and we're where we are now - OK on 20M and above, 'runs away' below that. What do y'all recommend for Valiant finals / modulator tubes? On the HV B+ filter issue - mine are iffy, were replaced sometime in it's history, but I'm going to renew them - what is the recomendation for a more 'modern' replacement - keeping in mind that I'm looking for the best AM fidelity I can squeeze out of this rig. Cheers John KB6SCO ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.10.16/83 - Release Date: 8/26/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.10.16/83 - Release Date: 8/26/2005
