Yes, we could swing the grids of those tubes quite a ways before encountering enough non-linearity to produce a significant amount of intermod, Andy! The old original AMECO tunable vacuum -tube preamp, that I borrowed from Bill, K4CIA, worked really well with my KAZ terminated RX loop for the low bands. It was connected to the receive antenna port on my FT-1000MP, so I wasn't blowing FETs!
My electronic design career began before the end of the vacuum-tube era, and I used the 6DJ8 commercially in some VHF monitor receivers, as a cascode RF stage in the front-end. 73, Charlie, K4OTV -----Original Message----- From: Andy Ikin [mailto:[email protected]] Sent: Sunday, August 25, 2013 5:16 PM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Thirty years ago I used 6DJ8 (E88CC) to solve a third order IMD problem with tuned loop that was using J310s. The IMD was caused by Radio Free Europe on 13m. 73 Andrew ----- Original Message ----- From: "Charlie Cunningham" <[email protected]> To: "'Andy Ikin'" <[email protected]>; "'Topband Reflector'" <[email protected]> Sent: Sunday, August 25, 2013 9:14 PM Subject: Re: Topband: Anyone have a boat load of J-310s? > Of course, a 12AT7, or better, a 6DJ8, would be excellent preamps as > well, > and aren't so sensitive to transients etc. :-) (Showing my age, I > guess!) > > -----Original Message----- > From: Topband [mailto:[email protected]] On Behalf Of Andy > Ikin > Sent: Sunday, August 25, 2013 3:58 PM > To: Topband Reflector > Subject: Re: Topband: Anyone have a boat load of J-310s? > > As far as am aware On-Semi still make the TO-92 J310. Fairchild ceased > production about 2 years back. I did a last time buy from Mouser for > several > > thousand J310 and the much more linear J309. > > 73 > > Andrew Ikin G8LUG > > > _________________ > Topband Reflector > > _________________ > Topband Reflector > _________________ Topband Reflector
