Philips A442 screen grid valve... Intro date? - UK Vintage Radio Repair and Restoration Discussion Forum

RadioHist · 26th Jul 2014, 4:47 pm

Have not been having any success in finding out the MONTH in 1927 when Philips first announced the availability of it's first screen grid RF tetrode the A442.

M-O-V claims to be the first-to-market screen grid RF tetrode with their S625. Don't know the year and month for its introduction but do know that there was a Marconi radio with this valve shown at the 1927 Radiolympia which was in late August or early September. Beating out RCA's official announcement of
their type UY-222 in October 1927.

I need to know where the Philips intro fits into this time line.

Thanks,
Robert

26th Jul 2014, 4:47 pm	#1
RadioHist Pentode Join Date: Aug 2009 Location: Charlotte, NC; USA Posts: 165	Philips A442 screen grid valve... Intro date? Have not been having any success in finding out the MONTH in 1927 when Philips first announced the availability of it's first screen grid RF tetrode the A442. M-O-V claims to be the first-to-market screen grid RF tetrode with their S625. Don't know the year and month for its introduction but do know that there was a Marconi radio with this valve shown at the 1927 Radiolympia which was in late August or early September. Beating out RCA's official announcement of their type UY-222 in October 1927. I need to know where the Philips intro fits into this time line. Thanks, Robert