UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Valve Items - Philips/Mullard Rimlock-to-Noval Transition

turretslug · 13th Sep 2019, 10:59 pm

Synchrodyne's first post #41 link highlights the fact that VHF/FM broadcasting in West Germany got underway early and progressed smartly, with the Graetz 154W and 156W radios mentioned featuring 2x EF42 pentodes- it would be reasonable to assume that these were deployed as VHF RF amp and mixer/oscillator, raising the question of how this valve would compare with the EF91 and EF80 in various roles. It may have had a brief reign in VHF Band I TV RF and IF usage in the UK but UK VHF Band II FM broadcasting probably got into gear a little late for it. On the plus side, it has a notably high gm (plus the very short and direct internal connections of the Rimlock construction), on the minus side it has only one cathode-connected pin.

13th Sep 2019, 10:59 pm	#44
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,396	Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition Synchrodyne's first post #41 link highlights the fact that VHF/FM broadcasting in West Germany got underway early and progressed smartly, with the Graetz 154W and 156W radios mentioned featuring 2x EF42 pentodes- it would be reasonable to assume that these were deployed as VHF RF amp and mixer/oscillator, raising the question of how this valve would compare with the EF91 and EF80 in various roles. It may have had a brief reign in VHF Band I TV RF and IF usage in the UK but UK VHF Band II FM broadcasting probably got into gear a little late for it. On the plus side, it has a notably high gm (plus the very short and direct internal connections of the Rimlock construction), on the minus side it has only one cathode-connected pin.