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Heatercathodeshort · 28th Feb 2021, 5:12 pm

It is not surprising that later versions of the TV22 employ EF91 valves. The later receivers types TUG 26,TUG34, TUG34A and TUG36, the later being one of the first to incorporate band 3, all sport EF91 valves. They perform just as good as the B9A EF80 and were probably a lot cheaper to buy in considerable bulk from Mullard.

Strangely the unscreened EF91 is not provided with an external screening can as is the norm with most receiver chassis. The EF80 is internally screened. The overall gain of the TV22 is fair for what it is but any extra stages of I.F. amplification may have created an instability problem. The EF91 is an incredibly good valve and was used as an audio output valve in a couple of makers chassis with very good results. J.

28th Feb 2021, 5:12 pm	#6
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Bush TV22 Mk 1 and 3/4 It is not surprising that later versions of the TV22 employ EF91 valves. The later receivers types TUG 26,TUG34, TUG34A and TUG36, the later being one of the first to incorporate band 3, all sport EF91 valves. They perform just as good as the B9A EF80 and were probably a lot cheaper to buy in considerable bulk from Mullard. Strangely the unscreened EF91 is not provided with an external screening can as is the norm with most receiver chassis. The EF80 is internally screened. The overall gain of the TV22 is fair for what it is but any extra stages of I.F. amplification may have created an instability problem. The EF91 is an incredibly good valve and was used as an audio output valve in a couple of makers chassis with very good results. J.