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Pieter H · 27th Nov 2017, 10:52 pm

Hi Synchrodyne,
thanks for the nice feedback!

As to the analysis of the Philips and Mullard approach, I think you are largely right. Up to the end of the 1950s the outward approach was very valve-centric. The successive generations of valves were always first introduced in the Philips tuners and/or TV sets, and then quickly afterwards announced on the market by the Electron Valves Division (HIG Elektronenbuizen), and its Valvo and Mullard brands. However, the fact that tuners received an official family product code (AT or NT followed by 4 numbers) next to their internal factory code, indicates they were avaialbe for external delivery. Reference designs of tuners were published to support the design-in of the valves, but it seems that actual third party sales of tuners was very limited. And if so it was mostly to companies affiliated with Philips, e.g. Kriesler in Australia from 1957 onwards and CBRT in Brugge, Belgium, which produced TV sets based on Philips reference designs for different brands. The only sale of a tuner to a "competitor" is in 1960 to Siemens, but as far as I can see only one set.

But around this time there has apparently been the decision to start offering complete tuners to the external market, which happened under the Philips, Valvo and Mullard brand names. At this time Valvo published a booklet promoting the AT7630 family of VHF tuners and AT6320 UHF tuners. Although this was more or less co-incidental with the introduction of UHF I doubt that was the reason. Personally I think it was more based on expansion ambitions, and/or the need to provide more load for the factories for higher cost efficiencies.

I think there is now sufficient evidence that Mullard stuck with the remote cut-off concept and the associated valves PCC84-->PCC89-->PCC189 for the positive modulation UK standard, while the continental tuners used the sharp cut-off PCC84-->PCC88 for the CCIR-B/G. But please note that the French and Belgium standards, although also based on positive video modulation like the British standard, employed the same sharp cut-off concepts as the standard continental tuners! With the PCC189 variable-mu triodes the continental tuners didn't move to remote cut-off (the gain control remained unchanged) but the valve improved the cross-modulation behaviour. From that moment onwards - around 1963 - all Philips tuners used the same valves again.

So yes, it seems the PCC89 was developed specifically for the UK tuners of Mullard, but that by itself was not exceptional. Nevertheless its use was only a fraction of the widely used PCC88 and 189's. I agree with you that Mullard developed its AGC concept before the PCC89, in fact it was largely introduced with the PCC84 from the beginning and continued with the improved PCC89.

Thanks for your inputs and analysis, it has definitely helped me to get the story clearer!

Cheers, Pieter

27th Nov 2017, 10:52 pm	#18
Pieter H Tetrode Join Date: Sep 2017 Location: Waalre, Netherlands Posts: 67	Re: Introduction PCC189 in Mullard tuners? Hi Synchrodyne, thanks for the nice feedback! As to the analysis of the Philips and Mullard approach, I think you are largely right. Up to the end of the 1950s the outward approach was very valve-centric. The successive generations of valves were always first introduced in the Philips tuners and/or TV sets, and then quickly afterwards announced on the market by the Electron Valves Division (HIG Elektronenbuizen), and its Valvo and Mullard brands. However, the fact that tuners received an official family product code (AT or NT followed by 4 numbers) next to their internal factory code, indicates they were avaialbe for external delivery. Reference designs of tuners were published to support the design-in of the valves, but it seems that actual third party sales of tuners was very limited. And if so it was mostly to companies affiliated with Philips, e.g. Kriesler in Australia from 1957 onwards and CBRT in Brugge, Belgium, which produced TV sets based on Philips reference designs for different brands. The only sale of a tuner to a "competitor" is in 1960 to Siemens, but as far as I can see only one set. But around this time there has apparently been the decision to start offering complete tuners to the external market, which happened under the Philips, Valvo and Mullard brand names. At this time Valvo published a booklet promoting the AT7630 family of VHF tuners and AT6320 UHF tuners. Although this was more or less co-incidental with the introduction of UHF I doubt that was the reason. Personally I think it was more based on expansion ambitions, and/or the need to provide more load for the factories for higher cost efficiencies. I think there is now sufficient evidence that Mullard stuck with the remote cut-off concept and the associated valves PCC84-->PCC89-->PCC189 for the positive modulation UK standard, while the continental tuners used the sharp cut-off PCC84-->PCC88 for the CCIR-B/G. But please note that the French and Belgium standards, although also based on positive video modulation like the British standard, employed the same sharp cut-off concepts as the standard continental tuners! With the PCC189 variable-mu triodes the continental tuners didn't move to remote cut-off (the gain control remained unchanged) but the valve improved the cross-modulation behaviour. From that moment onwards - around 1963 - all Philips tuners used the same valves again. So yes, it seems the PCC89 was developed specifically for the UK tuners of Mullard, but that by itself was not exceptional. Nevertheless its use was only a fraction of the widely used PCC88 and 189's. I agree with you that Mullard developed its AGC concept before the PCC89, in fact it was largely introduced with the PCC84 from the beginning and continued with the improved PCC89. Thanks for your inputs and analysis, it has definitely helped me to get the story clearer! Cheers, Pieter