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Hullo Tracey and the Group, Does anyone chat about with Ian, GM3SEK? He's a member of the Oxford University Radio club, and still active on VHF, I believe. Perhaps he might "Pass along the ball" to

RE: GM3SEK Tetrode Controller Somewhere in the collection of 50 some years of building amplifiers there exists a new, pristine collection of Tetrode Controller stuff. There are two boards, unpopulated

Is there a reason why we couldn't do a run of these, if G3SEK doesn't want to produce them (looking at the website, looks like it was last updated in 2020)? I have one of these I purchased a very long

I have a complete, unbuilt WD7S Triode Kit, which I'm never going to use. See https://silo.tips/download/the-wd7s-triode-control-board I would entertain the thought of selling it if it is of interest

With ZERO bias, and using the SSB position,? you will end up with .220 x 2600 vdc = 572 watts, which will make both tubes go cherry red. JI's method uses a small lab typ supply, like my 0-30 vdc @ 3

Thanks for the link. I was thinking more than what it sold for.

Yes, but board was in Portugal. https://www.ebay.co.uk/itm/116441758244?_skw=116441758244

Still can't find it? Is this a European Ebay?

This listing sold on Thu, 9 Jan at 4:18 PM GMT ...

Must be on the European Ebay? Does not show up on mine.

These are now as rare as hen's teeth, so I thought that I'd flag it to the list in case anybody is interested. I have no connection with the seller. See eBay Item No. 116441758244 73s Tracey G5VU

The old man who sold it to me is reliable. The PA has hardly worked but it has not been turned on for about ten years. I will at least regenerate, a little, the filter capacitors, one by one, with an

I'm not very familiar with the L7 Francois but if I guess you could do two tubes at once. Even if you just turn on the amplifier and key it, at full plate volts, if you think the tubes are OK. Run it

See https://www.w8ji.com/gettering_tubes_al572b_al80b.htm Thanks for this very interesting post. It should definitely be adapted to a 3-500ZG (graphite anode) because the photograph shows a 3-500Z

Yes. Very true but I' had it where the tubes will flashover at 1900/2000V, so by changing the HV output wires on amps like the AL-80B and TL-922, you can easily get to around 1000V to start the

He can also just use the low 1900 vdc CW position, apply a bit of drive, and tune the amp a bit off resonance.? ?That will get the tubes good and red. A good Eimac 3-500Z? will? hi-pot? 16 kv?

Francois...... Eimac and the other makers of the 3-500Z? used this chemical, called? 'Zirconium'? ?on the anodes.? ?The Zirconium coated anode IS the getter.? It is heat activated when the tube

Hi Francois. Running the tubes on filament only does not help at all. You must apply drive to activate the gettering process. See https://www.w8ji.com/gettering_tubes_al572b_al80b.htm That is a good

Thank you for this very important information. The PA has not been used for 10 years. So there is no point in heating the filaments for only 1 or 2 days to hope to degas. I need to heat the anodes. I

If you run 500W PEP only, your tubes will quickly become gassy. They have no separate getters. The gettering is done by the anodes and so they must become red during operation to keep them healthy.