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Old 12th Jul 2018, 6:30 pm   #62
Al (astral highway)
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Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Bach with sparks!

Quote:
Originally Posted by Viewmaster View Post
So, will knock up sometime, a trial full wave voltage doubler to increase EHT to each valve. As current availability is reduced doing this I am getting a 3rd MOT to give it all a shot in the arm....not my arm.

Still awaiting IXDD414CI drivers from China, recommended by, Al.

Running now before I can walk ...…..just created a MIDI file with all the notes on the piano running up the scale on alternate bass/clef. This should eventually show if both sets of sparks can handle it all and what range I should set the converters to.
Hey Albert,

Sounds like you're putting some serious thought and resources of energy and time into this - it's a properly giant project now! I'm just adding up the weight and it must be knocking 20Kg's already.

I hope it all goes the way you imagine it to, and it would be wonderful to see your vision of polyphony realised in the way you describe.

I think if you're going to have two GU81s' like this, each with its own primary and secondary for the RF side of things, they're also better off with individual power supplies that are each properly RF bypassed.

I know it's not something that you're particularly concerned about, but a lot of the available 800W power from each MOT is just heating up your anodes
and with a bit more tuning, even one MOT per valve will be plenty with the EHT from a full-wave doubler. If you're going this route, it's also worth buying decent EHT diodes to make your bridge from.


I think I may have some candidates in my parts box (new, unused) I'll check.
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