Got home form my New Year break in the Highlands of Scotland last night so had a spare day today
I think I'm done!!!!!
I've not put an FET board in and just added a 33k grid stopper alongside the 22k of the normal. Doubt I'll hear a difference but thought it was worth a shot.
I wonder if I'll keep my 100% record of OT primaries being the wrong way round?
Going to do some checking before I tentatively fire her up tomorrow.
If anyone spots anything let me know.
Still can't seem to build as pretty as some of you guys.
what's the deal with the ground switch? I've wired it in but not sure what it's for and how to use it.
Marcus
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Looking good Marcus! I can still find the (old) standard incandescent bulbs, but if that gets tough I think the specialty types for chandeliers and sconces will persist for a while. They are available in 60W.
As you can see in the schematic the ground switch connects a cap from one mains line or the other to ground, with the idea being that you could get rid of some EMI noise with the switch one way or the other. The cap should really be a Type X2/Y2 (fails open) to be safe. You can see if it makes any difference, but a line filter IEC might be a better option.
Last edited by martin manning on Wed Jan 04, 2017 8:54 pm, edited 1 time in total.
If your switch has a center-off position then the cap is out of the picture, but many people just don't install the cap. Being a 600V running at around half that p-p voltage it is pretty safe, but doesn't meet modern standards. Below is a more modern version of a simple cheap EMI filter.
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The plate voltage has dropped from 445vDC to 320vDC so something's wrong!!
Any ideas?
marcus
p.s.
schoolboy errors again. I wired the valves as per the original layout but then added the 1r resistors for the bias. you can't do that with the 1.5k resistor across to pin 1 as it will short out both of the bias feeds........
I've removed one end from pin 1 and flown the resistor and attached the bias connections to the resistor then to pin 5 instead of pin 1 as shown on the layout.
