WTB up to 4 each .047uF 400V Mustard capacitors. Don't care if they are Mullard or Bianchi. I am building a keeper 50watt Hiwatt. Would also entertain 630 volt or a mix either way. I have the 2 PI coupling caps covered.
I would also consider an ERO or Vishay Film too. Thanks. Terry
You want to watch out because there is fake mustard caps being sold everywhere...for very high prices.
"...Cracks are good, it means they're genuine.
The original mylar film has gone soft ( off ), and where that epoxy/paint joins the mylar, the mylar is actually tearing off, what you're seeing is paint/ epoxy with the very ends of the rolled up mylar sheet juuust attached to the paint/epoxy. So what you have going on there is sort of like taking a bite of the end of a rolled up newspaper.
I've pulled these cracked caps apart by folding up on the leads and examined the now broken off ends carefully.
In storage, the leads have been bent a little ,it's that leverage that has pulled the end out and cracked the rolled up mylar..."
2. You are always better off with a higher voltage.
If you are concerned about long life span of parts the capacitors should be rated 30% or more higher voltage, than the actual working circuit.
a. you are always better off with 2 filter caps in series than a single filter cap. This increases the voltage rating and prolongs the life of the filter caps.
3.Where the phase inverter couples to the output tubes:
you are always better off with a 630 volt coupling cap.
Because it's the phase inverter plate voltage + the bias voltage...which often causes these caps to leak and fail.
Add these 2 DC voltages together...that's what the coupling cap has to block.
Plate voltage PLUS bias voltage ! the cap must be rated higher than these 2 voltages added together.
