The amp ships with the new Mullard's and they are dependable even though they "sing" way too much for my tastes. One of my other Blue Hawaii's that's been on loan for well over a year has the new Mullard's and with zero issues despite heavy use.
As for the XF2's, any tube can prematurely fail but the set in my BHSE has been in some Blue Hawaii here for almost 10 years and I bought it slightly used. These are pretty much bullet proof...
I'm talking about the bog standard EL34 from JJ too. The blue (and red glass) version is supposed to be identical.
In a "normal" tube amp you have the signal entering on the grid with the cathode and anode loaded with resistors or chokes. If the tube shorts then too much current is passed and the resistors burn up. None of that applies here...
Personally I'd never use a Shuguang tube in any of my gear. Hell I'd rather use my "made in USSR" tubes instead...
Good question. Not sure what happened to this one but the heater died so I'm guessing it shorted to the cathode as the mosfets all lost their magic smoke.
I never had any problems with my 10+ year old SED's but something might be off with the more recent production. The JJ's are excellent and the new production Mullard's seem to be solid as well.
The real "problem" with the BH circuit is that tube failure can be very bad news indeed.
Metcal has something similar in the newer stations, sort of a stand-by feature when the wand sits in the stand. I simply removed the magnets so it doesn't do that any more.
Yes and it is not subtle. One cool thing, when you solder LED's they light up...
The difference in power is not something I've ever noticed, even with them side by side.
Anything from the PS900 should be interchangeable as they are pretty much the same device, albeit the 900 has a much nice chassis (die cast). The chisel tips are what I use most of the time though I have pretty much every one they make. SFV-CH25AR is what I've been using for the last few months....
Pretty much any film cap would work but it's that big as the cheapest caps are often 250V or so and also much more common. This was just lifted wholesale from the KGSSHV board.
No board run coming from us but any of you are free to organize one.
There would be a lot of wires running between the boards but yeah, it would be possible. Also, it isn't 100% clear from the pic but next to the heater connector there is a hole in the board to pass the wires through.