MLA

I agree. Built a 360-ish volt version before, so will do a 400V next time. For the record, as good as Dynahi and Dynalo are, the CFA2 is where I plug my dynamic cans in most often. Guess I have a personal preference for current feedback. Or perhaps more adequately, Kevin's current feedback designs are awesome

It is a great amp, fairly independent of price range I think (though 37K obviously is the Best Ever...) When I build mine, I only had it for a couple of weeks and really liked it a lot. Then a friend asked to borrow an e-stat setup so it went to him for further opinion. A month later he declared he’s not giving it back unless I force him to do so. Have to build another one I guess

Well, just checked mine and they are SZ2 - 2253. I purchased them on site in Tokyo in November last year from a music store. They were not in stock at the store, so these were delivered straight from Stax the next day. Unless someone kept yours in storage for a couple of years before selling, I'd assume it's new stock.

Can check mine when I get home. Bought them a little less than a year ago in Tokyo.

So, you are someone who actually needs a preamp To continue your DIY journey, this would be the time to build the KG ubal/bal board (check the thread). Gain of 2 into balanced, but can be set to taste by changing a couple of resistors.

Sören's guide is excellent! Should get you on the right track. Also, I'd suggest checking the status of the BC557; they can handle max 45-50V across, so if the whole circuit has seen 360x 1.414 = 509V while something else is out of place they may be toast...

It's no so much contradictions as the manufacturer specifying thresholds the component is tested to meet under various standards for operation. http://www.ni.com/white-paper/2827/en/ Assuming you're powering your amp from a wall outlet in your house rather than straight from the distribution lines :), I think the 630V rating applies.

I think the Rane note is spot on and you've done that part right. However, since it sounds like the hum travels from left to right channel depending on pot position (though much less audible in the left channel due to high attenuation when pot is at low volume) something else seems amiss. Have you tried either @Laowei's suggestion (amps directly to star ground rather than to PSUs) or first tying PSU grounds together and then use a single connection rather than two from PSU to star ground? Also, I would probably go for pot to either floating as per Laowei or to star ground, rather than amp boards.

I usually attach pot ground to star ground directly. Is that one of the options you already tried? Also, are your inputs tied to star ground as well, or to the pot?

Somehow I knew you were going to say exactly that

Very cool! Which part of the spectrum benefits most?

The DragonFly? You may be in for some device generated problems that may or may not have to do with the power supply: http://archimago.blogspot.se/2017/06/measurements-audioquest-dragonfly-black.html Rather than dropping 200 on an isolator, you might want to try a different device first: http://archimago.blogspot.se/2017/05/measurements-smsl-idea-usb-dac.html That said, some quick cable surgery will probably give you the answers you need right away.

Assuming what you want to do is find out if cutting the computer power line reduces noise, it's just like bomb dismantling in the movies Get two identical USB-cables that meet USB 2.0 standards (assuming audio is focus). Make a small incision in one of them with a sharp knife and cut the red wire. Voila, you now have two identical USB cables exept one does not carry computer power. A/B test away....

^this

Yes, across any of the 2 ohm resistors, that's correct.