Transformers are a true art form.

There are two different caps on each side. I wouldn’t use a .47 in place of the .22.

Close to what is in there. I think .22 and ,47uf is what I used. 600 volt. With Duelunds it is a very tight fit.

I don't know if I am the only one. The stock caps are fine but I like Duelund caps. It sounds very good, with a natural hall sound, tight bass and excellent depth and width.

Then something to do with the adapter. What, I don't know. I know that apple doesn't use OTG, from what I have read.

Do the cables work without the adapter? I would check that.

Use the ceramic sand filled fuses, (The amp uses slow blow) as they sound better IMO. And the cost is not exorbitant. There are ceramic (non glass) that are not sand filled so make sure they are. The sand stops any arcing after the fuse is blown but I get them because the sand also dampens the...

Yes, they can fail over time. The endure current inrush over and over and will finally give out. This is not abnormal. You can put in a bigger fuse (don't) but then you don't have the safety of the fuse if a tube blows or some other part of the circuit, so never do this. Also, there are sensing...

In the back on the PS by the power cord connection. Do you have the manual? Some power supplies are fine without a load and some not. I don't know about the PS for the 300B MKII. I am sure someone here does know.

There is room up and down the price chain if the quality is there, which Cayin is proving capable of.

I think so but I would not call the mids lush. They are honest and not overripe. You get the more lush mids with the WM1Z but I also think it obscures some of the detail and quality of the recording.

Exactly. They to breath some.

The WM1Z is warmer sounding. The Elite is more transparent, with better separation and depth. Also l like the bass line on the Elite more and detail.

If the tubes have any noise the Utopia are going to reveal it as do the iBasso SR3 headphones. The SR3 are excellent headphones and I use them much of the time with the 300BMKII with Whiplash cables. But if tubes have noise, they will pick it up. I have the Chinese metal base and they are...

I like the small perforated. I still choose it over many headphones I have and consider the SR3 one of the best headphones on the market regardless of price and very comfortable to wear.