The G6 is no slouch.

No worries, you are welcome. The EF400 is about equal on all of its outputs but there is a very slight magic kiss from the balanced outs. I typically use XLR but will sometimes do 4.4mm. As far as input, I use the USB B input as I have a pretty decent cable. Haven't tried the USB C input yet but pretty slick that it is an option.

XS sounds beautiful on the EF400.

What I am using to represent the ESS side right now is a Topping D10s DAC paired with a Schiit Asgard 3 amp which tilts towards the warmer side but power wise, is a fairly close-ish match to the amp in the EF400.

The XS sounds more enjoyable on the EF400. At the end of the day is the differences worth upgrading, debatable. The ESS still sounds good with it, just not MY favorite with the XS and others might not feel the difference is worth paying out $$$ for.

With that said you need to figure out other things to justify spending the $$$ over your current K5Pro.

Basically some of the pro's:

+ Sound is subjectively better with the XS on the EF400 to my ears

+ Lots of headphone outputs, XLR, 4.4mm, 6.5mm and 3.5mm all on one unit. This can open a lot of doors for cables options and lets you use balanced cables.

+ Has basically two DACs in one, the NOS and OS. OS would be more similar to a AKM chip, which would be kind of a refinement. Sometimes it is hard to tell the difference, if at all.

+ More power at your disposal compared to the K5 Pro which can be helpful for harder to drive headphones to unlock their potential.

Sorry for the wall of text.

The Himalaya R2R sounds more natural and full to me. This usually pairs well with my Hifiman headphones that are bright and detailed to even things out. The ESS dacs sound a little more bright and detailed which pairs well with a lot of my Sennheiser headphones which for my ears could do with a bit more brightness and detail.

I had my in/outs mixed up, *le sigh*, clearly was still asleep but my coffee def fixed that! I corrected my comment and clarified as headphone outputs.

This is a no frills all in one combo and there are no inputs, just outs.

As you have had a chance to listen to it, it is really up to you. As an owner of an EF400 and many other amps, dacs and combos, it is one of my favorites for many reasons which includes the way it sounds and many headphone output options it has for convenience, it pretty much does it all! It is also a real pain in the ass to find an R2R DAC at a budget price (even if the Himalaya isn't the best, still R2R!). The EF400 is a powerhouse that can comfortably drive whatever you throw at it and is also great with IEMs.

So if you like the way it sounds with your XS, have the budget to scoop up one without scraping by, it's really not a bad purchase but make sure to feed it to a good power source as a poor one can cause pops and other unwanted sounds from the R2R NOS options.

You would probably want to discuss this with your doctor.

- I can't imagine using in ears for 8-10 hours out of the day, assuming you even let your ears have some time to rest and 'breath' during that time.

- 56db/60db is perfectly fine, I don't think volume is your problem.

- If you are going to have that long of sessions and are running into these problems, maybe try switching to a lightweight headphone that is compatible with your iOS device to give your inner ears a break while you sort out whatever issue you are having or sit down with your doctor.

I scooped one up a few months ago, it's pretty awesome and I love it.