Is it normal for there to be a "pop" sound in the drivers when turning on the amp with headphones connected? It seems to happen w/ the IE80s (16ohm), sometimes that sound can be really loud if I have them in my ears when turning on the amp. Haven't paid attention or noticed it yet with the HD650s (300ohm) though, maybe I should see if it happens with it too... all single-ended right now btw.
Hope that pop isn't damaging the drivers or anything. Other than that, hm... slowly getting used to my new Rx MK3-B+. It's weird, a lot more "clinical" sounding than my old SR-71 (doesn't have that low-mid end warmth on the SR-71), and is a lot more detailed instead... in fact, I find the low-mid range to be quite a bit more detailed on the Rx MK3-B+ so far when compared to the SR-71.
When I first got the amp, I wasn't too impressed tbqh... but after the past few days of burn-in, it seems to be slowly "getting there", and I'm actually quite impressed with its accuracy and detail. Only using single-ended (backend) right now... waiting on some balanced cables right now, but still considering maybe getting a temp balanced IC from TTVJ (either the ALO or CablePro one) and try to balance the amp's backend at least to see if it would provide more power/clarity/mW/etc for my (currently) single-ended HD650s (waiting on a balanced cable for them too.)
The amp does have its minor quirks (as mentioned), but so far I like it for the most part. Quite an "upgrade" from the SR-71, although the SR-71 is pretty good at what it does (a "warmer" amp sound-signature) too. There is background hiss with my IE80s (16ohm), even on low-gain, but it seems to be tolerable for the most part... hoping maybe going balanced eventually will help a bit. But yeah, the noise-floor isn't totally "black"/quiet as it is with my other amps.