Thanks for the congratulations and your thoughtful post. I have been lurking this website for years and always enjoy reading your posts.
Not sure what was going on with having to ground the output RCA’s on the iPhono2, but it was indeed weird. I agree as per your explanation, it shouldn’t be the case, but maybe something in the iPhono2 was not connected properly, or maybe it was because the provided power supply is only a 2-prong power supply without a ground prong. Either way, connecting the turntable’s phono cable ground wire to the iPhono2’s ground post did nothing, and when I tried grounding the iPhono2’s ground post to a real ground it actually made it worse. I was out of ideas and was ready to return the product, but before doing that I decided to open a ticket with iFi and see if they can figure it out. iFi said it’s almost definitely a missing ground somewhere. I had the iPhono2 hooked up to an ADC, and the ADC was connected to a computer with an optical cable. iFi thought it was because I was using an optical cable going from my ADC to the computer, which has no ground, and they recommended using a coax, so I tried that and the hum was still there.
In my attempts to diagnose the hum, I took the ADC completely out of the chain and connected a pair of headphones directly to the iPhono2’s outputs, and the hum was still there. It was only when I accidentally touched a real ground off the output RCA’s that it finally went silent.
What you say about the iPhono2 needing a fuse to sound its best seems a bit unfair at face value, to be honest. You could say that about any tweak for any turntable, amp, anything. My turntable doesn’t need the expensive mat I’m using, but it sounds better with it. My amp sounds better with a nice powercord than a cheap one. It’s not fair to single out the iPhono for this. Besides, the iPhono2 itself doesn’t take a fuse. It’s the linear power supply (that iFi doesn’t recommend using) that takes a fuse. We’re talking about tweaks here.
As for the "quantum" thing, I completely understand the reluctance to buy into something with "quantum" in the name (except the TV show Quantum Leap, which rules). I have always been a skeptic and cannot stand the pseudoscience that various new-agers are always putting forward, laden with "sciencey"-sounding buzzwords like Quantum.
There was another audiogon forum where a user said something similar - they were intrigued by the SR Black fuses, but they had reservations about Synergistic Research based on a strong disagreement with the company’s philosophy. In a previous life, I also would have immediately dismissed anything with Quantum in the name, quickly laughed, assumed charlatanism and placebo was at work, and moved on.
But I only pulled the trigger on this product after reading the many testimonies on various audio forums, including several threads on audiogon. I wasn’t even a believer in fuses until a few months ago. It’s interesting that even people who believe in audio cables, power cords, power conditioners, are still reluctant to consider fuses. We all have that line where it’s like "ok, this is too much". Fuses are probably the most easily dismissed, yet significant tweak out there. After experiencing the improvement the AMR fuse made, I got curious and read at least a dozen forums, specifically searching for posts from users who have experience with multiple fuses. No one really praised the AMR that much, a couple of people said it was good and had lush midrange, but the couple of people who had both the AMR’s and the SR Blacks couldn’t stop talking about how good SR Blacks were. The guy I bought my Blacks from is an amp maker, and he had various high end fuses for sale, from AMR to Furutech to Isoclean, and his opinion was the same as what I had read on many forums - the SR Blacks are not just a little better than the other fuses, they are a lot better. Having scoured many discussions about the SR Blacks, I have personally never seen a post by somebody who tried the SR Black fuse and was not absolutely astonished by it. Even Synergistic Research puts their money where their mouth is and offers a 30 day trial with a full refund to anyone who is not satisfied, and to my knowledge, no one ever sends these things back. Mine were used, on a very good deal, and I knew that if I didn’t hear a difference or didn’t think it was worth the money, I could sell them for the same price that I bought them, so there was really no risk.
I completely understand the reservation of supporting a company that one feels perpetuates pseudoscience with the terminology they use, but that’s more of a political decision than an epistemic one, and I’m personally not as invested in "identifying" as a skeptic and punishing companies for supporting pseudosciencey language as I used to be (and I totally used to be that guy). I’m just interested in what’s true. If these SR Blacks transform your system as much as people say, or if it’s all just hype, I wanted to know. So, for me, this exercise was not about which companies I support and which ones I don’t, or voting with my wallet. I was just blown away by the difference the AMR fuses made, and I wanted to see what else was possible. The SR Blacks were the most hyped fuses out there, and I could try them without financial risk, and curiosity got the better of me.
While I am still an extremely skeptical person, most of the "audio skeptics" I come across reading online forums are mind-readers who assume they know the inner-workings of everyone else’s mind. They act convinced that everyone they disagree with is fooling themselves or is under the spell of the placebo effect, and this goes not just to fuses but to power cables, interconnects, speaker cables, everything. I started out being one of these people, but I’ve been surprised way too many times in this hobby to ever again dismiss something a priori. At one point I believed cables made no difference, and eventually I heard the difference myself. The same thing happened with my belief in digital cables, power cords, and most recently fuses. So while I am still very skeptical and science minded these days, I want to at least check for myself.