I have had SR purples in my Primaluna pre and power for a couple of years and loved them, but it took about 20 hours of play to really start to hear what they were doing. At 50 hours the juice really started to come on.
A few weeks ago I added the SR "Master" fuse to my Holo Audio May Level 3 Kitsune DAC. The Holo May came with a "Nano Red" fuse which claimed audiophile level enhancement. The pricey Master fuse had a 30 day trial period, so I thought, "why not?" This fuse takes somewhat longer to break in than the Purples, but it has been worth the wait. There is more "solidity" and tonal accuracy along with sound stage enhancement with an increase in detail - clearer sustain and decay - all the goodies. The Master was played as much as I could within the 30 day trial period. At first the fuse sounded a bit stiff and flat footed, but then opened up after about 20 hours. Now after about 200 hours it has bloomed extraordinarily. Again, make sure you take the time to play it as much as possible within the 30-day window.
These are being played through Cornwall 4 horn speakers, and it may be that high sensitivity speakers show these fuses off better,