I have all Purple except for one M-1 in my P15, replacing a Purple that I moved to my other system.
To me the one M-1 is the icing on the cake. And I like icing. It just gave me a nice little bit of warmth that I had been missing. I think the blend is just right and for now I’m not replacing any more Purples.
But then the question is (if one were to go with the “one M-1” approach), where to put it? PowerPlant? Preamp? DAC? In most systems these are likely all different values, so buying three just to experiment is a pricey proposition. In my case I bought an M-1 for my P20. Did I make the right choice? Who knows? 
But if anyone has a spare Purple 1 or 1.6 amp for my DS DAC, shoot me a PM. I’m using an Orange right now and I’d like to move up. 
Do it one at a time. P-20 first. I have not read one regret of M-1 in a regenerator in omments from the folks that have three M-1s. We second guess ourselves till we go back. My third is in route. The first two replaced a purple and stock fuse where stock fuse in LapS for router and Switch sounded better than Audiophile fuse until M-1 . 3rd will go in another LPS HD Plex 300 powering Digital chain I went slow made a few tuning tweaks to cables but no cable swaps. I am hoping for even more solidity and space to digital images with 3rd fuse. The waittime with multiple M-1s can be many days for break in but not as bad as purple.
I had two purples and one AM Ultimate Premier before, and I almost bought my 3rd Purple when M-1 came out. Now I have three M-1s plus a Purple. But I think many will be happy with two M-1s plus two Purples too.
@vmax, don’t you have two M-1s and Two Purples now? or just one purple? It will be interesting to hear your thoughts if you have two of each now.
I have one purple in my system and one in a box sitting unused. I have a unused LPS and a Yamaha proamp i could place them. I may end up selling them. The are too big for my DS if I blow a M-1 I could run them
It’s sized for a DS? Let me know if you decide to sell! 
In that case the 3rd M-1 will do good things for your system.
Has anyone installed one of these in an Audio Research Reference 2SE, 3 or 3SE? Results? Fuse direction? Thanks!
When I compare again with a Purple fuse to an AM M1 fuse in my BHK pre, the Purple sounded cleaner and M1 sounded fuller. I can live with either one happily. I currently have three M1 and a Purple in system. But 2 and 2 may work better in many systems.
Now I believe a combination of Purple and M1 is better than with one brand throughout. Both sound a lot better than the stocked fuse (I tried it too). In my system after the fuse is changed it takes at least one hour for the sound to come back.
All my purples are gone now so no going back. If I recall correctly the power cord tuning ring does the same clean to full music balance with no system shut down or warm up. I was doing that trick when my Iconoclast UPOCC ICs were being reworked to get more full sound from MogamiGold ICs.
Unlucky for us there are a thousand ways to die and go to heaven in this audiophile obsession.
Fuses, tuning rings, absorbent sheets, sorbothane feet, and many other tweaks bring us closer to audio nirvana.
I am just not there yet. I need to find some real changes like another equipment upgrade. 
My upgraded whisper power cables arrive tomorrow. New amps already. The other night I discovered the ultra low hour amps are hitting a burn in phase. My guess it is the 8 ohm autoformer. Since the other owner used the 4 ohm taps and hardly at all. It is now like a new DS DAC or firmware upgrade or riding the purple fuse burn in roller coaster. Alternating pleasure and punishment. So I turned off DSP and letting frequencies run rampant to put as much current through it as possible.
Don’t forget the punishment that accompanies what you wish for with new equipment.
The irony, for me, is that this burn-in and adjustment phase seems to be greater with lesser components. A new component always sounds better to me out of the box and gets better with time, but with “lesser”components, cables and fuses in particular, you are on a Jekel and Hyde ride for days. Madness.
When doing fuse swaps, I found out an interesting thing. For those of you who use AM M1 fuses, you should try to change direction of fuse to see if you hear improvement.
After my Purple/M1 comparison, I put back M1 fuse in the opposite direction than I had before into PST, I got an instant boost (okay, it takes at least 30 minutes, and more like an hour) in clarity and openness. This tells me the label on the fuse is random because it is in opposite direction from my other two M1 fuses. Even though AM fuses are non-directional supposedly, I heard a significant difference in my system.
I had to rearrange M-1 different than I expect in an LPS that I was using a purple first. I was surprised but seems to be a 1 in 3 labeling differences on M-1 direction based on my experience of 3 samples.
I understand that I might be a little late to the “Fuse Direction” issue and perhaps the subject has changed course what with the M fuse etc.
However its snowing where I live and I have the music playing and I started pondering the issue of which way the SR fuse is best sounding in my BHK Preamp. I am actually interested in purchasing a pair of 12AU7 tubes to improve the sound and sort of stumbled onto the fuse thread.
Anyway, my system has all blue fuses except for the Preamp. I was wiggling the power plug and blew the blue fuse. So I thought I would try the purple.
I maybe have 800 plus hours on it.
After reading this thread it got me thinking about which direction I initially put the fuse in and had a look. I also did some critical listing as well to both directions.
I understand after reading the thread there are folks on both sides of the isle.
For me I felt compelled to share that my initial installation sounds the best in my system.
In the reverse direction I quickly noticed a dulling and muffling of the sound.
It seems like the transparency has diminished.
It was rather noticeable.
As the picture shows, for me the fuse (SR) text should read from left to right with the ‘S’ closest to the Preamp and the ‘R’ closest to the cap.
Again, I encourage you to try it both ways but for me it is undeniable sonically-speaking as the picture shows which is the proper way to insert the fuse.
It was also the same with the Blue fuses as well. Sorry to be so long winded but I wanted to give some back ground to the subject and report what I found.
Cheers, Ian/sandrock
That would be correct as the fuse holder has the power from the cord connected to the inside of the fuse holder and the circuits connected to the cap size.
I have a Purple in BHK pre and just added another in DS Mk2, and I also have SR M-1 in PST and P15. These two pairs brought great balance, and my system never sounded better.
Confirming fuse directionality by sight would assume the manufacturer intentionally make a directional fuse and that the putting on of the label reflects that desired direction. I believe that SR’s website says there may be a sonic difference in the direction you have it but it is up too your ears, unspecified by them. I have them in the opposite direction as shown above. Go figure.
I also have it the opposite direction as shown above. The current flows from the back of the unit to the front which means from the cap end to the other end. I find that sounds clearer than the other way around.
