Synergistic Red Fuse ...

Just changed out the Reds to Blacks in my Cambridge 851C. I have roughly 72 hours on them and definitely an improvement over the Reds. Playing with direction of the fuses now and one I definitely had in the wrong direction. 

I started with a Black in my ModWright LS 36.5 and because I have two in the Cambridge I thought I'd save a few dollars and start with the Reds there. The Reds were definitely an improvement over the stock fuses but just didn't feel the change was a drastic as the Black in my ModWright. Bought all fuses from VH Audio and of course I was able to send the Reds back for the Blacks which was nice. Anyone thinking of trying the Reds first I wouldn't bother for the price difference honestly. 

Everything has improved across the board but the big thing I can say about these fuses is I find I enjoy listening to the volume down a little now which means my amp is running in Class A more which is nice as well. Too bad my Pass amp doesn't have fuses instead of the circuit breaker switch on the back they use; I suspect it's of decent quality.

"Has anyone tried a SR Red Fuse in a Audio Research Reference 10?"

I have recently sub'd in an Black in place of the incumbent Red that had approx 60 hours on the clock in the Ref10, straight out of the box evolution across the board over the Red.

Thinking of Synergistic blacks for my ARC Ref 150 and Ref 40 and I see that there are a number of ARC owners who have installed the Blacks in their gear notwithstanding my 2 concerns.
1-The Ref 40 uses a 6amp fuse and the Ref150 uses a 7amp fuse. The Synergistics make neither so I would presumably have to come up short but as close as possible (a 5 and 6.3, or if I'm adventurous, two 6.3s).
2-I believe both fuses are specified as 250v whereas the Synergistics are 500v.
Not an electrical engineer or even an electrician so I do not generally like ignoring manufacturer's choices unless I know that it can cause no harm (e.g. after market power cords).  

blu....You should be looking at the 5 X 20mm Slo Blo fuses which are 250V.

Personally I would tend to err on the side of caution, with a fuse slightly under rather than over the manufacturers rating where possible.
Should you consider a value over e.g an 8 iin place of the factory 7 I would recommend a Fast Blo , 

Gpgr4blu, I’m sure Tsushima1 is correct about the physical size and voltage rating of the fuses that are required for your ARC gear, but to clarify about the voltage ratings: The 500v and 250v ratings refer to how much voltage a fuse can withstand when it blows. The voltage a fuse will "see" when it blows (i.e., the voltage that will appear between the fuse’s two contacts) will be the full line voltage. So the higher that rating is the better, everything else being equal. Under normal operating conditions the voltage appearing across fuses having these kinds of ratings will be a very miniscule fraction of a volt. And when the component is turned off the voltage appearing across the fuse will be zero.

HOWEVER, I would disagree with a couple of important things that have been said just above:

1)I would strongly recommend against substituting a fast blow fuse of somewhat higher current rating for a slow blow fuse of somewhat lower current rating. Some time ago, in connection with this thread, I looked at the detailed "melting point" specifications that are provided by the major manufacturers of garden variety fuses. That spec defines the approximate combination of current and time that will cause the fuse to blow (actually, in terms of current squared x time, which is proportional to energy). The upshot is that such a substitution stands an excellent chance of causing the fuse to blow almost immediately. Especially in the case of a mains fuse, where brief but very large "inrush currents" may occur at turn-on.

2)Earlier in the thread there were multiple anecdotal indications that the unspecified melting points of SR fuses are probably a bit lower than those of garden variety fuses having the same current rating (i.e., indications that the SRs blow a bit more readily). And it would seem expectable that in general a fault in a component that would cause a fuse to blow is more likely than not to result in a very large current increase, rather than one that is just slightly greater than the rating of the original fuse. Especially in the case of a mains fuse. So for both of those reasons I would suggest using a 6.3A slow blow in a 6A slow blow application, and an 8A slow blow in a 7A slow blow application. And likewise if an SR fast blow is substituted for a stock fast blow.

Good luck. Regards,
-- Al