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Reviewer: Paul Candy
Source: Cairn Fog v2.0 24/192 CD player, Rotel RCD-971 CD player modified with IEC jack to replace captive AC cord, Pro-Ject 1 Xpression turntable w/AT95E cartridge
Preamp/Integrated: Manley Labs Stingray, Pro-Ject Tube Box phono stage
Amp: n/a
Speakers: Meadowlark Kestrel 2
Cables: Audience Maestro interconnects, speaker cables and powerChord AC cables, DH Labs Air Matrix and Revelation interconnects, Q-10 speaker cable, GutWire Power Clef 2, Power Clef SE AC cables
Stands: Premier three-tier, filled with sand
Powerline conditioning: GutWire MaxCon , Blue Circle BC86 MkII Power Line Pillow
Sundry accessories: Pro-Ject Speed Box, Gingko Audio Cloud 11 platforms, Grand Prix Audio APEX footers (under Kestrels), Black Diamond Racing Cones, Walker Audio SST contact enhancer, Audience Auric Illuminator MkII, GutWire Notepads and SoundPads, Duende Criatura Tube Rings, dedicated AC line with Isoclean ICP-002 outlet, homebrew acoustic treatments.
Room size: 13' x 17' x 8'
Review Component Retail: $25

Just when you think there's nothing left to tweak, along comes something else you had never considered before. Ever notice that little 10-cent fuse sitting next to the AC inlet in your equipment? Apparently, some fuses are better than others. They can have a considerable impact on performance. Okay, quit laughing, I am serious. Truth be told, when I was given a handful of Isoclean fuses to try, I laughed, too. However, consider this; did you know that the AC signal entering your components travels through that little fuse first? In some components, it can be several fuses. If upgrading from a stock power cable to a decent aftermarket cord can produce audible benefits, then why not that little fuse?

Last summer, I had the pleasure of playing with Isoclean's power delivery gear and was impressed with the performance and build quality. I wish I could have said the same for the price. It seems Isoclean has addressed every step in the power chain from your service panel to the innards of your power amp and CD player. Canadian Isoclean distributor Barnaby Ng of Quinceton Audio lent me a box of Isoclean fuses to try out. Said fuses are of the slow-blow variety and come in two sizes; 5mm x 20mm and 6mm x 31.8mm. Current ratings for the smaller fuses range from 1A to 10A while the larger ones go from 1A to 15A. Each fuse is 24K gold-plated and each fuse is tested to ensure optimum
performance. Each fuse is marked with an arrow indicating signal flow. Unfortunately, no instructions are provided to determine correct orientation. Frankly, it really was not necessary as it was easy to tell by ear which direction the arrow should point. However, you can determine signal flow with the use of a voltage meter. Unplug power. Remove fuse. Test for continuity between the hot male blade of the AC cord plug and both sides of fuseholder. With no fuse, only one side will be connected. That’s the AC in side. Isoclean fuses are UL, PSE, SA and CE approved.

I replaced the stock inlet fuses on my Manley Labs Stingray amp, Cairn Fog and Rotel RCD-971 CD players with the appropriately rated Isoclean fuse. Some believe higher performance is possible by using a fuse rated higher than the stock one. I chose not to do this strictly for safety reasons. Those fuses and their current ratings are there for a reason and discretion is the better part of valor. If you disregard this, you could void more than just a warranty.

I swapped the Stingray's fuse first and upon powering up, I noted the difference right away, even from a cold start. I noted slightly greater transparency and less hash and grain, not unlike a decent power cable. On my CD players, the effect was inconclusive. I did not notice an improvement let alone a difference in either player. Perhaps they needed a little break-in time? I left the fuses in my equipment for a couple weeks before swapping them out with my original fuses. Whoa. Now it was obvious that the Isoclean fuses had a significant impact on my system's performance. Via the CD players, I observed less grain and hash, greater transparency, a little more detail and a slightly more open soundstage. The effect was not unlike swapping in a set of decent power cables or inserting modest power conditioning. Frankly, my system sounded far less satisfying with the stock fuses compared to after it was isocleaned. I also inserted the fuses in the opposite direction and in all instances, noted increased glare and brightness. As I said earlier, you can easily determine the proper orientation by ear. That may be a good idea if you are uncomfortable working with electricity.

For truly crazy results, I carefully applied a tiny amount of Walker Audio's SST silver contact enhancer to the contact points of the fuse holders. Performance went up beyond expectation yet again.

While spending $25 for a fuse might seem ridiculous, when you hear what these gilded fuses do, you will consider this an outright steal. Most tweaks do make an audible difference but in many cases, not necessarily an improvement. With the Isoclean fuses, you definitely will observe enhanced performance. Highly recommended. Just be careful and don't barbeque yourself.
US distributor's website
Canadian distributor's website