Henceforth to be abbreviated as "g-slug", the Graphene Sluggo from Vera-Fi Audio is getting its own review from me because a few sentences in existing discussions won’t satisfy my desire to fully share my thoughts about these. I feel ready to write, as the last two g-slugs I bought have about 20 hours on them, and the initial four have about 50-60 hours on them. I feel confident enough now to expound. These g-slugs are fascinating creatures; they are not your friendly neighborhood slugs.
For info on the prerequisite purchase needed to use g-slugs, see my review of the companion product, the Swiss Digital Fuse Box (HERE). (There’s an option to choose a g-slug for an upcharge on any SDFB purchase, and currently, SDFB owners get a 20% discount for upgrading.) If you don’t know what a SDFB is, my review was pretty in-depth and should give you most of the info you’d require. I’m a bonafide slug connoisseur with 13 slugs in my digital music streaming system. Yes, THIRTEEN, and soon to be fourteen when a new component arrives! Some devices have more than one slug, and I have them in subwoofers, external power supplies, everything I can manage because sonically it affects each device. Slugs replace fuses in your components’ fuse holders and SDFB is a non-sacrificial overcurrent protection device installed upstream from the fuse holder inline with alternating current. The SDFB is the key to slug town.
I’ll start at the end by getting to the point now, then walk through some details and my recommendations. G-slugs are better than other slugs. They are solid copper cylinders the size of standard fuses that have vacuum deposited graphene on the surface -- and its a thick, solid matte black coating with no etchings on the surface.
If you just want the gist, g-slugs make any device with a fuse holder (and a SDFB upstream) produce more linear, extended frequency response that constructs a soundstage and its sonic images with greater precision and dimensionality than you currently experience 
. They bring you one step closer to 3-dimensional life-like music reproduction and help vanquish speaker locations, perceived room boundaries, and obstacles to musical immersion... your worst enemies!
Okay, first thought: Solid copper slugs sound better than fuses and reduce resistance between fuse holder endpoints drastically... to almost zero, right? Is that all that matters? If that were so, then everyone would use humongous 6 awg copper conductors for all cables to get really low resistance. The reality is that there are many other aspects of the power conduction chain, like dielectric properties, crystal barriers, and a bunch of other properties of various materials, their shapes and surfaces, construction geometries, etc, that result in various sonic consequences. Most of the slugs I had been using were solid copper and I chose to hand-sand and polish the surfaces to a mirror finish and clean them carefully in order to extract the finest high-frequency details (yes, this is effective in resolving systems), which is related to the well-known "skin effect" of conductors. Yet, a graphene-coated surface dramatically outperforms my best attempts at solid copper slug surface modifications.
To get the point across, here’s a hypothetical numerical rating scale of 1-10 with my best estimates to compare sonics of the different options I’ve tried inside fuse holders:
If a stock fuse with a tiny resistive wire is a 1 and sounds the worst, then:
- a custom fuse with crystals, high voltage treatments, etc, is a 2 or maybe 3,
- brass slug is a 4,
- copper slug with original machining surface ridges and an engravings is a 5,
- copper slug with a mirror-finshed polished surface is a 6,
- g-slug is a straight 10.
Before g-slugs, my whole system was filled with mirror-finish copper slugs, which are all much better sounding than fuses, except my subwoofer amps, which have gold-plated copper slugs. Here’s what I experienced...
Firstly, two large sized g-slugs went into the amp. WHOA. When you first install these, it’s very energetic feeling like you are very close to the performance stage due to the inrush of newfound detail retrieval and emphasis on mids and low treble. I have experience using the top capacitors from Duelund, Jupiter, and V-Cap, and this initial experience is similar to using V-Cap CuTF caps by themselves. It’s like viewing the soundstage with a fish-eye magnifiying glass, which is interesting and highly resolving of details within that particular viewpoint, but it isn’t natural or a linear response. The copper in the slugs gives it the appropriately warm midrange similar to the copper in the CuTF caps, and the graphene enhances the top end. But, I found that g-slugs require about 4-6 hours of burn-in to relax, open up, and evenly express resolution across the audible frequency range and up into the very high frequencies, beyond what your components normally output.
In comparison, the best combination of linear and extended frequency expression that I’ve found in the world of capacitors is the relatively new Jupiter COMET silver foil. Using these by themselves or as a bypass cap in combination with the top V-cap or Duelund caps can be stunningly gorgeous, detailed, and realistic. Yet, they still can’t quite transform the listening experience like what the graphene coating on a g-slug does, which is like uncorking latent resolution and frequency extention, particularly beyond 10-12khz for exceptional spatiousness and realism. It brings out more spatial information that informs your mind of the implied locations of sounds within the soundstage. It also gives you more complex sonic textures, more defined images, and a more even and filled-out sonic picture.
When I was doing testing recently, I took all of the g-slugs out and went back to all polished copper slugs in non-subwoofer components. There was still a lot of details with the copper slugs, but immediately I noticed that the the sound stage flattened out in depth and my speaker locations were revealed with the particular recording I was listening to. I had forgotten how non-existent the speakers had become within the room when the g-slugs were installed. The front wall of my listening room had also previously disappeared, but now seemed to be a containment boundary. There was a loss of space/air in all directions with an obvious roll-off in high frequencies and the sound quality took on a quality that I can only describe as "stylized", as opposed to what was previously effortlessly natural. This is hard to describe, but it was like a more artificial sound quality, and the experience was more like listening to a recording of music or the reflection of a live performance off of a wall instead of a live performance itself. It was no longer a natural, linear frequency response, so the perceived realism suffered. Admittedly, I was a little shocked that I had forgetten how I had previously experienced music in the same room only a couple weeks prior.
I began progressively adding back the g-slugs to my components, and what unfolded with each successive addition were greater overall resolution, more evident spatial relationships and image location stability, a sense of space and transparency, and also a feeling of immersion into the musical experience and my satisfaction with it. These g-slugs have some real magic about them, and that’s why I’m writing this. Lastly, I think the contrast between silence and sonic substance widens, so it *seems* like there’s a "blacker background" from which the sounds arise from, but I think it’s actually about your components simply producing more sonic information to build a more convincing sonic scene than it is about removing interfering low-level noise. I think there’s something about the super-conductivity of the thick graphene coating that is more than a noise-filtering application.
In order of highest to lowest impact in components I installed g-slugs in:
1) upgrading from polished copper slugs to g-slugs in the amp had the largest effect, then
2) DAC
3) preamp, tied with the streamer’s external power supply
4) Farad Super3 linear power supplies for modem and Fidelizer router separates. Effect here was minimal, so I’m using the copper slugs in them.
My recommendation is to put a g-slug(s) in your amp. If you don’t like it, ummm, I would be shocked. If you have a DAC, do that too. I think a good goal would be to make approx 50% of your slugs g-slugs, and use slugs with a very smooth polished or plated surface in your other components. If you put g-slugs in ALL of your components that use IEC fuses, then you may end up with a need to balance tonality because of the additional top end energy, but for me, that’s not a problem because I have 101 ways to accomplish that balancing act, from power cable connectors, to which components they are powering, to capacitor combos connected to ground planes, to modifying acoustical treatments, etc. In other words, the things that you previously used to boost high frequencies may become obsolete. Overall, tonality of the g-slugs is really excellent and I'm using a lot of g-slugs to gain all the extra resolution I can. They extend all the way in both directions, and give you meat and bones and body... and the beauty of the finest airy details, too.
I feel justified in my enthusiasm about g-slugs after they’ve burned in for awhile. They are transformative in a way that is similar to going from a stock fuse to a SDFB with a copper slug. If you want a higher resolution sound system, g-slugs. If you go from a stock fuse and zero SDFB’s in your system straight to a SDFB and a g-slug on your amp(s), please leave your comments here for me to read! :)
