Swiss Digital Fuse Box - "What headroom sounds like"
Swiss Digital Fuse Box (SDFB) is non-sacrificial overcurrent protection device that serves as a replacement for fuses in audio equipment.
There are four devices in my sound system that I’ve replaced fuses with the SDFB, and its transformative capacity to upgrade sound quality beyond that of fuses has compelled me to write a review. I’m not associated with Verafi Audio, the company that sells them, nor did I receive anything from them as "review units". There’s another thread on Audiogon about them that an audiophile friend referred me to, which got me interested enough to buy them. I am now enamored with the sound of my system in its current state, so I wanted to share my take on one of the more significant steps in how I arrived here.
Before getting into details about its form and function, I want to share my impression of what the Swiss Digital Fuse Box (SDFB) does for sound quality. It makes my components sound like they are operating without any limitation of power. It sounds open and unrestricted across the audio frequency spectrum. The sound is dynamic, detailed, defined, and there a sense of harmony and completeness about it. It’s like my components can now output their full frequency and harmonic potential.
A few things about me... I’m more of an artist than anything. I’ve been a music lover for 35 years and an electric bass player for 15 of those years playing in two bands, with which I was the bass player on one full LP recording and one EP. I’ve recorded, mixed and mastered my own multi-layered solo bass recordings and their backing tracks from sampled percussion using digital audio workstation software. I’ve also fine-tuned two of my custom car audio systems using DSP software and built, tweaked, and tuned a high end home stereo system (yes I said *tuned*, without using DSP) . Given this experience and the resultant development of a keenly perceptive and informed "ear", yet having no formal electrical theory or engineering background, I feel comfortable suggesting that the results of using SDFB can be likened to how audio sounds when the device producing it is operating with ample headroom. What does headroom sound like? The term headroom has different meanings in its use within pro audio recording/engineering and electrical circuitry operation, but they are related in a way that the end result sounds uncompressed, undistorted, fully dynamic, and expresses the sense of the effortlessness of unrestricted flow.
Does this sound like embellishment? It probably does. And I haven’t even mentioned the typical audiophile terms like "inner detail", "layering", or "rock solid imaging", nor have I even mentioned soundstaging attributes yet -- even though all of these qualities have also gone through upgrades due to the SDFB’s being installed. Am I merely in an irrational, excited state because my whole system now sounds much more expensive than it is? I don’t think so. I’ve been using all four SDFB units for three weeks consistently, and the initial excitement phase I was experiencing settled at least a week ago. I also think that the more components a system has which have replaceable fuses, the greater the potential upgrade from replacing each of those fuses with SDFBs. Like I said, I replaced all fuses in four of my audio components (six fuses in total), and there were notable step-up improvements in sonics as I progressively installed each of them.
Now I’ll describe the physicality of the device and how to use it. Then, I’ll try to describe specifics about why my previous fuse setup, which was a combination of Synergistic Research Purple and Master fuses, was completely replaced by SDFBs. These SR fuses were already a major upgrade in sound relative to the stock, generic fuses, and the SDFBs transcended the SR fuses in every discernible way.
These things have two separate parts that work together: 1) a small box that is inserted as the middle of a chain created between an audio component and the electrical outlet from which it draws power, and 2) a solid, cylindrical metal slug (referred to as a "Sluggo") which is the same size as the typical fuse. To install a SDFB, first, with your component off, plug its power cable into the AC socket on one end of the box, and on the other end of the box there is a male IEC connector (C14) which you connect to an outlet using another power cable or an adapter. I’m using a combination of two short, homemade mini-cables, and two generic adapters with my four SDFBs for the best sound (details shared in my Audiogon virtual system). Once the box is connected to a live electrical line, it will go through a brief setup period, and after maybe 8-10 seconds, you’ll hear a clicking sound and the small green LED will stay lit, indicating that charge is now allowed to flow through the box. The second and final step, with the component still off, is to replace the fuse(s) with a Sluggo. The device comes with both copper and brass Sluggos. You can then turn the component on. Don’t replace a fuse with a Sluggo without the SDFB in place because you’ll have no overcurrent protection and you’ll incur the risk of severely damaging your component and/or having a catastrophic fire in the even of a short circuit or other overcurrent scenario.
These units monitor current magnetically, and are calibrated to whatever fuse rating is needed when you order them. They are also calibrated to operate as either slow blow, or fast blow, like a normal fuse. When the set parameters are exceeded (too much current), a relay is switched to the closed position and charge is halted from flowing. Being non-sacrificial, you don’t need to buy a new one, you just unplug it from the outlet for about 30 seconds and it will reset the state. Then it can be plugged back in and reused. There’s no damage done to the device due to the overcurrent condition, unlike a fuse which melts due to high heat. Currently, devices being produced are to be calibrated at 10 amps max, so if there is some crazy high current event, perhaps then it could be damaged. I don’t know. I believe that’s pretty unlikely though. I think I remember reading that there’s a 15 amp version in the works.
There is some inconvenience involved with transitioning to SDFB due to the extra weight of the box (not that heavy, really) and extra length added to the power chain, as well as potentially requiring additional investment in more power cables. I feel that I achieved an optimal result for only about $200 of additional investment by using some DYI cable materials I had available, some high quality plugs to terminate the cable with, and some cheapo adapters from Amazon. For me, dealing with the extra weight and length to the cabling and putting in the work to create the best solution for connecting the SDFBs to my power conditioners has not been a big deal compared to the profound jump in sound quality. Totally worth it.
Before I went all SDFBs, the best configuration I found with SR fuses in my system was one small Master fuse in the LPS that powers the modem and router (I have an all-digital streaming system), two small Master fuses in the DAC, one small Purple fuse in the preamplifier, and two large Purple fuses in the amplifier. It’s worth mentioning that total retail cost of this setup is about 33% more expensive than the retail cost of my final SDFB setup. However, if you choose to buy a bunch of new, expensive power cables to connect your SDFBs, that would quickly become more the more expensive option.
I thought the SR setup sounded great at the time. I was impressed with the top end detail that a few of the Master fuses added to the fuller midrange and mid-bass sound of the Purple fuses which I already had. I’ve seen comments from others on this site in agreement about this. This combination is getting some praise. However, when comparing that sound to the SDFB sound, it was like the SR fuses are stuck at a level of trying to boost certain frequency ranges to make up for how restrictive a fuse really essentially sounds.
How do you improve on a small, low resolution, blurry, drab looking photo? Well, you manipulate it in Photoshop, of course! You try to crank up values of various visual (light-based) metrics to make it more attractive. However, that process will never produce something as close to the original subject as when you start with an ultra-high resolution, high-dynamic range photograph. You can’t "add resolution" to something that is intrinsically underpinned to a state of reduced resolution. To me, this is analogous to the task of starting with the tiny, resistive piece of wire in a fuse and trying to add crystals and various substances of specific resonant frequencies inside and around it to end up with something representative of the innate completeness of the source material.
Comparatively speaking, I was surprised to switch back to the SR setup and find that the soundstage was compressed towards the center. It was like there was a somewhat spherical haziness in center stage from which the sound was straining to emanate from, even with the Master fuses in play. I attribute this sense of "haziness" to a combination of reduced dynamic range, and a distortion of the frequency response coming from the system’s components. If the hypothetical ideal response for a natural sound (assuming the important aspects of room acoustics and one’s hearing quality are held constant) is essentially a linear response from top to bottom in both amplitude and purity, then the sound of the SR setup was now perceived as distorted and a deviation from linearity.
The sound of the SDFB setup is far more natural, far more detailed, and imparts a sense of ease while listening. I’m using all copper Sluggos, as their tonality is more natural to me than the brass versions. The soundstage has opened up with more dimensionality and all of that perceived haziness and limitation of full expression is (seemingly) completely gone. Images became more defined and image positioning is on a more advanced level. I can now perceive the two singers positioned near center and side-by-side in the mix, with a gap of about about a head’s-width between their mouths. This wasn’t perceivable with the SR fuses. The positioning of cymbals on a well recorded drumset are precisely locateable in space. Listening to Russion choral music, I can now hear individual tenor and bass voices and their unique tonal qualities. On one excellent recording of a solo harp, there’s beautiful overtones resonating that I’ve never been able to hear before. The sound is descriptively harmonious.
Over the course of a couple weeks, the sound of these units opened up. To begin, there was some minor coloration of the sound, but I’m not sure I can hear it any more. I think most of it has gone away as the units have burned in. Even with the minor coloration in the beginning, the immediate leap above the SR fuses in sound quality was obvious and highly desirable.
One last thing, I did a rough test of the overcurrent protection functionality, as this is obviously a major thing to get right and have working properly. I’ve been told that most refrigerators pull about 1 amp of current, so I used that as a basis for testing since I don’t have any more sophisticated method (I could use my desktop computer PSU which has a wattage display to achieve more accurate testing, but I’d rather not have its power suddenly cut and risk problems). I have two SDFBs calibrated to trip at levels below 1 amp, and two units calibrated at significantly above 1 amp. With each of the two sub-1A units inline with the fridge’s power cable (doing two test rounds for each unit), they immediately tripped and the fridge’s power was disconnected when I plugged in the power chain into the outlet. For the above-1A units (also did two test rounds each), the units did not cut power, and the fridge turned on and operated normally. I feel like this testing demonstrates enough for me to have a boost in confidence in the overcurrent protection operational integrity.
Being able to safely use solid metal slugs in place of fuses is wholly a paradigm shift in a high end audio system’s sound quality potential. These things deserve attention and I’m grateful to have been pointed to them.
https://verafiaudiollc.com
Calm down rabble rousers, my bad, my reference is from the song "A Day In The Life" Sgt Pepper. I could make it out before but with the silver slugs in place the words are more clearly defined. I was just trying to explain the added clarity. Sheesh... Evidently you guys don’t remember the Paul is dead controversy. Could be memory loss? ozzy |
@verafiaudio Can you use the Swiss Fuse Box with PS Audio BHK 300 Monoblocks? Those amps have 6 fuses per side with only one power inlet. There are 4 glass 10 A 250 V fast blow fuses and 2 ceramic 10 A 250 V slow blow fuses. It is a hybrid tube input and solid state output design. I have no idea why there are so many fuses or if it would be possible to replace some or all of them with sluggos and your Fuse Box?
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@thyname Lots of people suffer from hearing loss and don't know it. It is kind of like all those people who claim their cartridges with 2000 hours of play time on them are perfectly fine. The change is slow and progressive and easy to go unnoticed. But if @ozzy didn't just make a simple mistake and does have trouble clearly hearing those lyrics it might be time for him to stop posting about how things sound. |
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@ozzy I have to agree with the @thecarpathian . The lyrics are clearly "I've loved them all" and I had absolutely no trouble hearing them even on my modest desktop system (KEF LS50's and a $99 SMS; DA-6). If the lyrics aren't legible you should reevaluate everything in your system or consider getting a hearing test. Fuses are the least of your problems LOL. |
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Update: The first thing I noticed after inserting the silver rods (slugs) was that my tube bias changed big time and needed to be reset. Interesting. I would say that after just a few hours of actual running time what I am hearing is definitely a louder and more dynamic sound. The bass goes much deeper, and the treble is more exposed. Words and imaging have improved greatly. Within the song, In My Life by the Beatles we always thought the words were "eye of Paul", now it is very clear it is Albert Hall. Perhaps at this point the sound is a little too sharp. After all it is pure .9999 solid silver, but I will give it more playing time before passing final judgement. Today I applied some of Ric Shultz Pro on the slugs ends. ozzy |
So, I just purchased some .9999 7-gauge solid silver rods. I may need to solder 2 of them together, but my intention is to use it in place of the copper slug. UPDATE: I just received the silver rods. First off what a PITA trying to solder these (2) 7-gauge rods together. I used silver solder no less. Then it became over diameter and would not insert into the tube holder, so I had to grind them until they did fit. I just installed them, and I will update my impression after some more hours. ozzy |
Any SR and the Acme fuses were tremendously superior to a Bussman and Littlefuse glass or ceramic fuses in my EAR 864. I was not using it for a decade and was about to sell it because it was very forward sounding and lacking in any depth. All of the aftermarket boutique fuses were excellent to spectacular. The preamp now has depth, open sound, dynamics, etc. to the extent that it totally trounced an EAR 912 auditioned in my home last week. Both units had NOS tubes and the 912 has an SR purple fuse. That’s how important these aftermarket fuses can be. P.S. The apparent reason for the 864 sounding so great is the Mullard 4004 & RCA cleartop 12AU7, very musical sounding tubes versus the 912's Amperex/Philips 6992/6DJ8 non-audiophile designed tubes. The latter preamp had amazingly open sound but sounded smeared and bloated compared to the 864 which presents a smaller but very precise image. |
@carlsbad2 I am responding to an earlier post of yours. I totally disagree based on my own equipment. The biggest change is in my DAC and Pre-amp between fuse manufacturers and type. Acme special-total failure/worse than the standard fuse in the DAC (weird, same fuse used in Pre-amp now/same rating). The SR purple fuse in the DAC is a HUGE improvement. The EAR 890 amp sounded fine with a standard fuse, more open and detailed with the SR purple and added better pace and resolution with the coated Cryoed Acme. Also, that Acme fuse doesn't blow at the same rating as the SR fuses which really need to be higher rated for slow blows. My friend and I have the same DAC so we know how important the right fuse is. As to the amps, we also own the same 125w/ Class A/B tube power monoblock amps (other than the EAR 890). When he heard what my SR blue fuse did to the amps, he did one better and installed a pair of 5 amp circuit breakers in his pair. Sounds slightly better and he has no fear of it blowing up (tripped once in a decade when a tube blew). However, my SR blue are 8 amps (lower blows despite the 5 amp rating). Circuit breakers are a better choice when possible. |
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@thyname : I joined Agon in 2016. No need to tell you that user name. I had 4000+ posts then! Then I got a new phone and couldn't get back on here with that first user name. So I became jasonbourne52. Then that phone died when I had 2863 posts. Now I am on my third phone and third incarnation! |
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Claiming to hear a difference between a plain slug and a polished slug is just nuts! Back in the days of yore there was a discussion in the letters section of TAS about the sonic merits of polishing the chrome blades on AC plugs. The more things change the more they are still the same - translated from the French! |
Hmmmmm…. Your profile says you just joined earlier this month: https://forum.audiogon.com/users/jasonbourne71
What am I missing? 2016? Maybe under other usernames?
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Whether @recklesskelly is those other banned usernames or not I still think he has some valid points here regarding certification. I think that the device is intriguing and maybe it does exactly what you say it does. I’m still weary of using a device that hasn’t been certified. Good luck to you though. It’s definitely an innovative product |
@thecarpathian no I am not and quite frankly I am tired of the accusations. Tammy is aware of you and your little gang. |
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None of this undergrad academic credential jockeying has anything to do with the actual sonics of replacing fuses with slugs by using SDFB. Purely based on the same stubborn pattern repeating without end, it appears Jason was Bourne to be an internet troll feeling desperate to be perceived as the superior intellect, regardless of experience. Basic business reality and profit margin doesn't seem to click either. |
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@jasonbourne71 looks like you went ot Uconn with my brother. He got a PhD in English literature, not much more useful than your 2 years w/o a degree. But he is a professor now, teaching other people about 600 to 800 year old plays. I have some experience with SCRs in superconducting magnet power supplies. They weren't terribly reliable but I have one cut in half for forensics around here somewhere. An SCR crowbar is an overvoltage protection circuit. we are looking for overcurrent protection. Good try....no, not really. Using a breaker to replace a fuse is not patentable. I could develop my own flavor and go compete. (not a threat, I'm too busy with my day job and modding my system). It is pretty easy to understand how this works: jumper the fuse and insert a magneticly tripped circuit breaker. They say they adjust it to trip at your desired current although it would surprise me if a small breaker like this is adjustable so I'm guessing they use a bridge circuit or something similar. The setting isn't that critical. Most manufacturers wet their finger and hold it up in the air to pick the size fuse they use. and here's a dirty little secret, one reason the expensive audiophile fuses sound better is because they pass more current and fail at a higher value. Note this is different than your home protection breakers which are sized for the wire in the circuit and should never be changed without an engineer's help. this type of sizing isn't possible for an exlectronic component. Stick to drafting. Jerry
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@thyname : No, I was a math major in college. Though I have always been interested in Mechanical Engineering and Material Science. Plus I am an excellent draftsman! |
@jasonbourne71 sorry I will delete my post. You can take care of this. Go in peace. |
@thyname : That's the fault of the Agon programming! It only allows one email per name. When I tried to use my other emails I always got stuck in a loop - "user name taken" and "email incorrect"! Back and forth! So now I sign in using Facebook. |
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May I ask, why do you change the usernames?
By the way, I love the choice of your “friends” in your Facebook! Juicy 🤦♂️
https://www.facebook.com/robert.jermantowicz/friends
Oooooohhhhh. Enigmatic 🤯😱
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@carlsbad2 : Look up "scr crowbar circuit" on Google. I'm surprised you don't know about it! It does work instantaneously! I am curious what exactly is inside that $395 box? Micro processor Hall effect - yeah? If I had a peek I could copy it and go into business! Apparently the circuit is not patentable! |
@jasonbourne71 I usually ignore you since you are farther toward "nothing matters" than those you criticize are toward "confirmation bias". as with most things in life, the answer is in the middle and you’ll never find it locked into one side or the other. Since you addressed me by name I’ll reply. You ignore how much a fuse degrades the sound. As I’ve posted earlier in most cases I evaluate the risk and replace the fuse with a slug achieving even more than the SDFB does. I have worked 40+ years at a power plant where I’ve been responsible for thousands of very high end breakers as engineering manager. I’ve been looking for and even challenging my electrical engineers to find a magnetic breaker that I could apply like this. I was going to make mine slip into the fuse box...as you can see there is an emotional resistance to putting a slug in a fuse holder, even if there is a breaker 2" away. But this guy beat me to it. and while I did criticize the price, and I would never have picked such an oozing-with-marketing sounding name, this is not expensive for high end audio equipment. I’d say his markup is less than the high end calbes you don’t believe in. I’ve never heard the SDFB in service but if the magnetic breaker he has found provides a high current, resistance free circuit (unlike fuses or thermal operated breakers which use a high resistance bimetal strip in the circuit) then I think this will provide about as much bang for the buck as any upgrade you can do (short of my slug-without-breaker mod). Jerry |
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@thyname his other moniker @jasonbourne52 is still active, no conspiracy here. Could have a new device and forgot his password. You can look up servers and find out if they have been banished. |
@jasonbourne71 : let’s try this again
I am curious, what happened to your previous Jason Bourne moniker? You had 3,000 posts with it, all in the same vein https://forum.audiogon.com/users/jasonbourne52
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