FUSE BOX delivers perfect protection and superior sound

Encouraged by the improvement offered by the PURON plug-in filters, I spent some additional time reading 


I wondered if a second product, unrelated to PURON, can also raise the bar for recorded music?  FUSE BOX is a system that replaces a fuse in a piece of electronics.  A metal SLUGGO (insert either the brass or copper option) goes in the fuse holder.  The power cord you have been using goes into one end of the slim, lightweight BOX.  From the other end of the BOX, another power cord (quality counts!) leads to your power conditioner or to the wall.  Simply plug and play.

Each FUSE BOX is calibrated according to the traditional fuse it will be replacing.  By providing the amp value, fuse size, and slow/fast blow, a unit can be tailored to your specs.

I took the plunge by requesting a FUSE BOX to fit into two different systems.  I use a Black Ice FOZ SS-X Sound Expander in both a headphone (Synergistic blue) and main system (Synergistic orange).  This wonderful piece is in the middle of both systems, between the cd player and the amplifier.

Starting first in the smaller system, there was a break-in period of about 30 hours before the sound really took off.  A huge positive step (for me) was then replacing the copper sluggo with the brass version.  Now I heard the depth and warmth, in addition to the detail of the copper version.  The traditional Grado sound through the over the ear headphones (Prestige 125 model) was rich, detailed, and balanced.

I spend much more time listening through full range Martin Logan Expression ESL 13a speakers.  I recently added two PURONS to this system, plugged into a Synergistic Research Powercell 12 conditioner.  Even when (intellectually) I believed this combination had already taken me to the "top of the mountain," I was happy to be proven wrong.  With the brass sluggo in the SS-X, the "you are at the recording event" is very powerful, and in a way I had never heard before.  It's like I have the best seat in the house, for every recording.

For me, FUSE BOX offers the protection of traditional fuses, without fearing they may need to be replaced (since FUSE BOX can be easily reset).  With the two sluggos provided, the sound can be adjusted to one's preference.  And I still have the flexibility to change this arrangement in the future, as the sluggo is never permanently fixed to the fuse holder.

A big thanks to Mark Schifter at Vera-Fi Audio, for patiently helping me.  With a 30 day return policy, my guess is that many music lovers will be asking Mark to program a unit, so they can evaluate it in their systems.

My answer, to "how can the sound possibly get any better?" is FUSE BOX.  Highly recommended.



In my system, I prefer the copper sluggo as it’s closer to scale in terms of image size; if you thought your speakers were holographic, wait until you add a Fuse Box and your front wall becomes a "chameleon".

Will do more listening between the sluggos after more settling in time...


Thanks to the earlier adopters of this product for posting.

If anyone has a link to comprehensive product information, I’d love to have it. 

It sounds like the product comes with sluggo’s of brass and copper for the user to experiment with.  Is that correct?  

Wig, rareace….did you replace the stock powercord on the fusebox or are your positive reports based on the stock cord?


Yes, the Fuse Box does come with a copper and brass sluggo's. 

The Fuse Box is not shipped with any power cords and using PC's I currently have on hand.



Sorry for not posting for a while, I have had many personal items of late that took me away from listening to music.

I have had the fuse box(s) connected to my amps for about a week, probably have played music with them in the system for a total of 10 hours.

What I can offer is that there is no downside, I am hearing a calmness that is pleasant, perhaps my amps are finally playing as to the way they were designed.

I have only tried the copper slug thus far, but I will try the brass.

BTW, I did make a short 12" jumper power cord to use with my units. I think Mark will soon be offering a similar power cord to be used instead of connecting another long power cord to the Fuse Box.



Mark was kind enough to send me 2 of the fuse boxes to try on my preamp and power amp.  I'll do my best to give my impressions, though I feel like the sound is still changing and improving.

Out of the box (copper sluggo):

Bass.  More in both quantity and definition.  I considered dialing my subwoofers back a few times in the first hours, but eventually decided it sounded 'right' with my original setting. 

I'm noticeably lower on my line stage's volume control.  Maybe 5 steps lower (out of 103 total).  I usually listen around 30 and am now listening in the mid 20s.

Instrument separation is better and the leading edges of notes are more clearly defined.

Soundstage depth is reduced slightly.  Soundstage width is unchanged but the outer edges of the stage are more illuminated. 

Complicated passages are congested.

Vocals and high frequencies sound a little etched and somewhat artificial like I'm trading some naturalness for additional detail.  

After a week (approx 25 hours):

Soundstage depth is back to where it was.  Improvements in width and illumination remain.

Congestion on complicated passages is no longer an issue.

The etched quality I noticed initially has settled down nicely and things are sounding natural again.

I like what I'm hearing.


I have lent the fuse boxes to a friend of mine for a couple of days to try on some other equipment.

Before I removed them from my system, I briefly tried the brass sluggo.  I think it is the better sounding choice for my system.  Tonality and texture on stringed instruments seems appreciably better.  High frequencies seem more natural and appropriately scaled.  I'm less confident in these observations because they were made in about a half hour but will follow up when I have had more time to compare.

Last night, I listened without the fuse boxes in my system.  It was a short session, not as engaging.  I'm looking forward to continued experimentation with the brass sluggos.

I'd also like to try polishing the sluggos and treating them with progold or bullfrog contact enhancer.