Component Reviews

Three Audio Tweaks = AudioPrism Ground Control FIM Formula Eight Disc Enhancement Mat Cardas RCA & XLR Protective Caps

Three Tweaks laughed at by some, but praised heartily by others.

Published on July 9, 2010

Three Audio Tweaks = 
AudioPrism Ground Control
FIM Formula Eight Disc Enhancement Mat  
Cardas RCA & XLR Protective Caps

Three Audio Tweaks =

AudioPrism Ground Control  SRP: $149.95; Reference Version $249.95

FIM Formula Eight Disc Enhancement Mat  SRP: $129.99

Cardas RCA & XLR Protective Caps  (SRP: RCAs $3.69 ea., pair of XLRs  $29)



Box 24203
Seattle, WA 98124

First Impression Music

Cardas Audio
480 11th St. SE
Bandon, OR 97411


It’s a difficult task to review audiophile tweaks. Anything that falls in the “unexplained” area is definitely going to get a rise out of the objectivists and Skeptics Society members. There are many variables in a particular audio system, as well as variables in the physiological process of hearing.  A tweak that might do absolutely nothing for one system or for one listener might make worlds of enhancement in another system or with another listener. Some tweaks can make an immediately-hearable improvement in entry-level gear while hardly being noticeable in true high-end systems. While others seem so subtle that only with ultimate audio components can their contributions be recognized. Some systems have such serious overall problems that the enhancement of even the most successful tweak simply cannot be heard.

Ground Control

AudioPrism has specialized in various audio tweaks for many years now. Their past products such as CD Stoplight (the green paint on the edge of CDs), QuietLine and ISO-Bearings are familiar to many audiophiles.  Now they have a new item that is stirring up the audiophile community something fierce.  Called Ground Control devices, they are little white cloth-covered pieces of wire that attach via spade or banana plug to the negative-only terminals of loudspeakers.  Like many audio tweaks, they don’t look anything like gadgets that would cost $150 a pair. There is also a spade Reference Version, which I didn’t try.

What they do is described by AudioPrism themselves as “a self-contained local ground storage mechanism for all of the electrostatic moments that occur in music being reproduced bia a given circuit or component. They help maintain the coherence of electrons involved in signal transer – i.e., making music – thru CD players, preamps, amps, and of all surprising things, speakers.”  Their literature points out that in the early days of audio, radio amplifier circuits had a solid copper plate – a ground plane – and the wiring was point-to-point, with attention paid to consistent spacing from this copper sheet.  It provided shielding from external electrical fields, and established a local reference point for a ‘zero signal’, and provided storage for electrons representing the negative half of all signal activity.

Today, however, those copper plates of old are no longer in our electronics, but instead are located under the streets or at the local AC power station. There is no local support of the negative half of all the audio signals, and that is what Ground Control provides. They may just look like a short piece of cloth-covered wire that couldn’t affect anything, but they have complex windings of 138 feet of very fine wire inside. They come in versions for speakers with either spade lugs or bananas plugs, the spades being regarded as superior. There is also another version with RCA plugs for amplifier and receiver use, but its effect is not usually as noticeable and I stuck to testing only the speaker devices. Those of us with bi-wired or bi-amped speakers would need a pair of Ground Controls at each speaker, attached to the two negative terminals.

Ground Control Listening

AudioPrism advises turning everything off before attaching or detaching the Ground Controls, but I found the long delays and warming up of my tube amps interfered with my A/B comparisons.  Most amps wouldn’t be bothered by temporarily detaching the speaker connections to hook up or unhook the Ground Controls (you should mute the volume), and in fact the best method of all is to have someone physically attach and detach the Ground Controls while you listen to test material at your sweet spot. I do most of my listening with my multichannel system in operation, even if the original source is only two-channel – unless it fuzzes up the front channel sound.  So I obtained enough Ground Controls to hook them up to my two surround speakers as well as my front center channel speaker. I had replaced the chrome jumpers on the surround speakers – which are not bi-wired – with heavy copper jumper wires. (That was the most amazing tweak I ever made on my system and I highly recommend it!) Therefore I couldn’t fit in the spade connection Ground Controls and was forced to use the banana plug versions on those two speakers.

AudioPrism advises a break-in period of about an hour, although there should be an identifiable enhancement right after switching. The effect does gather steam as time goes on.  I started with the F.I.M. demo disc “This is K2 HD Sound!”  Track 1 is the beginning of Rachmaninoff’s Symphonic Dances, with Eiji Oue and the Minnesota Orchestra, from Reference Records. This is a great demo excerpt, with rich sonics and an amazing dynamic range. With Ground Control the music has increased impact, more extended frequency range at both ends, more clarity, more depth and deeper bass support. While the enhancements were subtle, they were definitely there. Track 2 of the K2 disc features flamenco guitarist Pepe Romero with two zapateado dancers. Ground Control provided more ambiance on the sounds of the foot-stompings, and one of the dancers moving from right to left and then back was more distinct. The third track is a soloist on the Chinese erhu, with a jazz trio.  The doublebass had more extension and impact, and the wiry sound of the erhu was stronger, with more presence.I next switched to a Sony stereo SACD disc, George Szell and the Cleveland Orchestra in two movements from Mahler’s unfinished Symphony No. 10. The Ground Control-equipped playback showed more depth on the opening strings on the right channel, and the other strings that later came in on the left channel had more impact when they did. The extreme high end string tones were more extended and richer.  The highest string tones were a bit strident and steely-sounding; this is not a state-of-the-art SACD transfer.  However, the Ground Control gave the rest of the orchestra more immediacy, which seemed to diminish one’s attention to the highest edgy strings.

I should mention that I have a number of tweaks already on all of the Von Schweikert speakers in my surround system, and perhaps if I had none, the Ground Control enhancements would be even greater. The four main speakers are filled with lead shot and sand, they have lead weights on top of them, felt absorbent surrounds on the tweeters, Kimber Monocle speaker cables, and an early version of the Bybee speaker filters on each one. And the front left and right speakers are bi-wired.

Sometimes tweaks make a difference but not necessarily an improvement. I don’t feel the Ground Controls take away anything or unnaturally emphasize certain parts of the spectrum. I certainly wouldn’t want to take them away. Let the skeptics have a fit.

F.I.M. Formula Eight AV Disc Enhancement Mat Model CF-1


For years now some audio buffs have been putting a second CD on top of the one they want to play in players that can handle that extra thickness. The idea is to spin the pits more evenly and with less vibration due to the extra weight and flywheel action, thus enhancing the payback quality – even though all-digital system are supposedly unaffected by such mechanical things. A few small audio firms have come up with their own thinner, specially-designed mats to place on top of the CD you are playing.  I reviewed one in the past here. 

The new Formula Eight Mat from First Impression Music is thinner and has two sides for supposedly different enhancements to the disc you are playing. It is also less expensive than the Marigo. The thinner 120mm disc was welcome in my situation because I found the Marigo disc would sometimes get hung up with certain CDs and SACDs. I can’t use either disc with DVDs because they are slightly thicker to begin with. At least that’s the case with my Oppo BDP-83SE player – different players have differing amounts of clearance in the tray. Of course the safest use of any of these mats would be with a top-loading CD player.

The Marigo disc has two sides – one for use with CDs and the other for DVDs. The F.I.M. disc also has two sides, but not for different formats. Instead, one side is carbon fiber and designed to enhance definition and dynamics, while the other side is a green color – RCC (Resonance Control Coating) material designed to enhance harmonics and detail. The smooth carbon fibre side (up) is said to improve the soundstaging and is particularly effective with big orchestral works.  The green side (up) is said to also improve the tonal spectrum of the music being played. As with all such discs, it is vitally important to align the mat disc exactly on top of the disc you are playing; otherwise it could get stuck in your player.

The enhancement provided by these discs is extremely subtle, and it varies depending on the particular CD being played, the deck it’s being played on, and one’s entire system. I can imagine that on very inexpensive CD players it might make a major improvement, but then again in the most advanced audio system it might be easier to ascertain the enhancements provided by the mat. Some CDs are quite grossly out of round, and these would be greatly helped by the mat. (One of our writers has the gadget which actually shaves off some of the edge of CDs to make them perfectly balanced.)  Some of the plastic drawers in even some high end decks are far from solid, and the added mass of the mat can provide a real improvement in CD playback on those. (Also adding mass with lead-foil tape can help a bit.)

When there is a substantial enhancement with the mat, I feel it is in the area of greater clarity and transparency, bringing out more details in the music on the disc. I use it on all CDs and SACDs – just not on DVDs with my player. I must admit I hear no serious difference between the green and black sides of the mat, however. I had a friend do a blind listening test for me of discs with and without the mat.  I’m afraid my correct guesses were only slightly better than chance results.

Cardas Signature RCA & XLR Protective Caps

These three tweaks seem to be going in a somewhat downward direction as far as enhancements to my system’s sonics. But the results may be different in your system. The idea behind Cardas’ various protective caps is to cover all the unused jacks on the back of your AV receiver or preamp to eliminate EMI and RF noise pickup, and at the same time to protect the inside of your component from dust and dirt as well as corrosion on the jack.  With the huge number of inputs and outputs on the rear of most receivers and AV preamps today, there are a large number of unused jacks after you hook up all your various components. In my Sunfire preamp, for example, there are ten balanced female XLR jacks going unused, since I use RCA cables.  (Make sure you don’t confuse the male and female forms of the XLR connectors and order the wrong caps, as I did on my first order.)

The Signature caps are made of nickel-plated brass with the well-known Cardas Nautilus logo on top. They look good and do not short out the inputs like traditional shorting plugs, because some preamps and receivers do not like that.

What I’ve found is that the two hot pins on balanced XLRs are positive and negative, so any noise they might pick up or create cancels itself out – this is the big advantage of going to balanced operation if you can afford it and have the proper XLR jacks on your components. It has also been found that for an audio input to pick up any RFI interference, it needs to be attached to a length of wire at least 16 inches long. (I ran into that with a tubed phono preamp picking up a local FM station.) However, there is nothing at all sticking out 16 inches from an unused jack. Thus the XLR caps take on more of a purely decorative function.  The RCA caps could be somewhat more functional and they also look great.

Aside from that pesky rock FM station (which the solid-state Phonomena II phono preamp solved), my system benefits from a very clean sonic environment – no industry or electric equipment-intensive businesses nearby and highest-quality AC power from a very nearby power substation.  I had a separate AC line run for my AV system, a new main panel, and my original Bybee AC conditioner takes care of any subtle noise that might remain on the line.  I also have AudioPrism’s QuietLines thruout my house. Therefore some of the tweaks designed to ameliorate problematic AC lines are just not required.  For these and any audio tweaks, it should be understood that it is a ‘results may vary’ situation, and if you can try them out first – via a friend or the supplier – it may be the best all-around approach.

Before leaving tweakdom, let me mention two other tweaks I highly recommend: raising your speaker cables up off artificial-fabric carpeting. (I use old brown phone-line insulators I found near the creek on my property.) And before playing all discs – optical or vinyl – I give them a good zapping with my MapleShade Iconoclast – a super-powered version of the old Zerostat. That’s yet another ‘Who knows why? But it seems to work’ audio tweak – and is less hassle than the Bedini disc spinner, which it replaced (and couldn’t do vinyl).

John Sunier

on this article to AUDIOPHILE AUDITION!

Email this page to a friend.   View a printer-friendly version of the article.

Copyright © Audiophile Audition   All rights Reserved