I got word from Rob Woodland of Eichmann Technologies of Australia that the RCA
phono plug had been reinvented by Keith Eichmann and was going into production,
I was very curious of course. What would the new plug be like and would it function
better than any other high end phono plug?
When I saw the cutaway of the Bullet Plug - as Keith's invention is called - my
curiosity was even greater, but at the same time I saw already one aspect of which
I knew that it was beneficial: just the bare essentials and nothing more.
the least signal loss - especially in analog connections (phono, pre-pre) - I
always prefer and use the cheap, plastic RCA phono plugs which have as little
metal as possible, instead of the bulky, high-end, luxurious types which suggest
the bigger-is-better quality and are attached to many so called high end cables,
or have been soldered by hobbyists to their own chosen leads. But as I have found
out: Golden shine can blind your eyes but should not fool your ears. It all depends
on what is underneath the polished surface.
The very tiny and rather weak signals generated by a phono cartridge should not
meander through much metal and loose their integrity. Especially the signals of
MC cartridges need great attention. My idea always has been that after the phono
signal had been amplified significantly, the more sturdy type of plug could be
I was pleased to see that the connection of the earth lead, which is a collar
normally, had been replaced by just a pin. There is however another significant
construction detail of this earth pin. To the eye it is tiny, but one is easily
fooled. Indeed it is small in diameter. However Keith Eichmann found that there
should be a specific ratio between the earth and the hot signal in loudspeaker
cables and interconnects. He
calls it rightfully the "Eichmann Ratio" and does apply this also to the Bullet
Plug. The formula is a ratio between the signal and return conductors, where the
return (small pin) has greater cross sectional area and mass than the signal (large
pin) – based on the wall thickness of the signal pin. This, notwithstanding the
fact that the cutaway of the Bullet Plug may suggest otherwise.
are more reasons of equal importance why the Bullet plug was designed this way.
The classic phono plug lets the signal suffer from “Eddy current” distortion as
electrons proceed to and from the RCA socket into the collar through multiple
contact points. There also occurs a "Capacitive” distortion where gaps exist between
the socket and the collar, the air being the dielectric. And finally there is
“Micro-arcing” distortion which is brought about by an electrical short that can
occur where gaps exist between the socket and collar. Although these are new to
most audiophiles and technicians as well, it explains why already in the nineteen
seventies many hobbyists soldered the cables of the sources (especially those
of the signal from the turntable) to the amplifier's inputs and also from the
outputs straight to the loudspeakers in order to achieve a pure as possible contact.
They could not explain the technicalities, but certainly had heard the difference.
Except for the
true high end brands (like Cardas for instance), most connectors on the market
are made of brass. And brass has a very low conductivity. It will transmit only
28% of the signal. It is clear that in order to have a maximum transmission the
use of brass should be avoided. The metal which provides undamaged signal transmission,
or in more scientific terms: will not inhibit the flow of electrons, is US Tellurium
Copper. And why not use copper if the cables you use are highly conductive because
they probably are made of copper as well (if you do not use silver conductors).
To counteract corrosion the pins are gold plated.
If you have looked carefully
at the image, you will have noticed that the earth will not connect with its full
length, but just with a small surface over a few square millimeters. This way
the flow of electrons is concentrated at that specific point and cannot dissipate
and loose its integrity.
is another novelty. When I asked Robert Woodland about the use of nickel in relation
to the gold plating of the pins he answered: "We were able to apply gold
plate directly with none of the problems associated with direct gold plating standard
copper. You will notice that the gold plate on the Bullet Plug contact pins is
quite dull. With a nickel substrate the appearance is very shiny. The gold plate
is 20 micro-inches thick, or 0.00005mm. It is purely there to prevent oxidation
- not to contribute in the conductive process. In fact gold is less conductive
than tellurium copper."
these details about the design is theory of course, but practical theory as you
will find out, and certainly not a formula for the sake of having a formula for
marketing purposes. The Bullet Plug works.
As you may know by having visited "Audio & Music Bulletin" (see the link at
the top)I am a lover of analog recorded sound. After receiving a pack with 4 Bullet
Plugs I cut off the old plugs of the phono cable I had been using and soldered
the Bullet Plugs on that same cable. Changing cables would certainly lead to less
objective evaluation. After a few hours already, but certainly after a day or
two, the plugs and the very little solder I used, were practically burned in,
although I discovered that the signal continued to improve the first days.
dissipation of the signal in many conventional plugs leads to anomalies in time.
That means that the phase of the signal deteriorates and the harmonics of acoustic
instruments are being hampered because not all information does reach the amplifier
at the same instance so to speak. Now the complete signal seems to be intact,
has speed and sounds tight, which means that the phase is correct.
A weakness of my
active speaker system, which I attributed to an incorrect adjustment, was entirely
gone. There is no make belief openness and space which are often displayed by
bulky plugs. Now the orchestra sounds straight. Transient response is exemplary,
also because the midband is in phase now. The sound has become more dynamic and
articulate, which is specifically apparent in the brass section in symphonies.
Playing Rachmaninoff's 3rd Symphony for example, conducted by Walter Weller on
an original DECCA, the timpani has a firm attack and the brass players stand out
with warmth and clear sonority.
strings have more texture. Cymbals have that build up and presence which one hears
in the concert hall. Henryk Szeryng playing "Kreisler Favorites" (a beautiful
Mercury recording on a even beautiful Fontana pressing by Philips) displays a
violin tone with uncanny realism and sharpness. The variations in pressure of
the bow on the strings have significantly improved.
Phase is a very important aspect. If the phase is not correct, people with sensitive
ears can easily feel a sort of nausea. Now
there is complete acceptance of the displayed sound by every and each listener.
signal transmission has its effect on every recorded instrument in all sorts of
music. The grand piano of Ingrid Haebler is more real and has more felt on the
hammers. The bass of Ray Brown on a Contemporary record playing with Barney Kessel
and Shelly Manne is more snug. Voices in choirs are broad and articulate. The
quality of pressings and the way the recordings are made is more evident than
The significant improvement came about by just starting at the turntable side.
you consider to go for the Bullet Plug, I would suggest that you start with a
4 pack and treat the front end signal of CD-player or phono cartridge. That
is: if you have become interested enough.
If after this trial you are as satisfied as I am, you can procure more Bullet
Plugs and continue to improve more signal paths in your hi-fi system. After connecting
my MC phono lead with Bullet Plugs I have continued improving the connections
between my active crossover and the two main amplifiers. For these connections
I originally did use Isoda Hybrid Cable which I had chosen several years ago because
of its cleanness, but which I have changed for another type.
Bullet Plug accepts the Isoda cable easily. At one end I always solder the shielding
together with the earth wire (black) to the Bullet Plug. At that end I connect
the cable to the source, in this case the crossover. In this way the shielding
of the housing of the crossover is extended all the way to the power amp. Making
the connections with the Bullet Plug meant not only a further improvement of detail
and strength, but contributed significantly to a deeper and wider stage, for example
when listening to Les Brown and His Band of Renown. It must be that through the
Bullet Plugs the transmission of the low and high section signals gained in equality.
This of course can be attributed to the precise physical properties of the connectors.
is generally very easily done. And in case you are not satisfied with the cable
you initially used with the Bullet Plug, do not worry, the Bullet Plug is easily
removed and reused of course. The plug's body is made of a very hard quality plastic
which does not deform or melt easily (like the plastic of the ordinary type of
plug). The design is such that it procures a snug fit on all apparatus. That is
why it is advised to gently heat the red/black flange with a hairdryer before
fitting the plug to large RCA sockets.
is the time that you will hear the quality and characteristics of specific cables
more than ever. Now a cable choice is more significant. The Bullet Plug accepts
cables with a maximum diameter of 9 mm. And to finish of the construction of your
own interconnects, you may want to use a (clear) heat shrink wrap over the outer
housing where the cable enters the housing. This may provide a more secure, long
Bullet Plug lets you also hear the design of circuits and the sound characteristics
of amplifiers instead of blurring the information. Except for the interconnects
of my Tandberg 10X tape recorder and Denon DCD 2560 CD-player all leads have been
fitted with Bullet Plugs. And I am very happy with the improvement in precision,
detail and cleanliness of the sound. 'Recommended' is my verdict. The improvement
made me think and wonder what the next step would be. That is: what about female
plugs and the RCA sockets on the chassis of the various components? Robert Woodland
told me that a concept is on the drawing table. So, in due time we will have another
image below shows the generally adopted way to make the connections inside the
Bullet Plug or any RCA phono plug. The preamplifier is the central point in the
chain. There the shielding (earth) has to be connected to the negative conductor.
At the end of the power amplifier the shield is not connected. The idea is that
the chassis of the preamplifier extends to the chassis of the power amplifier
through the shielding of the interconnecting cable. So in case of phono cartridges,
pre-preamplifiers and step-up transformers, CD-players, etc. the plug at the preamplifier
has the shielding connected to the negative. This method can only be used if you
have a cable with two conductors (leads) plus a shielding.