I got word from Rob Woodland of Eichmann Technologies of Australia
that the RCA phono plug had been reinvented by Keith Louis 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 used.
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is a collar normally, had been replaced by just a pin.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 he appli8es 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 me and 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 loudspeaker cables in order to achieve a pure as possible contact.
They could not explain the technicalities, but certainly had heard
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
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 a 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.
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.
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
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
The improved 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
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 term fitting.
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 surprise.
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.