yourself to be amazed. The Z-Systems RDP-1 is one of the most
revolutionary high end audio products I have ever encountered. Imagine
this; the lights are dimmed, you spin one of your favorite CDs, but the
sound is less than what you hoped for. What do you do? Change an
interconnect, re-bias a tube, write a letter to a tweaky print magazine?
The answer is none of the above. With a snifter of thirty year-old port
in one hand and your Z-Systems RDP-1 remote in the other, you may now
confidently make your music come to life.
The Z-Systems RDP-1 is a $5000 digital preamp
and tone control that serves as the control center for even the most
high end audio systems. The Z-Systems RDP-1 accepts 6 digital inputs
and then places the digital signal on top of a 40 bit - that's right 40
bit - word. From there, you have the option to add up to 4 bands of
digital EQ, a digital high and or low pass filer, plus digital volume
Z-Systems RDP-1 re-quantities your 16 bit 44.1 digital word into a 40
bit word. With 40 bits of resolution you have the clarity and headroom
to augment your music digitally, in ways never before possible. If you
own a serious high end DAC (i.e. a Levinson, Krell, Apogee, Spectral,
dCS Elgar, Wadia, Theta, etc.) that can accept either 20 or 24 bit
words, you are really in business with a Z-Systems RDP-1. The Z-Systems
RDP-1 can downconvert your 40 bit digital word to either 16, 20 or 24
bit words as to best feed your digital processor. Thus your Z-Systems
RDP-1 is a quick and easy solution to the 24 bit issue in a world where
almost every CD you can buy is 16 bit 44.1 MHz.
Musical Magic with the RDP-1.
The RDP-1 has three knobs and an LCD screen that can be hard to get
used to if your not familiar with the basics of EQing your audio
signal. Do not be alarmed, the Z-Systems RDP-1 is easy to learn how to
use. Simply, you are given as many as 4 parameters to set EQ points for
which you can raise or lower a frequency as well as decide exactly how
narrow or how wide that EQ effects will be in the overall frequency
range of the system.
Here is an example of how to use your RDP-1 to make your music really sing:
1. Put in a CD you love, but know sounds boomy in the mid bass. "Sledgehammer" from Peter Gabriel's So record comes to mind.
Select number 1 of the 4 EQ parameters on the remote. Use the gain
control (it is a +/- adjustment) on the remote to select a frequency of
lets say, 63 Hz to add in this case some deep bass. Bump the deep bass
up to about +2.4 to 3 dB. Keep the slope adjustment narrowed to 1 for
3. Follow the same procedure for
the second of the four presets for a mid bass frequency of 120 Hz. In
this case set the mid bass parameter to -0.6 or -0.8. Once again, keep
the slope to 1 based on how close the two EQ points are.
Rule #1: The
number one rule of EQ is you always use your ears as a guide. Only your
ears know what is right. Don't worry about what anyone else says, you
and only you, know what sounds right.
As you spend more time with an RDP-1 you will find that the best
results are attained by adding EQ as if it were a flavorful spice. A
little goes a long way.
You will find the results of
the above EQ setting to change a `boomy' sounding recording into one
with much tighter and more punchy bass. You may consider reserving one
of your 100 presets in your Z-System's RDP-1's memory bank for this one.
Taking the sizzle out of the bacon.
up the bass is only one of the tricks you can perform when you insert
the Z-Systems RDP-1 into your system. Hot sounding CDs or bright
tweeters can be easily tamed by creating a high frequency EQ point
(perhaps 14 kHz) and ever so slightly reducing the frequency. Depending
on the bandwidth of the brightness you can also adjust the slope of the
parameter from very specific to very wide.
method is to insert a low pass filter to gently EQ the high frequency
information in the signal path while allowing almost all of the rest of
the audio signal to pass untouched.
I use the low pass filer to overcome the ever so slight brightness I
find my Wilson Watt Puppy's to have in my room. It only takes -0.2 dB
of EQ to cool down my Watts in my room. This solution is a heck of a
lot easier getting involved with cable neurosis or replacing
How does the Z-Systems RDP-1 sound?
Unlike other excellent analog tone controls such as the Cello Audio
Palette ($23,500) and the Avalon Design 2055 ($5000), the Z-Systems
RDP-1 is a product that has both a digital tone and volume control. I
found the RDP-1 to have very little audible flavor, but radically
positive effects on the sound of the musical signal.
The RDP-1 is not as warm sounding as the Cello Audio Palette or the
Avalon 2055, yet it is very neutral and perhaps even a bit dry in
comparison. The Z-Systems on the other hand is not another analog
device added to the signal path. My listening test found the RDP-1's
dithering to improve the sound of my system even without any EQ. I
would surmise that my 20 bit Mark Levinson No. 36s 20 bit DAC was more
happy being fed a 20 bit dithered signal than a standard 16 bit signal.
The RDP-1 as a stand alone preamp.
You can use a Z-Systems RDP-1 as a preamp with the addition of a $625,
20 bit analog to digital converter you can take 8 digital and 2 analog
inputs into your RDP-1 and switch and attenuate them digitally. Does
the RDP-1 sound better as a digital preamp or in addition to an analog
preamp? It depends. I have been using a Balanced Audio Technology VK5I
preamp in my reference system. With the BAT out of the loop you
obviously loose the tube's warmth, but you gain wicked presence. I
never found the Z-Systems to be worse than the BAT VK5I, just
different. I will likely keep my RDP-1, but I doubt I would sell off my
reference Mark Levinson No. 380s preamp or the BAT VK5I. If I had a
lesser preamp I would definitely sell it to use the Z-Systems RDP-1
Righting your system's wrongs professionally.
Some music lovers are not interested in playing with EQ for program
material, which is a valid opinion. Yet you still need a Z-Systems
RDP-1 to get the most from your music system in your room. Music
playback systems are imperfect and listening rooms are even worse.
Professional acousticains are capable of measuring your room to
scientifically ascertain what are your sonic problems. He or she will
be able to tell you what kind of room treatments you'll need while at
the same time setting a basic EQ to elicit the best from your music
playback system. Professional acousticains are used to bring recording
studio playback systems up to speed, but rarely is this the case in a
music enthusiast's home. Using a Z-System RDP-1 and possibly some
tasteful room treatments you can improve your existing system
isn't much here. The three knobs on the faceplate are weird for me to
use, thus I only ever use the remote. Unlike adding a new pair of
speakers, a DAC or a preamp to your system, there is a learning curve
with the RDP-1 is. Considering the advantages a digital EQ brings to
the musical equation, the learning curve is well worth it.
It is rare when I encounter a single product that does so much to
positively effect the enjoyment of my music. The Z-Systems RDP-1 adds
digital volume control, high and low pass filters, 4 adjustable bands
of EQ plus the ability to feed your DAC up to a 24 bit, dithered
digital word. That is quite a value for $5,000. The RDP-1 is a very
competent digital preamp worthy of replacing many mid-level preamps or
in conjunction with any ultra high end unit. When you factor in the
ability to easily augment your music playback, while the lights are
dimmed and your attention is focused on your music, you realize the
true power of the RDP-1. It is a product that empowers you to make your
music sound the way that you want it to.
|Model ||RDP-1 Digital Preamp and EQ |