Insert the Z-ROCK anywhere in the signal path.
There are three things you can adjust:
1) EQ Level - fully variable from flat to boosted.
2) EQ Curve - two available equalization curves.
3) Bypass - a true bypass switch to disable the Z-ROCK.
Below is a graph of the less aggressive of the two available EQ curves.
The graph above shows the Z-ROCK EQ turned all the way up. The lower dotted line is what you get when the ZROCK is bypassed. As you can see, the blue line creates a linear shelf of bass between 20 ~ 60 Hz, followed by a gradual slope to 260 Hz where it flattens out through the midrange and then gently rolls the treble.
Remember this EQ is infinitely adjustable so if you want less bass and more highs simply adjust the EQ knob a bit.
WHY WE CREATED THE Z-ROCK
This long overdue product was
originally designed to make listening to classic rock on streaming internet radio a
less hateful experience on high end systems that have no means to
adjust frequency balance. Happily it is also usable in high fidelity settings and with any type of music.
It can be used to fix bass shy recordings, fix bass shy speakers or fix overly bright listening rooms or any combination of the three.
when classic rock was recorded... speakers were generally large and had
no shortage of bass. Receivers had a loudness button that in concert
with the bass and treble controls made listening to these recordings
more enjoyable. Also, music was analog which in general contains more
density. Fast forward to today where audiophiles are trying to listen to
classic rock mp3's streamed over the net on systems that have no tone
controls or loudness contour and you can see the problem.
The most commonly seen fix for this has
been to add a sub-woofer and turn it up a bit. Sadly the sub-woofer
often does as much damage as it does good, resulting in a sound that is
Even a perfectly executed sub-woofer will do nothing
for enriching the tone of the midrange which is also essential to
balancing an increase in bass. The truth is, you need help all the way
out to around 1 kHz. A sub-woofer usually stops at 100 Hz.
ZROCK shown with its 12AU7 tube removed
Unlike a loudness button which peaks the response at around 100 Hz, the Z-ROCK
creates a low frequency shelf which has flat response from 20 Hz ~ 60
Hz followed by a controlled roll off where things flatten out in the
midrange. In addition there is a subtle roll off above 10 kHz to remove
edginess. The result of this is an incredibly rich, full sound with big
increases in midrange tone. It animates the music rather well.
REASONS TO USE A Z-ROCK
The reality is that many speaker/room combinations will roll the low bass off leaving you with a leaner, drier, less rich sound. Below is the typical low bass performance found in many listening rooms:
When you combine typical low bass performance like that shown in the room above with a Z-ROCK you end up with a much flatter bass response in the bottom octave where many systems lack.
A Z-ROCK restores this missing information and makes your music sound full and rich at lower volumes. Rock music gains a nice "hit" that you normally don't get unless you're at a concert or club, and does so without having to be turned up loud.
DUAL EQ SETTINGS
The Z-ROCK has two built in EQ curves that have been crafted to accomplish the goal on two basic types of systems. Both are fully adjustable letting you "dial-in" just how much EQ you want.
The EQ switch is located on the rear. When the switch is UP it is using EQ-A and when the switch is DOWN it is using EQ-B.
EQ-A is designed for systems that characteristically sound lean. That is to say the speaker/room combination yields results similar to the graph above where bass is diminished.
EQ-B is designed for systems that have perfectly good bass when it's in the recording, but you want to listen to classic rock where many of the recordings lack bass at low volumes. EQ-B makes it possible to dial in a nice dry perfectly articulate hit without becoming too heavy.
Both of these equalization curves have been designed so that the "perfect sound" is obtained at about the 3/4 position on the dial. This way EQ-A can still be used to not only fix your room speaker issue, but still add bass when needed to lean recordings. EQ-B, while characteristically drier is also a steeper EQ slope capable of more bass boost, and more high frequency cut when turned up all the way.
BYPASS SWITCH makes it painless to use the EQ. This is because it lets you hear exactly what effect the EQ is having as you adjust it. It does this by letting you compare your EQ'd setting to non-EQ'd (flat) as many times as you want while you are adjusting the knob so that you hear exactly what effect it is having.
One of the reasons bass and treble controls and graphic equalizers died off with the rise of hi-end audio is because they were often done in such a way that they created changes in the phase angle resulting in a subtle but noticeable smearing of the sound. To ensure these side effects don't find their way into the Z-ROCK, we use a simple passive filter and a single-ended triode to restore the gain lost from the filter.
ZROCK shown with bottom cover removed
There is no negative feedback in this design and only a single tube with no circuit boards so transparency is extremely high.
Most users who showed concern about a Z-ROCK having negative effects on imaging and sound stage size reported that instead of getting worse, those things actually got better.
A Z-ROCK is appropriate virtually any time you wish there was more bass and more hit and better tone with less glare. This makes it possible to listen at lower volumes since the bass is not lost when the volume is turned down. It is also possible to listen louder in untreated rooms that are bright to begin with.
A SIMPLE PREAMP?
The Z-ROCK is not designed as a preamplifier, it is assumed that you will have either a preamp or amplifier with a volume control to actually adjust the volume in your system.
That said, the way the Z-ROCKs variable EQ knob was deigned is this: From 0 to 1/2 way, the control acts as a regular volume control with no EQ.
At the 1/2 way point, the output level and the sound exactly match the way the Z-ROCK sounds when it is bypassed.
From this 1/2 way point to 3/4, the sound will get louder and the EQ slope grows proportionately.
From 3/4 to full the EQ slope continues to grow and high frequency attenuation starts to becomes apparent.
Rear view showing input and output jacks, EQ Curve switch and fused power cord connector.
OPTIONS / Available in the shopping cart.
Voltage - Select the proper voltage for your country
Signal Capacitors - Select from 4 types of coupling caps shown below:
Coupling Capacitors aka Signal Caps shown left to right 1 ~ 4.
1) G.E. Film Capacitor -
Best for making mid-fi digital / analogue sound good.
2) Jupiter Cryo Beeswax - type I
Best for making hi-fi digital / analogue sound good.
3) Jupiter Cryo Beeswax type II -
Copper Foil for max resolution.
4) VCap Copper Foil -
Alternate choice for max resolution.
Knobs - You may choose from the following knobs.
Left to right is Black Ebony, Gold, Black Chicken Head, Cream Chicken Head, Rosewood.
RCA Jacks - Choose between Gold or Silver RCA jacks, both are precision made in the USA.
Note:choose the metal that matches your cables.
Left to Right are Silver and Gold RCA jacks.
If you purchase one second hand and
ever have questions or technical problems we WILL be happy to check it
out for you and service it if needed for a very reasonable rate.
have a support
many people who's experiences you may benefit
reviews on our products here.
|| 7 lbs. ea.
|| 2.5" H x 6"
W x 11.0" D
| Circuit type
|| Single ended
Class A Triode
| Input voltage
||15 volts max
|47 K Ohms
|Noise / Hum
|| -80dB / -62dB
|| 5 Hz ~ 90 kHz
|| ZERO negative
| Signal tube
|| 12AU7 / 5963
|| precision WW/MF
by DALE, VISHAY
| Signal Cap
| AC cord
|| Removable power
|| 13.5 watts at the outlet
Dec 2016 ~ July 2017 original model ZROCK
July 2017 ~ ZROCK2 with the fully adjustable EQ.
ZBOX - Flat response tube buffer stage that has no gain.
ZSTAGE - Flat response tube gain stage that has gain.
ZROCK front view showing level control, bypass switch, 12AU7 tube
30 DAY IN HOME TRIAL - 10% RESTOCK FEE