Knucklehead Series
control and a three-band EQ; pulling the midrange knob scoops the mids.
Other features on the front panel include high- and low-gain inputs and controls for presence, sub level (which functions when the Knucklehead is connected to a Rivera subwoofer and focus. This latter control is rather amazing: it allows you to alter the speakers' response from loose to tight. This is
especially useful for matching to players' styles and various speaker and
cabinet types.
The features and tone options don't stop on the control panel. The back
panel has a low impedance-buffered series-parallel effects loop with controls
for send, return and blend There are also two speaker jacks, a subwoofer
output, a recording output and a three-position impedance selector. A standard MIDI input and output are Provided, and there's a separate input for the
Rivera MIDI Headmaster footswitch. Tone and power can be altered using
die vintage/modem power switch, which toggles between triode and pentode
output, and the high/low power switch, which cuts the wattage in half. In the
triode/low power mode this beast can actually be tamed to a tasty 12 watts!
Sound Department
We tested the EL-34- and 61-6-equipped Knucklehead amps with a Rivera
Vintage 30-loaded 4x12 and the 500-watt powered Los LobottoinSub 2,
which can operate in full-range or highpass modes. The basic difference
between the two heads is in the midrange. While the 6L6 version has a near
perfect balance in all channels, the EL-34 model delivers undeniable chime
and vocal attack. I preferred to run the subwoofer in high-pass mode, so that
the true lows reached it. Whether at low or high volume, this hefty cabinet
adds an addictive dimensionality and depth that will complement any style.
The Knucklehead's first channel, through abundant EQ and power options,
creates tones that range from sparkling clean to tweedlike overdrive.
Channel 2 covers everything from driving blues to hard rock, bringing British
grind and crunch to life, with some of Rivera's own spice giving the highs
added zing. The third channel goes right for the throat, with chainsaw
aggression and nail-spitting drive. Boasting a dynamic response and plenty
of cut, this is easily one of the most terrifying and playable ultrahigh-gain
channels available. The only flaw is the Knucklehead's short tank reverb,
which accentuates the highs rather than affect the entire spectrum.
Ultimate Short Stack
KR-100 6L6 Top with K412T and Sub 2
100+ Watts, 4-12” Vintage 30’s, 500W 2-12” JBL Powered Sub
Sonic Boom
Rivera Kuncklehead Reverb with 4x12 and Lobottom Sub 2
By Eric Kirkland
The Rivera Knucklehead Reverb blazes a new trail for high-gain heads with
a remarkable clean channel, load-, of features, an intelligent user interface
and MIDI control. Add in the thunderous Sub 2 and you've got a massive
tone delivery system with an unmatched sonic footprint.
Guitar World - Feb. 2003
3 Auxilary TRS DPDT
Relay Switches for
other amps and effects.
Regulated 12VDC-100Ma.
outlet for powering
your stomp boxes.
There are a lot of high-gain heads on the market, but few of them can create
more than one useable sound. The Rivera Knucklehead Reverb is a fullfeatured tone machine that allows you to control practically every aspect of its
performance using its host of sound and power options, built-in MIDI control
and three uniquely voiced channels. For foundation-shaking bass, the Los
Lobottom Sub 2 delivers a colisum-crumbling low end that redefines the guitar's role and presence in the mix.
Peer through the Knucklehead's metal grille and you'll we the four 6L6s and
five 12AX7s chat create its 100 watts of sweet tone and immense distortion.
In addition to the rocker-style power and standby ,witches, the front panel has
a row of knobs, nearly each of which has a push or pull option. Each channel
has gain and master controls and is activated by pushing the appropriate
gain knob Pushing the master control each channel engages the boost.
Channel 1 has its own bass, middle and treble controls, and pull knobs for
brightness, notched midrange and contour. Channels 2 and 3 share a reverb
6 User Programmable
and assignable switches, arranged
in 5 banks, with 16 simultaneous
MIDI program change commands
Self-Powered by the
Knucklehead Reverb
MIDI Out and
KR Amp Connection
using standard
5 Pin MIDI Cables
Convenient Bank selection
Easy to Program
3 Digit 8 Segment
Super Bright Display
Reverb 100
The Kuncklehead Reverb features a PC board layout with board-mounted
sockets for the five 12A7s and four EL34s. Preset boost levels can be adjusted using three trimpots on the motherboard.
switches combine to yield four power levels: High/Modern, 100 watts;
High/Vintage, 50 watts; Low/Modem, 25 watts; and Low/Vintage, 12 watts.
Super Sounds
The review amp was the 100-watt with EL34 tubes (50-watt and 6L6equipped versions are also available), driving a Rivera K412T 4xI2 cabinet
($995 retail/$799 street). I put the Knucklehead Reverb 100 through its
paces using a '68 Les Paul Custom, a late-'70s Strat, and a mid-'90s PRS
Custom 24, and the amp sounded really good with all of them. The tone
controls are beautifully voiced, and the many push/pull variations provide
an extremely wide variety of sounds. Despite the plethora of options, however, I was able to dial in perfectly satisfactory sounds quickly and easily.
Compact Massive Attack Stack
KR-55 EL-34 Top with KS-312
55 Watts, 2-12” Celestion Vintage 30’s,
300W 1-12” Powered Sub built in.
Bench Test
By Barry Cleveland
The Knucklehead Reverb 100 ($2195 Pro User Net) expands Rivera's
basic concept of offering classic American and British tones by adding a
third preamp channel. Channel one provides Fender-like clean tones, channel two takes you into Marshall/Hiwatt territory, and channel three soars
into the upper reaches of supersaturated sonic meltdown.
Gobs of Knobs
The Knucklehead Reverb is definitely not for knuckleheads. There are 17
knobs on the front panel alone-nine of which change function when pushed
or pulled-for a total of 23 controls. Some of these knobs are organized in a
less- than -intuitive manner. For example, the bass, middle, and treble controls are arranged from left-to-right in one section, and right-to-left in the
other section.
Each of the three channels has separate controls for master and gain levels, and a switchable boost mode. There are also two sets of tone and
reverb controls: one dedicated to channel one, and another common to
channels two and three. The bass, middle, and treble knobs in each tone
set affect the level of the frequencies- so turning a knob completely counterclockwise removes that frequency entirely. Additionally, most of the tone
knobs are the push/pull variety, allowing them to do double-duty. On channel one, pulling the treble knob adds brightness, pulling the middle knob
engages a notch fliter (which thins the sound slightly), and pulling the bass
knob adds contour (richer bottom). Similarly, the middle knob in the channel two /three section engages some thing called Scoop, which does not
"scoop" the mids as you might imagine, but rather deepens the midrange
notch frequency from 750Hz to 550Hz, which is supposed to simulate the
tonal character of a Marshall plexi
Back Issues
The Knucklehead Reverb's rear panel is also packed with features.
Highlights include a High/ Low power switch that cuts the output power in
half, and a Modent/Vintage, switch. The Modern setting puts the amp in
Pentode mode, for a clean and bright sound with lots of headroom and odd
harmonics. Vintage puts the amp in Triode mode, which increases the even
harmonics for a darker sound, and cuts the power in half. These two
Channel one produces clean tones reminiscent of old Fender amps, and it
even breaks up like a vintage Deluxe when you crank the gain. Overall, the
sound is rich and well-balanced, with a warm and tight low-end and lots of
sparkle in the highs. The tone controls are quite effective over a wide range,
and the notch, contour, and bright modes all provide additional usable timbres. My favorite channel one option was the darker sound of the
vintage/triode mode. it should be noted that the overall volume of channel
one is considerably lower than that of the two overdrive channels.
Channel two produced some amazing distortion tones. Here, the amp can
wail like an old non-master 50-watt Marshall with its controls maxed-out,
sing like a '60s Orange head a la Peter Green, and create the spongy, yet
clearlydefined, crunch of an early-'70s Hiwatt 100.
Channel three offers a similar array of tones, but with increased saturation
and a nastier highend. Some of the sounds reminded me of a pumped-up
Soldano SLO, while others had an almost fuzzboxy square-wave quality.
The Knucklehead Reverb also can be used as a recording preamp-sans
speaker cabinet-by switching it into standby mode, and taking the signal
from the recording output (post-EQ, reverb, and effects loop), the effects
loop send (post-EQ and reverb with send level), or the sub output (post-EQ
and reverb with send level). None of these outputs provides speaker emulation, but it's definitely a boon to do "silent" direct recording in standby mode
without having to worry about maintaining a speaker load (and dealing with
the resulting volume issues).
Under Foot
The Knucklehead Reverb is designed to work with the included FS-9
Head Master MIDI footswitch, which can be programmed to change channels, activate boosts, switch the effects loop in and out, and turn the reverb
on and off- individually or in programmable combinations-as well as send
program change messages to external MIDI devices. The Knucklehead
Reverb also responds to MIDI messages from other external controllers via
its MIDI input (but not while it's connected to the FS-9). The Head Master
doesn't allow you to name programs, however, so you'll have to keep a list
of which program numbers correspond to which sounds.
Knuckle Up
A great-sounding professional amplifier that is loaded with enough sonic
options to satisfy even the most inveterate tone-tweaker, the Knucklehead
Reverb is also powerful enough to hold its own in nearly any performance
situation. In addition, its MIDI capabilities will be welcomed by users with
sophisticated rigs who want the convenience of having several preset
sounds without sacrificing genuine tube tone.
Knucklehead Reverb 100 Head Review, as seen in Guitarist UK, June
2003. Rating “5 Stars Guitarist Choice”
Rivera’s Knucklehead Reverb packs more wallop than a prize-fighter,
and looks prettier than most of them too
by Nick Guppy
The rear-placed MIDI section offers two inputs (one MIDI standard, the
other with phantom power for the Rivera’s Headmaster MIDI pedal packages with the Knucklehead), a MIDI out/thru, and a small rotary channel
selector labeled 0-15. Why? Rivers has adopted the more common 1-16
approach for the numbering its MIDI channels, but unfortunately the switch
manufacturer hasn’t so you have to add a 1 to each channel on the switch
to get the correct MIDI channel. It’s an annoyance, but a minor one as this
switch isn’t likely to be changed often.
Paul Rivera deserves a lot more recognition on this side of the Atlantic
than he presently enjoys.
Since the early eighties he’s been producing amps under his name,
although his history goes back a lot farther than that. At Fender he codesigned a number of circuits, including the 1980 Fender Concert Modelone of the best point to point designs to leave the Fender Fullerton factory,
and regarded by many as one of Fender’s best modern amps. Over the last
two decades though, Rivera Research and Development has provided some
pretty amazing designs of its own, and the Knucklehead range is typical of
Paul’s approach that blends uncompromising quality and flexibility with a
logical control layout that puts the player in the driving seat.
Housed in a plywood sleeve almost as wide as a standard 4x12, with no
less than 17 knobs on its full-width control panel., the Knucklehead is an
imposing beast. Through the metal grille, you can see the two enormous
transformers that hint at the power it can deliver, as does the physical effort
needed to pick it up: it weighs more than many 2x12s.
Inside the chassis there’s a lot of densely packed electronics housed on
several large PCB’s, which are all double-sided and through plated for maximum reliability. As well as the opto-isolators used for channel switching (a
Rivera hallmark) there are several relays, and all interconnecting leads are
neatly bundled and tied back.
With Channel 1’s boost engaged, the Knucklehead really sings-especially
with the humbuckers. Balancing the master and gain controls is the key to
getting the most out of this channel, and with the rear panel switches set to
“low” and “vintage” for around 12 watts output, this one can really be wound
up for maximum effect-even in a small club.
Channel 2 is the Knucklehead’s British voiced side with a completely different distortion tone that begs you to turn up and dig in. Whatever your
needs are in the distortion department you will find it here, from sweet classic rock through to ultra modern sustain with massive crunch. The bottom
end is huge-even more if you use the Sub-output to power a separate cab.
Rivera amps are renown for having a multitude of knobs to play with and
the Knucklehead is no exception. This is a proper three-channel design with
multiple voicing features and it definitely needs more than a cursory glance
at the well written manual to get the best of it.
Starting on the right, next to a pair of high and low sensitivity input jacks, is
the Knucklehead’s American-voiced Channel 1 with controls for gain, bass,
mid and treble, and a master volume. All the knobs on this channel have a
secondary function. The push/push gain control doubles as a channel
select, the treble control has a pull-switch marked “notch”-which changes
the mid-range frequency center point from 550 Hz to 250 Hz-and the bass
control has a pull switch called “contour” to accentuate low end wallop.
Finally, Channel 1’s master volume has a push/push switchable boost which
combines with a special EQ circuit to sweeten the tone as well adding a lot
more gain.
Channel 2 is the Knucklehead’s British-voiced side. Again there are controls for gain, bass, mid and treble and a master volume, with secondary
functions for the gain control (channel select), mid-range (a pull scoop
switch that dips the mid notch to 750 Hz) and a push boost on the master
volume. Channel 3 shares Channel 2’s EQ circuit, but has separate gain
and master controls, again with channel select and boost functions. Finally,
there are two reverb level controls for Channel 1 and Channel 2/3, followed
by controls or presence, focus (another Rivera hallmark, this one varies the
loudspeaker response form tight to loose) and a sub level. This last control
activates a variable high-pass filter and diverts low frequencies to a subwoofer output on the rear panel, where they can be send to a separate powered cabinet, like Rivera’s LB-212.
The rear panel is just as busy. There’s a pair of variable-level send and
returns for the Knucklehead’s series/parallel effects loop, and a loop blend
control with a bypass switch. Then we have hi/lo output power switching and
vintage/modern (pentode/triode) switching, and a recording output and that
separate sub-woofer output.
And just when you thought there was nowhere else to go, there’s Channel
3. It kicks in another distortion stage and a texture that’s a lot more in tune
with modern rock and nu-metal. Despite sharing the same EQ
As Channel 2, this channel has a completely different vibe that’s nastier
and way more aggressive.
With so much compression, you’d expect it to be hard to keep a wide
dynamic range but the Knucklehead manages to do both brilliantly. At full
power it’s phenomenally loud, with a clarity and definition that leaves many
other so-called “super amps” looking rather bland by comparison. The
spring reverb effect-on all channels-is surprisingly full, adding only minimal
noise as the levels are turned up.
If you’re still with us, you’ll realize that compromise isn’t a word Paul
Rivera uses. Happily, despite such a complex layout, the Knucklehead’s
controls are logical and easy to understand on a basic level.
The American-voiced Channel 1 is full of tone. Like other similar Rivera
designs, this channel tales a little effort to dial in, but when you get it right
it’s hugely rewarding. Massive headroom for shimmering clean sounds is
just one of this channel’s benefits, and by juggling the contour and notch
switches you can call up any number of vintage and modern tonalities with
more than enough gain for lead work.
Adding MIDI into the equation really puts the Knucklehead into a class of
its own. With Rivera’s Headmaster footswitch you can use MIDI to change
channels, select boost and toggle the effects loop in or our as well as controlling up to three non-MIDI amps using the Headmaster’s built in relay
switching, and send program changes to MIDI effects units. With 30 patches on tap, and clever extras like an auxiliary DC power output to power
stompboxes, the Headmaster-plus-Knucklehead can easily become the
nerve centre of a complex multi-amp, multi-effects setup. Alternatively you
can just plug in a cab and a guitar and go for it on the simplest of terms.
Either way, amp and pedal perform superbly, with no pops or clicks and
minimal background hum.
Yes, it’s a very expensive purchase but the Knucklehead really delivers. By
comparison, some other amps in this price bracket are much harder to justify. Every feature is onboard for a specific reason and adds something.
What we’re really trying to say is the Knucklehead Reverb is one of the
world’s ultimate guitar amplifiers; once you have one, chances are you will
want to hang on to it for a very long time.
RIVERA RESEARCH AND DEVELOPMENT •13310 Ralston Avenue • Sylmar CA 91342 • 818 833-7066 • fax 818 833-9656
E-mail : • Internet Site
New Products
& Reviews
Summer 2003
Rivera Announces
Routmeister For immediate release
Plugging a guitar straight into an amp delivers great tone, but adding
effects devices can severely degrade it. Enter Rivera's Routmeister, which
manages up to 12 effects between a guitar and one or two amps while
maintaining great tone and punch. The Routmeister works with mono and
stereo processors, and controls (and can be controlled by) MIDI gear.
Programs for switching effects in and out and generating up to 16 MIDI
commands at once are arranged in nine memory banks. Six program-select
buttons and two bank selectors, allow fast access to a total of 54 combination programs. The entire set of programs can be loaded from or saved to a
computer using MIDI System Exclusive messaging, and Windows-based
editor software is included.
Housed in a durable steel enclosure, the Routmeister has heavy-duty
footswitches and uses a ±15 volt power supply to ensure a wide dynamic
range. Its switchable input buffer deals with impedance loading from a guitar, and automatic ground-shorting in unused effects loops ensures noiseless operation. Dual premium-quality isolation transformers at the outputs
assure that the signal reaching the amp will be clean, punchy, and at a good
July 10, 2003
Highlights include:
• Two selectable inputs with bypassable input buffer.
• Tuner jack.
• Simultaneous control of routing for four mono and four stereo effects and
two amps, or eight effects and one amp.
• Eight effects loops in Chain 1, four effects loops in chain 2
• Up to six Routmeisters can be connected together, for a total of 36 buttons
and 72 programs.
• Sends MIDI program-change commands to any MIDI device.
• Acts as either MIDI master or MIDI slave.
For further information, contact Rivera Research & Development, 13310
Ralston Ave., Sylmar, CA 91342 USA. Phone: (818) 833-7066. Fax: (818)
833-7066. Email: Web site:
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