The Colossus H-100™ amplifier is a unique and diverse hand-built guitar amplifier. It consists of four channels, each with its own gain, tone, bright, and level controls.
The Clean channel produces a wonderfully warm tone that aims to be the best of any channel switching amplifier. Where most other high gains amps seem to include a clean channel out of necessity rather than desire, the Colossus has a no-compromises clean channel with its own dedicated preamp tube voiced specifically for huge headroom and sparkling cleans. With the included Gain control on the clean channel, one can also dial in a very cool fat distortion.
The Crunch channel is a great sounding medium gain distortion. With this channel one can easily play rock, blues, and country, and then take it over the top by engaging the second distortion mode. Like all the channels in the Colossus, the gain control for the crunch channel is usable over its entire range. It can even be dialed back to produce a clean sound at the edge of breakup, or cranked for a great rock tone. This channel is inherently touch sensitive and notes easily ring through the crunchy overdrive. It doesn’t compress the tone as much as the Lead channels giving a more natural sound. It also takes pedals wonderfully, infinitely expanding your tonal palette.
Lead 1 and Lead 2
One of the highlights of this amplifier is its two lead channels. The channels have identical gain structure, however they are voiced differently. Lead 1 has a bit more high-mid focus, whereas Lead 2 is a bit more low-mid. One can easily dial in a nice medium to high-gain rhythm tone on one channel and still have somewhere to go for solo cut in a band situation. Each of the Lead channels has independent gain (Mode) and response (Fat) mode switches, allowing four different tone shaping tools recallable via the front panel, foot switch, and MIDI CC or PC commands. The EQs of the Lead channels allow one to dial in a large range of tones, from quintessential 80s rock to death metal.
The Colossus includes a very transparent tube buffered series effects loop, including Send and Return level controls. When bypassed the entire tube buffer section is removed from the circuit. This ensures the dry tone maintains maximum punch and clarity when the loop is not needed. Further, if the customer desires to bypass the loop indefinitely, the V5 tube may be removed.
The preamp section of the Colossus is finished off with dual switchable master volumes to allow a boost or cut when selected. Finally, the Top and Bottom controls allow for high and low frequency negative feedback adjustment of the power section, similar to presence and resonance style adjustments found on other amplifiers. The Bottom control is especially useful for dialing in the low end ‘thump’ specific to your cabinet.
The output power varies between 100 and 120 watts RMS, depending on the tubes installed. A number of different tube types are compatible with the Colossus and can be easily installed after a simple bias using the built-in test points and inexpensive DMM. In fact, the adjustment pot and test points are both available outside on the outside of the amp, therefore it’s not even necessary to remove the chassis when changing tubes!
Switching and Control
For maximum flexibility, each channel selection, distortion and fat mode change, master volume select, loop bypass, and mute functions are all switchable via a number of methods. All of these functions are controllable via the front panel. Further, all are also available via the RCI™ (Rhodes Custom Interface) and MIDI interfaces for foot switch control and system integration.
RCI™ (Rhodes Custom Interface) Overview and Example
RCI™ is an innovative means of connecting any number of KSR Amplification products for synchronization and control. Unlike MIDI, RCI™ is bi-directional, allowing for devices to communicate in both directions. As a simple example, take a Colossus amplifier and connect it via MIDI to an effects processor and generic floor controller. The Colossus was setup to change amp channels for different presets using the convenient MIDI Learn function. The Colossus foot switch is connected to the amp via RCI™. With this simple rig you can manually change channels with the amp foot switch or amp front panel, and say Channel 1 (Clean) is selected. If you select a patch with the MIDI floor controller that engages Channel 3 (Lead 1) and turns on the effects loop, the foot switch will also turn on its Lead 1 and Loop LEDs to reflect the new setting! Of course, the amp front panel updates immediately as well.
To take this example to the next level, let’s remove the generic MIDI floor controller and replace it with the KSR Amplification M/20 controller equipped with RCI™. With this setup we will still keep the Colossus foot switch, and it and the M/20 will be daisy-chained with an RCI™ cable. At the other end the RCI™ cable connects to the Colossus and an additional piece of gear, the KSR Amplification 8 channel loop switcher. This single cable supplies power to both foot switches and moves the data signals between all four RCI™ equipped devices. Once all these KSR Amplification devices are connected together, things start to get interesting. The M/20 is the brains behind the operation and it stores patches containing amp settings, loop switcher settings, and MIDI settings. To create a new patch simply select the amp settings with the amp foot switch or front panel, turn on the desired loops with the M/20 or loop switcher front panel, and press Store on the M/20. Now, a patch has been created from a snapshot of all these settings! Simply repeat this process for other channels, effects, modes, etc, it’s that easy. If once a patch has been stored you change a setting, such as the amp channel, RCI™ will signal the change to the M/20 and it will blink its Store LED indicating the patch has changed. If you simply hit Store, this change has been saved! Each preset will also store any number of MIDI PC or CC commands to be sent in order to setup MIDI enabled. With the contact closure capability of the 8 channel loop switcher, one may also output the M/20’s patch based tempo as an automatic tap-tempo output.
We’ve recently updated the firmware of the Colossus foot switch to make it more intelligent. To see how it handles both direct control of the Colossus, and storage of presets, check out this video:
Any KSR Amplification device that has both MIDI and RCI™ ports is also guaranteed to broadcast MIDI information. This means you can connect MIDI devices to your M/20 controller at your feet that will also be linked to MIDI devices connected to an amp or loop switcher in the rack. Since the RCI™ cables are capable of transmitting data at least 250 feet, the hardware can also function as a MIDI repeater of sorts.
With the current RCI™ protocol up to 255 KSR Amplification devices may coexist on the bus at a time. This includes amplifiers, loop switchers, floor controllers, etc.
Channels 4 – Clean, Crunch, Lead 1 and 2 (lead channels are completely independent with identical gain structure, however voiced differently)
EQ 3 band EQ per channel
Distortion Mode Switch Channel 2 (Crunch), Channel 3 (Lead 1), and Channel 4 (Lead 2)
Fat Mode Switch Channel 3 (Lead 1) and Channel 4 (Lead 2)
Channel 1 (Clean) Controls Gain, Bass, Middle, Treble, and Level knobs; Bright and Channel Select switches
Channel 2 (Crunch) Controls Gain, Bass, Middle, Treble, and Level knobs; Bright, Channel Select, and Mode switches
Channel 3 (Lead 1) Controls Gain, Bass, Middle, Treble, and Level knobs; Bright, Channel Select, Mode, and Fat switches
Channel 4 (Lead 2) Controls Gain, Bass, Middle, Treble, and Level knobs; Bright, Channel Select, Mode, and Fat switches
Master Controls Master Volume 1, Master Volume 2, Top (Presence), and Bottom (Resonance/Depth) knobs; Master Volume Select switch (hold to toggle loop bypass)
Foot Switch Custom 7 button with multi-colored indicator LEDs, RCI™ (Rhodes Custom Interface), Controls Channel 1-4 select, Mode, Fat, Loop, Master, and Mute
Remote Controllable Functions Channel select, all distortion modes, fat modes, master volume select, loop bypass, and mute
Control Options Front Panel (loop bypass toggle by holding MV select), RCI™ (Rhodes Custom Interface), and MIDI
MIDI MIDI Input and Output / Thru
MIDI Channel Omni or Selectable, only for CC control
MIDI Control PC patch learning and direct CC control of individual functions
MIDI Programming Automatic patch learning — setup for desired patch, press the Learn button, and transmit a MIDI PC to associate with that patch
Bias Test Points Measure with any DMM capable of DC millivolts, 1 mV = 1 mA of plate current, assume 460 plate volts
Bias Adjustment Pot Location On top of amp chassis, near left most power tube. Guaranteed to bias properly with EL34 or 6L6 tubes
Output Power At least 100W with quartet, 50W with duet (two tubes removed)
Output Impedance Switchable between 4, 8, or 16 ohms
Cabinet Dimensions 26.5″ L x 10″ W x 10.5″ H (excluding handle and feet)
Weight 45 lbs
Shipping Dimensions 32″ L x 16″ W x 16″ H
Shipping Weight 54 lbs
Weight: 54 lb.
Dimensions: 32in. × 16in. × 16in.