Rodenberg / Flexamp III Combo / Amp
FLEXAMP III Combo Front panel - handling/sounds/stage board
*All tube amplifier - 100W/120W
*3 totally independent channels, each with a second switching option
*=6 channels
*Each preamp stage has its own input stage vacuum tube
*10x12AX7, 1x12AU7, 1x12AT7, 4x6CA7 or 6550 or KT88
*(other main amplifier tubes 6L6, EL84, 6V6GT on request)
*Channel CH1B - internal GAS exiter
*Second switchable Master/Presence controls
*Muting Channel
*Deep control
*Reverb control - Accutronics Reverb (optional)
*Stage Board with 9 footswitches =CH1 / CH1B / CH2 / CH2B / CH3 / CH3B
*Master 1 - Presence 1 / Master 2 - Presence 2 / Mute
*Connection between Stage Board and amplifier by a standard XLR
*microphone cable
*All switching options of the stage board can be activated by the amplifier
*panel also
*Sounds: Standard FLEXAMP III
*CH1A - Clean Channel - vintage /warm - blues
*CH1B - Clean Channel - GAS exiter - modern to funky clean
*CH2A - Cruch / british
*CH2B - HOT ROD / more Gain and rough
*CH3A - Lead / smooth Lead sound
*CH3B - Lead + / creamy Lead sound + more Gain
*Custom Shop - individual sounds from Funky Clean up to Ultra Lead
*Jewel Lights for Power (red) and Stand By (green)
FLEXAMP III Combo - rear panel
*Illuminate Power switch
*Input power switch 115/230/240 (USA/Europe/Japan)
*IEC power input jack - main fuse - anode fuse
*Standard XLR jack for the Stabe Board connection
*Midi Interface IN/OUT - Learn
*Wattage Output control in 6 steps from 100 to 10 Watts
*Preamp Out / Main In jacks
*Serial or parallel Fx-loop with Mix control (parallel)
*2 output jacks - 4/8/16 Ohm - to box
*Direct Out with Level control
FLEXAMP III Combo- Special Features / Front Panel
One of the most important feature of the FLEXAMP III Combo amplifier is that all three channels are totally separated in the preamp section.
Each preamp stage has its own input stage vacuum tube, so the amp has
3 real channels.
7x12AX7 are working in the preamp section, 1x12AU7 - 1x 12AT7 - 3x12AX7 are working for reverb (optional), Fx-loop, and the main amplifier section
+ 4x output tubes.
The FLEXAMP III has no IC's or transistors in the signal path, exept the
channel CH1B with its GAS Exiter. The reverb amplifier uses 2 1/2 tubes,
the fx-loop is also powered by tubes only.
Each channel can be controlled by Gain, Bass, Middle, Treble and Volume controls. Beside than each channel has a second switching option. On the front panel you will find 3 rocker switches with two switching functions.
Pushing the rocker switches down will activate channel 1-3, pushing the
rocker switches up activates a boost function. In channel 1 a GAS exiter
will be activated.
The channels work in 'bolt' mode, means you can activate one channel by
pushing the channel switch. If you want to change to another channel you simply push the switch of the next channel, without switching the previous channel off.
So you can dial between the channels easily and fast, without switching
one channel off.
All 6 switching functions can be controlled by the stage board also.
The amplifier has also a double Master Volume/ Presence control section which can be activated by a rocker switch in the middle of the front panel
(pressing down - Master/Presence Control 1, pressing up Master/Presence Control 2) and by the stage control.
The FLEXAMP III Combo includes a Muting Mode which is activated by a rocker switch on the front panel beside the input jack or by Stage Board also.
It works in 'bolt' mode, means to return to a channel you simply push the switch of one channel 'on' without pushing the mode switch 'off' - this works automatically.
Beside the Master Control Section you can find the Reverb and Bottom controls. The reverb is driven by 2 1/2 tubes, not by integrated circuits and works with a Accutronics spring.
The Bottom Control raises the lower frequencies in the main amplifier.
All words (Gain, Bass, Treble...) are lasered into the stainless steel panel and are illuminated from behind when active - the same with the Stage Board.
Two Jewel Lights show the status of FLEXAMP 3 on/off and Stand By on/off
FLEXAMP III Combo - Special Features / Rear Panel
On the rear panel you can find the Main Input Switch, the switch for 115/230 volts and two Fuse Holders.
Beside that is the XLR Stage Board connection and the Midi Inferface with Midi In and Out, Midi channel selection and Midi Learn switch.
The cable connection for all 9 switching functions of the Stage Board is done by a standard XLR microphone cable.
Beside the Midi Section there is another main importand thing ot the amplifier. Witch a 6 position rotary switch you can reduce the output power
of the amplifier form 100 to 10 watts. This circuit is a totally new design and works direct in the main amplifier section.
It follows the Preamp Out - Main In jacks which is a signal cut between
pre- and main amplifier. The FLEXAMP III Combo has an active tube driven fx-loop with Send and Return jacks. With a rocker switch on the rear panel you can choose between serial or parallel mode of the Fx-loop. In parallel mode a Mix Control - Dry/Wet - is active.
The output jacks are wired parallel, with a 3 position rotary switch you can choose between 4 / 8 / 16 impedance load. The last jack on the rear panel is the Direct Out with Level Control.
The Output Stage of the main amplifier works with one 12AX7, one 12AU7
and 4 power tubes - here you can choose between 6CA7, 6550 or KT88 output tubes. The rocker switch for this selection can be found on the top of the chassis beside the power tubes.
The complete chassis, the front / rear panel, the rear and top grills are made of high grade stainless steel. The Input Power is fed by a Outsized Toroidal Transformer. All internal components are of high quality - only selected and caps (Orange Drops) and resistors are used.
This is a short summary of the features of the new FLEXAMP III Combo
RODENBERG amplification, Germany 
Hello,
this is Ulrich Rodenberg,let me tell you something about me, my work and products.
At the age of 13 I began to play guitar and used several old tube radios as an amplifier, this
sounded great (lol). Three years later at the age of 16, after 5 weeks of holiday work, I bought my first JCM 800 in 1984. Although it was and for sure is one of the best amplifier they made, the flexibility was very small for me. Because I had some experience in electronic, in fact I loved it, I built in a second master control switchible by stage board. The second step was to built in the circuit board of the real TS-808 for more gain. I played this modified amplifier two years in my band before I began to study how tube amplifiers really work. The very end was that my JCM was divided in pieces, the chassis and the top was gone to waste - how strange!
I used the transformers, choke, caps to build my first main amplifier in 3 rack space. I had just finished my high school exam in electronics and after 3 years more I finished my education as an electrical engineer.
In 1991 I started up my own business building several Pre- and Main Amplifiers, Heads, Combos and did repair jobs and modifications of everything a guitar player can use. In that time my second job was to
develop medical technologie circuits where I learned to work with microcontrollers and IC's - hard and software.
In 1996-98 I introduced my All Tube Guitar Head, with Motor Driven Pots, 200Watts, fully programmable which was called 'The Most Special Amp' at
Frankfurt Fair! After a 5 year break in building amplifiers I went back to business in 2001 to put my experience of the last years into a new amplifier series. During that time in 2005 a friend asked me to build a real good sounding overdrive pedal and it won't take long the whole GAS-Overdrive
family was developed. The top was when Lee Ritenour stumpeled into the GAS pedals and asked me to build the Official Lee Ritenour LR-GAS. I had designed and built this pedal within only 3 weeks and the LR-GAS was ready to use it on Lee's Asia tour in Nov. 2006
All the time I worked on my new amplifier series too, but the main change in my amp design was to built up amplifiers which uses only vacuum tubes in the signal path, no IC's or something else but IC's and microcontroller only for the internal switching system and Midi. In December 2006 I finished this amplifier series which features 5 completely seperate channels with 22 vacuum tubes - really strange.
For those who do not like Big Heads I developed a smaller 3 channel guitar head with 16 vacuum tubes, in fact this is as big as the biggest amps on the market - I cannot do it smaller (lol).
Today, at the age of 41, I can say these are the most flexible and best sounding amplifiers I've ever made! - more to follow...
Ulrich Rodenberg
