Bogner Atma 3-Channel 18 Watt Guitar Amp Head
The most versatile and ultimate bedroom to stage amplifier that goes from 1 to 5 or 18 watts full tube power without sacrificing tone and feel. Where old tradition morphs into new and iconic tools are re-envisioned for the modern hand. This is Atma.
The sleekly rounded corners are perhaps the first detail noticed of Atma’s unique hybrid aluminum and wood construction. Not only is it a beautiful artistic statement that’s incredibly strong and durable but it also delivers detailed midrange and tonal clarity. Light weight, portable and evolved, the sophisticated Atma is equally comfortable on a greasy juke-joint stage or penthouse apartment over-looking the shimmering & pulsating lights of any metropolis.
Within Atma you can feel the influence of Reinhold Bogner’s grandfather, who owned an aluminum factory, as well as his respect for famed industrial designer Dieter Rams. This was the modernist era of air-stream travel-lodges, glass walled homes and experimental materials used on futuristic concepts. And once again, past design ideas and approaches are being challenged and pushed forward by Reinhold Bogner and Atma.
The Atma has a single high impedance input located on the front panel.
CL/CR/SO Toggle Switch
This switch lets you select one of the three channels if no foot controller is connected. The front panel display lets you know which controls are active. Whatever control is illuminated at a certain channel setting can be used to alter the sound.
60/70/80 Toggle Switch
This 3 position switch works on the crunch and solo channel and will give you the option to find the right gain structure for guitar, pickups, and musical style.
60 – Produces lower gain plexi and bassman tones, you have to set the gain high for overdriven sounds otherwise the amp stays pretty clean which of course gives you the option to use it as a second clean channel as well. This voicing works well in combination with high volume settings for dynamic cranked power-amp overdrive.
70 – Bumps up the gain and slightly narrows the frequency spectrum to give you a more focused high gin sound
80 – Has the most gain, due to the high compression the volume gets cut and needs to be readjusted. This mode is also good for very low volumes.
This control sets the amount of gain for the crunch and solo channel.
Located on the back panel you find the CR gain control. This one lets you preset the crunch gain, which is the difference in gain between the crunch and solo channel. with this control turned up all the way the crunch channel has essentially identical gain as the solo channel. This is useful if you would rather have channels with identical gain but want two different switchable volume settings.
This control attenuates the tone and gain characteristics of the clean channel. A lot of thought has been put into the design to have a very flexible clean channel with just a tone-, volume control and a bright switch. It is best to start out with it set half way and see it as a neutral position. From there if you turn it down, you will get less gain with more highs and bass for the typical scooped blackface sound. Turning the control up will add gain and midrange growl reminiscent of the classic tweed tone.
Bass, Middle and Treble Controls
Let you control the bass, middle and high frequencies of the crunch and solo channe
These controls let you set the loudness of each channel independently from each other.
This switch lets you choose a dark, neutral or bright position and works for the clean channel only. Note the higher the clean volume is set the less effective the switch becomes.
Power Indicator Light
This light indicates that the amp is powered on, it is also sensitive to the input level and will flash along with your strumming dynamics.
Power Cable Socket – Back Panel
This socket connects the Atma to the main AC voltage, it is recommended to have the power switch in the off, zero (0) position. Plug the supplied cable first into the amplifier and then into your wall AC socket. Make sure your amplifier is made for the correct voltage of your location. The power cable socket also has a little pull out fuse holder, it contains the main fuses. To pull the fuse holder out, you must disconnect the power cable first; use a little screw driver to pull the holder out. Please note it does not detach from the socket. The holder comes with two fuses, the inner one is the actual one used while the outer one is a spare.
Power Switch – Back Panel
After connecting a speaker cabinet or other load and with the power cable connected you can turn the power on, flip it from 0 to 1, the pilot light on the front will light up. Please note the Atma has no standby switch, to extend tube live we recommend to have the vintage/modern switch set to vintage so the EZ81 rectifier tube is engaged which will raise the voltage very slowly and therefore protect the tubes and filter capacitors from voltage peaks.
FX Loop – Back Panel
The Atma has a buffered series effects loop between pre and power amp. Connect the send to the input of an effect and the return to the output. The loop circuit is completely out of the audio path as long as nothing is plugged into the send jack. The send signal still feeds directly into the power amp as long as nothing is plugged into the return jack. This can be useful if you just want to send the preamp signal to an external power amp etc….
Vintage/Modern Switch Back Panel
This switch is in the power amp circuit and lets you have either a wide open dynamic – vintage or a more dense and tight modern – response usually preferred for higher gain rock tones. In the modern setting it also turns off the tube rectifier which is helpful in case the EZ81 rectifier tube is bad. We recommend to set the switch to vintage at the time you turn the power on, then wait 20 seconds before you switch to modern, see the “power switch” topic.
Power Attenuator Switch – Back Panel
This switch gives you three power settings, in the middle position you have the full 18 watts for maximum headroom. From there you have the choice to set it to 5 or 1 watt.
FT.SW. Foot Controller – Back Panel
Plug here the foot controller in. You have two switches, the right one lets you switch from clean to overdrive (led illuminated), the left one lets you switch between the solo and crunch (led illuminated) channel. If you switch from the clean channel to the overdrive, it will depend on the left switch which one of the two overdrive channels is on.
CR Gain – Back Panel
As previously explained above, the cr gain control lets you preset the crunch gain, which is the difference in gain between the crunch and solo channel. With this control turned up all the way the crunch channel has essentially identical gain as the solo channel. This is useful if you would rather have channels with identical gain but want two different switchable volume settings.
Speaker Outputs – Back Panel
You have the choice of 16, 8 or 4 ohm output impedance; please use the value which matches your speaker cabinet. A speaker or other load must be hooked up before you turn the Atma on, otherwise you risk damaging the output transformer. If you want to hook up two cabinets you need to get a splitter box which gets hooked up to one of the three outputs, always just use one, never two or three outputs at the same time. If you have two cabinets with the same impedance hooked up to a splitter box, the single out put with half the impedance value must be used. Example two 16 ohm cabinets connected to a splitter box, the box gets connected to the 8 ohm speaker output only!
Line Out – Back Panel
The line out is a frequency adjusted line level signal from the power-amp. A speaker cabinet or other load needs to be hooked up at all times. Due to space restrictions, a 3.5mm mono connector is used.
- Foot switchable 3 channel all tube amplifier with effects loop
- EL84 class-A cathode biased power amp with EZ81 tube rectifier delivers 18 watts
- Built in power attenuator lets you scale down the power and headroom from 18, 5 to 1 watt. Allows fantastic low volume bedroom amp tone, gain and feel
- Clean channel with volume and tone controls plus a bright switch lets you dial in a variety of sounds from blackface mid-scooped to thick tweed tone
- Overdrive channels share the usual bass, mid, treble controls as well as a 3 position voicing/gain switch covering 60’s, 70’s and 80’s gain and tonal characteristics. A single gain control sets the overall gain for the crunch and solo channel while the crunch preset gain control on the back panel lets you dial in the gain difference between the two overdrives.
- Thin aluminum outer-shell and chassis allows for considerably smaller sizes for traveling light while the baltic-birch speaker baffle board projects classic organic tones
- 16, 8 and 4 ohm speaker outputs allows use with most speaker cabinets. for multiple cabinets a splitter box needs to be used
- Extreme compact and small 3 channel all tube design
- Single instrument input
- 3 position channel selector switch
- Clean: twisted tone, volume and 3 position bright switch
- Crunch & Solo: Common gain, bass, middle, treble controls
- Crunch gain preset control
- 60, 70, 80 gain structure voicing switch
- Buffered series fx loop
- 18W EL84 power amp section
- EZ81 tube rectifier
- Modern Vintage style switch
- Power attenuator switch for 18, 5 and 1 watt operation
- 16, 8 and 4 ohm speaker outputs
- Frequency adjusted line out (sn:064077 or higher)
- Functions on footswitch: crunch/solo preset and clean/overdrive
- Unique all aluminum chassis design