Darkglass Electronics microtubes 900 User manual

The Microtubes 900™ is a 900W amplifier equipped
with an all analog preamplifierand a Class D Power
Module. The first thing you will notice from the
Microtubes 900 is its unusual control layout:
On the right side you’ll find the clean section which
is the foundation of your tone.
It features Gain and Master controls an active 4
band EQ. Along with Low and Treble controls you
will find Low Mids and Hi Mids control, each knob
with their own 3-way frequency switch.
On the left side you will find the Microtubes® Engine
which acts as an extra channel that can bring your
clean tone to the next level by helping you cut
through the mix while adding anything from subtle
tube break up, harmonics and natural compression
to obliterating distortion.
DESCRIPTION
The Microtubes Engine™ can be engaged via the
front panel or our own digitally controlled
Intelligent Footswitch™ (jack on rear panel). Besides
engaging the Microtubes circuitry you can hold the
actuator to Mute the amplifier.
We equipped the power module with some unique
control over the power output and minimum speaker
loads:
The standard mode will deliver 900W RMS at 4
Ω/500W at 8Ω. If you select the 2ΩMode via the
rear panel switch the amplifier will deliver 900W at
2Ω/500W at 4Ωand 350W at 8Ω.
This feature allows for maximum power adaptability.
It doesn’t matter the cabinet configuration or power
requirements, the Microtubes 900 will deliver
accordingly.

INPUT : Connect your instrument via a standard ¼”
mono cable.
PASSIVE/ACTIVE : Switch from passive to active
mode. Some active basses can have a hotter signal
output which can make the amp distort early (feel
free to use it on Passive move even with active
basses if such additional distortion is desired).
MICROTUBES: Turns on or off the Microtubes Engine
™ to add natural compression, organic harmonic
enhancement, and saturation ranging from mild
overdrive to high gain bass rage.
The Microtubes Engine operates before the clean
section (you can therefore use the 4 Band Active EQ
for additional tone shaping in addition to the Tone
knob described below).
DRIVE : Controls the amount of distortion that the
Microtubes Engine will deliver. It will change
from a soft warm overdrive to a massive modern
distorted tone.
FEATURES
FRONT PANEL
TONE : Controls the high harmonic content of the
Microtubes Engine via a variable low pass filter:
crank it up for additional attack and definition or
dim it down for a smoother sound. This is handy if
running bright clean EQ settings or cabinets with
tweeters.
LEVEL : Controls the Microtubes Engine’s output
volume.
BLEND : Mixes between the Clean signal and the
Distortion signal (Microtubes Engine).
B3K/VMT : Selects between two overdrive voicings:
B3K mode will deliver an aggressive, percussive
sound while the VMT will bring up the mids for a
warmer, more neutral character.

GAIN : Changes the volume of the signal the Active
4 Band EQ. You can set it low prior to ensuring the
cleanest operation possible or set it higher for more
aggressive growl.
BASS : +-12dB at 80Hz. Changes the low content of
the signal.
LOW MIDS : +-12dB of the selected frequency via the
LOW MIDS ƒ switch (described below). Changes the
lower mid content of the signal.
LOW MIDS ƒ : Use this switch to change the
frequency of the low mid band from 250Hz, 500Hz
or 1kHZ.
HI MIDS : +-12dB of the selected frequency via the
HI MIDS ƒ switch (described below). Changes the
higher mid content of the signal.
HI MIDS ƒ : Use this switch to change the frequency
of the hi mid band from 750Hz, 1.5kHz and 3kHZ.
TREBLE : +-12dB at 5kHz. Changes the high content
of the signal.
MASTER : Controls the overall volume of the
amplifier.
MUTE : Mutes the amplifier.

FEATURES
BACK PANEL
SPEAKER OUTPUT : Connects the amplifier to your
cabinet. This Speakon combo jack allows for either
Speakon or ¼” speaker cable operation.
WARNING: Do not use an instrument cable with this
jack. Using an instrument cable can damage your
amplifier.
MIN - LOAD : Press when using a 2Ωload. You can
use this control to lower the output if your 4Ω
cabinet is not able to handle more than 500W (you
can also get 350W with an 8Ωcabinet in this
configuration).
PRE AMP OUT : This output connects the preamp to
a different power amp.
POWER AMP IN : Use this input to connect a
different preamp to the power amp. (master volume
will be disabled)
POST - PRE : Selects what signal will be delivered
by the DI output. Selecting PRE, sends a clean copy
of your input bass signal. Selecting POST delivers a
signal processed by the preamp of the amp (gain,
distortion, eq, master, etc.)
GROUND LIFT : Lifts the ground of the DI XLR
output. If a ground noise in you DI signal is
experienced, try changing the setting of this control.
BALANCED OUTPUT: Connects the Microtubes 900
preamplifier to balanced equipment (mic preamp,
console, recorder, compressor, audio interface, etc.)
via a standard XLR jack.
FOOTSWITCH : The Footswitch allows you to remotely
engage and disengage the Microtubes Engine. Hold
the footswitch to Mute the amplifier. The VMT/B3K
push button will remain operational with the
Intelligent Footswitch plugged in.

FAN : The fan forces air inside out the amp to help
the heatsink system to cool the amp. Be sure to
never cover the vent holes.
AC SOCKET : Connects the power cord to the
amplifier.
AC POWER ON/OFF : Turns the amplifier on or off.
Use a regular mono instrument cable to connect the
amplifier to the footswitch.
Remove the cable from the footswitch jack in the
rear panel if you want to control the amp from the
front panel.
The Microtubes 900 will only work with our
proprietary Intelligent Footswitch (included with the
amplifier). A generic Footswitch will not work with
the Microtubes 900.

BLOCK DIAGRAM
DRIVE
VMT
TONE
CLEAN
LEVEL
BLEND
INPUT
PASSIVE /
ACTIVE
MICROTUBES /
CLEAN
MICROTUBES ENGINE
VMT /
B3K
BASSTREBLE
B3K
LO MI D FREQHI MID
MASTER
POWER
MUTE
POST
2Ω
PRE
PRE
OUT
POWER
IN
SPEAKER
OUTPUT
DI OUTPUT
GAIN
FREQ

WARNING
- Do not open the amp. No user serviceable parts inside the
amplifier.
- Make sure the voltage selector switch on the left
side panel is set properly (115V/230V) before plugging the ampli-
fier on the AC outlet.
- Never use the amp at a high moisture environment or near
liquids.
- The Microtubes 900 can deliver more than 115 db of power.
Exposure to this level of sound can damage your hearing. Use
proper hearing protection if you will be exposed.
- The Microtubes 900 can deliver more than 900 Watts. Be sure
that your speaker cabinet is able to handle that power. You can
reduce the output of the amp by selecting the 2Ωmode on the
rear panel (by the Speakon output jack).
- Do not cover the vent holes. The Fan and vent holes are part
of the cooling system of the amp. Covering the vent holes can
produce overheating of the power amp damaging it.
- Do not use an instrument cable as speaker cable. An Instru-
ment cables are not design to deliver power signals going from
the amplifier to the speaker.
For more information, frequently asked questions (FAQ) and
troubleshooting, please visit: http://www.darkglass.com/micro-
tubes900-faq
EMC / EMI
This equipment has been tested and found to comply with the
limits for a Class B Digital device, pursuant to part 15 of the FCC
rules. These limits are designed to provide reasonable protec-
tion against harmful interference in residential installations.
This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communi-
cations. There is no guarantee that interference will not occur in
a particular installation.
If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct
the interference by one or more of the following measures:
· Reorient or relocate the receiving antenna.
· Increase the separation between the equipment and receiver.
· Connect the equipment to an outlet on a circuit different from
that to which the receiver is connected.
· Consult the dealer or an experienced radio/TV technician for
help.

WARRANTY AND SPECS
WARRANTY
Please register for your warranty at
http://mypedal.darkglass.com. The Microtubes 900 is
under warranty to the original owner for a period
of three years against manufacturing defects.
If you experience a problem with the unit, please
contact [email protected] to receive a Return
Authorization number or for information on the
nearest authorized repair center. A copy of your
original receipt must be included with all warranty
repairs. You are responsible for all shipping
charges. The unit must be shipped to us freight
prepaid. We will return the unit freight collect.
Darkglass Electronics Oy is not responsible for
shipping damage either to or from our service
center. Claims must be filed with the carrier.
Repairs outside the EU please contact your local
dealer or distributor for your country’s specific
warranty period and repair procedures. Darkglass,
Microtubes and Microtubes Engine are registered
trademarks of Darkglass Electronics Oy,
Hernesaarenranta 3L, 00150 Helsinki, Finland.
SPECIFICATIONS
Input Impedance: 1MΩ
Minimum Load Impedance: 4Ω(2Ωin 2Ωmode)
Maximum Power Output: 900 Watts RMS @ 4Ω(1khz
full blast 2 min max) 20%THD (450 Watts RMS @ 8Ω)
Power Amp Input Impedance: 1MΩ
Power Amp Input Level: 1500 mV RMS 1200MV RMS
at 2 ohm mode
Pre-Amp Output Impedance: 1kΩ
Pre-Amp Output Level: 1200 mV
Maximum Power Consumption: approx. 700VA
Forced-air cooled
AC Input Power: 100-250 VAC (Via selector switch
on left side panel).
Cycles: 50/60 Hz
Dimensions: 26.7cm l x 7cm h 25.5 w (10.5”l x 2.75”h
x 10”w)
Weight: 2.9Kg (6.39Lbs)
Built and Engineered in Helsinki, Finland.

For more information, frequently asked questions (FAQ) and
troubleshooting, please visit: http://www.darkglass.com/micro-
tubes900-faq
EMC / EMI
This equipment has been tested and found to comply with the
limits for a Class B Digital device, pursuant to part 15 of the FCC
rules. These limits are designed to provide reasonable protec-
tion against harmful interference in residential installations.
This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communi-
cations. There is no guarantee that interference will not occur in
a particular installation.
If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct
the interference by one or more of the following measures:
· Reorient or relocate the receiving antenna.
· Increase the separation between the equipment and receiver.
· Connect the equipment to an outlet on a circuit different from
that to which the receiver is connected.
· Consult the dealer or an experienced radio/TV technician for
help.

DARKGLASS ELECTRONICS®
HERNESAARENRANTA 3L 00150
HELSINKI, FINLAND
WWW.DARKGLASS.COM
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