1. Introduction
The Darkglass Microtubes X 900 is a powerful 900-watt bass amplifier head designed for bass players seeking versatile tone shaping and high-fidelity sound. It integrates the acclaimed X Engine distortion circuit with a comprehensive 6-band graphic equalizer, offering extensive control over your bass tone. This manual provides essential information for the proper setup, operation, and maintenance of your Microtubes X 900.
2. Safety Instructions
- Power Supply: Connect the amplifier only to a grounded AC power outlet with the correct voltage as indicated on the unit. Ensure the power cable is securely connected.
- Ventilation: Do not block ventilation openings. Ensure adequate airflow around the amplifier to prevent overheating. Avoid placing the unit on carpets or in enclosed spaces.
- Moisture: Do not expose the amplifier to rain, moisture, or excessive humidity. Keep liquids away from the unit.
- Servicing: Do not attempt to service the unit yourself. Refer all servicing to qualified service personnel. Opening the chassis voids the warranty.
- Handling: Handle the amplifier with care. Avoid dropping or subjecting it to strong impacts.
- Speaker Connection: Always connect a speaker cabinet with the correct impedance (minimum 2.5 Ohms) before powering on the amplifier to prevent damage.
3. Features
The Microtubes X 900 offers a range of features designed to enhance your bass playing experience:
- Powerful 900 watts of Class D power for impressive volume and clarity.
- Integrated X Engine distortion circuit, inspired by Darkglass X-series pedals, for aggressive, mid-heavy drive tones.
- 6-band graphic EQ for precise midrange control and overall tone shaping.
- High-pass and low-pass filters for versatile sound customization within the X Engine.
- Built-in compressor for enhanced punch and clarity on both clean and distorted channels.
- Three IR cabinet simulation slots for realistic direct recording and monitoring.
- MIDI channel switching for seamless integration into digital setups.
- Programmable mute function for silent practice and recording.
- Auxiliary inputs and headphone outputs for flexible connectivity options.
4. Controls and Connections
4.1 Front Panel Controls
The front panel provides access to all primary sound shaping and input controls.
Figure 1: Front Panel Overview
- INPUT: 1/4" instrument input jack.
- PASSIVE/ACTIVE Switch: Selects input sensitivity for passive or active instruments.
- X Button: Engages the X Engine distortion circuit.
- HPF (High-Pass Filter): Controls the cutoff frequency for the high-pass filter in the X Engine.
- LPF (Low-Pass Filter): Controls the cutoff frequency for the low-pass filter in the X Engine.
- DRIVE: Adjusts the amount of distortion in the X Engine.
- MIX: Blends the clean signal with the distorted signal from the X Engine.
- COMP (Compressor): Controls the amount of compression applied to the signal.
- LEVEL: Sets the overall output volume of the amplifier.
- 6-band Graphic EQ: Sliders for precise frequency adjustments at 250 Hz, 500 Hz, 1.5 kHz, and 3 kHz, plus additional bands.
- MUTE Button: Mutes the amplifier output.
- MASTER: Controls the overall master volume of the amplifier.
4.2 Rear Panel Connections
The rear panel provides all necessary connections for speakers, effects, and direct outputs.
Figure 2: Rear Panel Overview
- SPEAKER OUTPUT: Two Speakon combo jacks for connecting speaker cabinets. Minimum load 2.5 Ohms.
- SEND: 1/4" output for connecting to external effects.
- RETURN: 1/4" input for returning signal from external effects.
- AUX IN: 1/8" stereo input for connecting external audio devices (e.g., MP3 player).
- HEADPHONE VOLUME: Controls the volume for the headphone output.
- HEADPHONE OUT: 1/8" stereo output for headphones.
- USB: USB-C port for connecting to a computer for firmware updates and Darkglass Suite software.
- PRE DI: Balanced XLR output for a pre-EQ/pre-distortion signal.
- POST DI: Balanced XLR output for a post-EQ/post-distortion signal, with switchable IR cabinet simulation.
- GND LIFT: Ground lift switch for DI outputs to eliminate hum.
- MIDI: 5-pin DIN MIDI input for external control.
- FOOTSWITCH: 1/4" jack for connecting a compatible Darkglass footswitch.
- POWER INPUT: IEC power connector for the AC power cable.
- POWER SWITCH: Turns the amplifier on or off.
5. Setup
- Placement: Place the amplifier on a stable, level surface, ensuring proper ventilation. Do not cover the vent holes.
- Speaker Connection: Connect your speaker cabinet(s) to the SPEAKER OUTPUT jacks using high-quality Speakon cables. Ensure the total impedance of your cabinets is not below 2.5 Ohms.
- Instrument Connection: Connect your bass guitar to the INPUT jack using a standard 1/4" instrument cable. Select the appropriate PASSIVE or ACTIVE setting.
- Power Connection: Connect the supplied AC power cable to the POWER INPUT on the rear panel and then to a grounded AC outlet.
- Initial Settings: Before powering on, set all EQ sliders to their center position, and turn the MASTER volume knob fully counter-clockwise.
- Power On: Flip the POWER SWITCH to the 'ON' position. The amplifier will perform a brief startup sequence.
6. Operating Instructions
6.1 Basic Operation
- After setup, slowly increase the MASTER volume to a desired listening level.
- Adjust the LEVEL knob to control the overall output volume.
- Use the 6-band Graphic EQ sliders to fine-tune your tone. Each slider boosts or cuts the specified frequency band.
6.2 Using the X Engine Distortion
- Press the X button to engage the distortion circuit.
- Adjust the DRIVE knob to control the amount of distortion.
- Use the HPF and LPF knobs to set the frequency range for the distortion. The HPF determines where the distortion starts in the low end, and the LPF determines where it ends in the high end.
- The MIX knob allows you to blend the clean signal with the distorted signal, providing clarity and punch even with heavy distortion.
6.3 Compressor
The built-in compressor can be engaged and adjusted using the COMP knob. Turning the knob clockwise increases the compression, adding sustain and evening out dynamics. This can be used on both clean and distorted tones.
6.4 IR Cabinet Simulation
The Microtubes X 900 includes three slots for Impulse Response (IR) cabinet simulations. These can be managed and loaded via the USB connection using the Darkglass Suite software.
Figure 3: Darkglass Suite Software for IR Management
The selected IR is applied to the POST DI output, providing a realistic cabinet sound for direct recording or FOH (Front of House) mixing.
6.5 MIDI Control
The MIDI input allows for external control of various amplifier functions, such as channel switching and preset recall. Refer to the Darkglass website for detailed MIDI implementation charts and compatible footswitches.
7. Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the amplifier. Avoid abrasive cleaners or solvents.
- Ventilation: Regularly check that the ventilation openings are clear of dust and debris. Use compressed air if necessary to clear vents.
- Storage: When not in use for extended periods, store the amplifier in a dry, temperature-controlled environment.
- Cable Inspection: Periodically inspect all cables (power, instrument, speaker) for signs of wear or damage. Replace damaged cables immediately.
8. Troubleshooting
- No Power: Ensure the power cable is securely connected to both the amplifier and a working AC outlet. Check the power switch position.
- No Sound:
- Verify that a speaker cabinet is connected and the speaker cable is functional.
- Check the instrument cable and ensure your instrument is working.
- Ensure the MUTE button is not engaged.
- Check MASTER and LEVEL knob settings.
- Distorted Sound (unexpected):
- Check the X button status; if engaged, adjust DRIVE and MIX.
- Ensure the input gain (PASSIVE/ACTIVE switch) is appropriate for your instrument.
- Lower the LEVEL or MASTER volume.
- Hum or Noise:
- Ensure all cables are properly shielded and connected.
- Try engaging the GND LIFT switch on the rear panel for DI outputs.
- Check for ground loops in your setup.
If problems persist after checking these points, contact Darkglass Electronics support or an authorized service center.
9. Specifications
| Specification | Value |
|---|---|
| Power Output | 900 Watts (Class D) |
| Product Dimensions | 15 x 5 x 12 inches (38.1 x 12.7 x 30.5 cm) |
| Item Weight | 8.42 pounds (3.82 kg) |
| Minimum Load Impedance | 2.5 Ohms |
| EQ Bands | 6-band Graphic EQ (250 Hz, 500 Hz, 1.5 kHz, 3 kHz, etc.) |
| Distortion Circuit | X Engine |
| Connectivity | USB-C, MIDI, Aux In, Headphone Out, XLR DI (Pre/Post) |
10. Warranty and Support
Darkglass Electronics products are manufactured to the highest quality standards. For information regarding warranty coverage and terms, please refer to the warranty card included with your product or visit the official Darkglass Electronics website. For technical support, troubleshooting assistance, or service inquiries, please contact Darkglass Electronics customer support through their official channels.
Darkglass Electronics Website: www.darkglass.com
