Carvin BX Micro Bass Amplifiers

Speaker Configurations

MB10: 2-Way Enclosure, 10" Woofer, 1" Neo Titanium Tweeter. Dimensions: 12.75"W x 11.5"D x 18.5"H (324mm x 292mm x 470mm).

MB15: 2-Way Enclosure, 15" Woofer, 1" Neo Titanium Tweeter. Dimensions: 17"W x 12"D x 18.5"H (432mm x 305mm x 470mm).

MB12: 3-Way Enclosure, 12" Neo Horn Loaded Woofer, 6.5" Neo Mid Driver, 1" Neo Titanium Tweeter. Dimensions: 17"W x 12"D x 18.5"H (432mm x 305mm x 470mm).

Helpful Hints

• No Sound: MUTE function engaged or speakers improperly connected.
• No High Frequencies: TWEETER DIM or HIGH FREQUENCY ATTENUATION control is low/OFF, or HF driver is damaged.
• Amp Sensitive to Input: DRIVE control is too high, or ACTIVE switch needs adjustment.
• XLR Hum: Try the GND LIFT switch; check external effects or cabling.
• Poor Bass from Multiple Enclosures: Ensure correct speaker phase (+/-) wiring.
• Maximum Output: Use multiple speakers/enclosures (doubling speakers quadruples acoustic output). Load to lowest minimum impedance for maximum RMS power. Exceeding minimum load triggers "protect" mode.

Ensure speakers are suitable for wattage. Reduce volume if distorted sound occurs.

Important Safety Information

Risk of Electric Shock: ⚠️ Do not open. Contains dangerous voltage.

Important: Refer to accompanying literature for operating and maintenance instructions.

General Precautions:

• Keep away from water and moisture.
• Connect only to specified power sources.
• Do not defeat grounding or polarization.
• Protect power cords from being walked on or pinched.
• Servicing should only be performed by qualified personnel.
• Replace fuses only with the same type.

Safety Instructions (European): AC power cord colors: GREEN & YELLOW - Earth, BLUE - Neutral, BROWN - Live.

U.K. Main Plug Warning: Never use a cut-off molded plug.

Caution: Risk of Electric Shock. Refer servicing to qualified personnel. Unit contains high voltage inside.

Limited Warranty

Carvin products are guaranteed against failure for 1 year from the date of purchase. Carvin will service and supply parts at no charge within the warranty period, provided the unit is under warranty. Shipping costs are the customer's responsibility. Carvin is not liable for parts or servicing from other sources. An original invoice copy is required for warranty verification. Carvin is not responsible for horn drivers or speakers damaged by the unit. This warranty does not cover damage from natural disasters, accidents, abuse, loss of parts, lack of reasonable care, incorrect use, or failure to follow instructions. This warranty is in lieu of all other warranties. No representative is authorized to assume liability for Carvin. Carvin shall not be liable for incidental or consequential damages.

Maintaining Your Equipment

Avoid spilling liquids or foreign matter inside the unit. Clean the panel with a dry or slightly damp cloth. Avoid prolonged use in caustic environments (salt air); protect the amplifier if used in such conditions.

Service

USA: Visit www.carvinservice.com.

Outside USA: Contact your dealer or visit http://www.carvinworld.com for the nearest service center. Include a written description of the problem, serial number, and date of purchase.

Product Overview

The BX Series Bass Amplifiers offer classic natural bass tone with unprecedented tonal control and extended headroom. The BX250 Microbass amps deliver 200W at 8 ohms and 250W at 4 ohms, fitting into a small space. Four discrete Class A input stages provide the harmonic basis for the preamp. The amplifier features a flat response with extensive tone controls for signature sound shaping. The DRIVE control increases harmonic content. The CLASS-D output and lightweight switch-mode power supply are energy efficient and produce less heat. The BX Microbass is designed for light weight, solid design, and durable construction.

Key Features

• Discrete CLASS A input stages
• Preamp DRIVE and MASTER volume controls
• 2 mid-sweep semi-parametric EQ, BASS and TREBLE
• CONTOUR pre-shape control
• Single-knob COMPRESSOR
• DIRECT OUT balanced XLR with LEVEL, PRE/POST and GROUND/LIFT
• MUTE switch for silent tuning or headphone practice
• TUNER/PHONES output jack (independent of MUTE)
• TWEETER DIM switch (for combos)
• CLASS-D amplifier for cool operation and low power consumption
• Solid metal shaft controls with threaded metal bushings
• MIL SPEC, double-sided, FR-4 glass epoxy circuit boards
• Energy-efficient worldwide power supply (90-250VAC, 50-60Hz)
• Compact and lightweight design
• Designed and manufactured by Carvin in the USA

Getting Started

1. With POWER off, connect your instrument to the INPUT jack. For the BX250 head, connect a speaker (4 ohms or higher) to a speaker out jack.
2. Set DRIVE and MASTER volume to "0". Set the ACTIVE INPUT switch for your bass type.
3. Set tone controls to center "0" and CONTOUR to FLAT for a neutral setting.
4. Turn the amp ON. Turn up your bass volume. Gradually increase the MASTER control. If no sound, check MUTE switch, speaker connections, and POWER/PROTECT LED.
5. Increasing the DRIVE control adds harmonic richness and volume. Re-adjust MASTER after changing DRIVE.
6. Adjust tone controls as desired. Sometimes cutting a MID control yields better results than boosting others.
7. For more volume, use multiple speakers. Doubling speakers increases acoustic output by four times. Be aware of speaker wattage limits to prevent distortion or damage.

Explore the features to realize the full potential of your BX Microbass.

Receiving Inspection

Inspect your unit for shipping damage and notify the shipping company and CARVIN immediately if found.

Save the carton and all packing materials for potential future shipping. CARVIN and the shipping company are not liable for damage caused by improper packing.

Save your invoice; it's required for warranty service.

If items are missing, they may have shipped separately; allow several days for arrival before inquiring.

Record the serial number for your records and return your portion of the warranty card.

Registration: USA customers: www.carvin.com/registration. All other countries: www.carvinworld.com/registration.

Specifications

Front Panel Controls

1. INPUT JACK: 1/4" phone jack for instrument input (high impedance, active/passive basses).

2. JEWEL LIGHT: BLUE = POWER ON/SYSTEM NORMAL; RED = STARTUP/MUTE/COMP/PROTECT. Solid RED indicates MUTE or PROTECT mode. Flashing RED indicates COMPRESSOR active. If power indicator turns OFF or solid RED (not muted), reset the amp by turning it OFF for 10 seconds, checking speaker connections, then turning it back ON.

3. MUTE SWITCH: Turns off signal to amplifier and DIRECT OUT. JEWEL LIGHT turns RED. Useful for changing basses, silent tuning, or headphone practice. TUNER/PHONES output is unaffected.

4. ACTIVE SWITCH: UP position for basses with active preamps; DOWN for standard pickups.

5. DI LEVEL (DIRECT OUT, PHONES): Controls output level for XLR DIRECT OUT and 1/4" PHONES/TUNER jack. Not affected by MASTER level. Use PRE/POST switch to determine if DRIVE, COMPRESSOR, and TONE controls affect this signal.

6. DRIVE CONTROL: Adjusts input level to Class A preamps. Affects input sensitivity and harmonic content (higher settings produce more overdrive). Also affects volume; use with MASTER for desired level.

7. CONTOUR CONTROL: Variable mid-range scoop. FLAT setting = no change. Clockwise rotation scoops mids, centered at 350Hz, up to -15dB at 500Hz at maximum.

8. BASS AND TREBLE TONE CONTROLS: Custom-shaped controls for lows and highs. Boosts when turned right, cuts when turned left. BASS affects frequencies starting at 80Hz; TREBLE affects frequencies starting at 5kHz.

9. SEMI-PARAMETRIC MID SWEEP TONE CONTROLS (LO MID, HI MID & FREQ): FREQ control adjusts the center frequency for the LO MID and HI MID GAIN controls. GAIN controls boost or cut mids. Experiment with FREQ and GAIN to fine-tune overall sound.

10. COMPRESSOR: Reduces volume of incoming signal peaks. Clockwise rotation increases compression ratio (1:1 at OFF, 3:1 at MAX). Helps reduce transients for smoother playing and allows higher overall volume without distortion. JEWEL LIGHT flashes RED for loud peaks when compressor is active.

11. MASTER VOLUME: Controls overall amplifier volume. Reduce if sound becomes distorted. Compressor can help prevent distortion.

Rear Panel Controls

12. DIRECT OUTPUT XLR JACK (MUTED): Balanced output for PA or recording. Level controlled by DI LEVEL. Muted by MUTE switch. Signal not affected by MASTER. PRE/POST switch determines if DRIVE, TONE, COMPRESSOR affect the signal. Protected against phantom power.

13. DIRECT OUTPUT GROUND LIFT SWITCH: Use to eliminate hum when connecting XLR to a mixer. Lifts pin 1 of XLR 100 ohms above chassis ground.

14. PRE/POST SWITCH: Affects DIRECT OUT and PHONES/TUNER signal. POST: DRIVE, COMPRESSOR, TONE controls affect signal. PRE: Bypasses these controls.

15. PHONES/TUNER JACK (UNMUTED): Stereo 1/4" jack for tuner or headphones. Volume controlled by DI LEVEL. Unaffected by MUTE switch. PRE/POST switch affects this output.

16. TWEETER DIM SWITCH (MB COMBOS): Attenuates the internal tweeter to control speaker brightness. Does not affect external speakers.

17. SPEAKER OUTPUTS:

• MB10, MB12, MB15: One 1/4" extension speaker output (parallel with internal 8 ohm speakers). Connect another speaker with impedance > 8 ohms.
• BX250 Head: Two 1/4" speaker outputs. Total impedance must not go below 4 ohms. Exceeding minimum load triggers PROTECT mode.

Speaker Combination Examples:

• One 16 ohm + one 8 ohm (MB spkr.) = 5.33 ohms (OK)
• One 8 ohm + one 8 ohm (MB spkr.) = 4 ohms (OK)
• One 4 ohm + one 8 ohm (MB spkr.) = 2.66 ohms (NO)
• Two 8 ohm speakers = 4 ohms (OK for BX250 head)

18. POWER SWITCH: Turns the amplifier ON or OFF. JEWEL LIGHT is RED for 2-4 seconds during startup.

19. AC POWER JACK & FUSE: Accepts 90-250VAC, 50/60Hz. Use a grounded 3-prong power source. Internal fuse: 250V Slow Blow, 5A.