LPB-2ube Instructions

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Congratulations on your purchase of the LPB-2ube! The LPB-2ube is a full bandwidth (20-20K), stereo pre-amp with an all-tube signal path using two premium 12AX7WB vacuum tubes.  Carefully reading these instructions will ensure you will get the most out of your LPB 2ube.

Included with the LPB-2ube is a unique 12VAC/1000mA adapter.  Use only the adapter supplied.  Using any other adapter can cause harm to you, the LPB-2ube and the adapter.  DO NOT LEAVE THE ADAPTER PLUGGED INTO A POWER OUTLET IF IT IS NOT PLUGGED INTO THE LPB-2UBE.


INPUT LEVEL Switch -Selects between LO and HI input level. The LO setting will provide more overall gain through the LPB-2ube, the HI setting provides less gain.  If the input signal is from a low-level source such as a guitar or an instrument that uses pickups, then the LPB-2ube will work best in the LO setting.  If the input signal is from a line level source such as a synthesizer, sampler, or mixer, the LPB-2ube will work best in the HI-setting. This switch controls both the left and the right channels simultaneously.

DRIVE R & DRIVE L Knobs - Adjusts the amount of gain or drive for each channel.  Drive R controls the right channel and DRIVE L adjusts the left channel.

VOLUME R & VOLUME L Knobs - Adjusts the overall output level or volume for each channel.  VOLUME R controls the right channel and VOLUME L adjusts the left channel.


POWER LED - Lights when the LPB-2ube is powered on.
STATUS LED - Lights when the LPB-2ube effect is engaged; Stays off when the LPB-2ube is in true bypass mode.

- I/O Routing -

Mono-to-Stereo Signal Splitter - The LPB 2ube can be configured as a signal splitter.  Plug an instrument into the R (mono) Input and leave the Left Input unplugged.  This will allow the signal going through the Right Input to go into both the right and left amplifier channels.  Each amplifier section is processed independently, whether it is two guitar amps, a series of Electro-Harmonix effects pedals, tape recorder inputs, or two mixer channels.

Stereo-to-Stereo - To use the LPB-2ube as a stereo pre-amp, plug the left and right outputs on your instrument into the Left and Right Inputs of the pedal respectively.  Each stereo channel is independently controlled.  Connect the outputs to the inputs of your tape recorder, mixer or power amp.

Mono - The LPB-2ube can be configured as a mono tube distortion pedal by putting the two pre-amp channels in series.  This provides 2 volumes and 2 drive controls, which can be set for a wide variety of overdrives. Experiment with the four knobs and you will see the many possibilities… from bluesy to total grunge and anywhere in between.  An additional patch cable will be needed, preferably one that is 1 ft. in length or shorter.  Plug your instrument into the R (mono) Input.  Plug one end of the short cable into the Left Input and the other end into the Right Output. The output of the LPB-2ube will come from the Left Output, so plug the Left Output into the guitar amp. Warning: This setup can be very loud; make sure the amp is off when setting it up and the VOLUME L knob is turned down all the way before turning the amp on.

Hard Disk Recording - Virtually all of today’s audio converters, in the home studio market, which are related to hard disk recording not only need pre-amplification but demand pre-amplification in order to get a clean high gain signal for optimum recording.  The LPB-2ube presents an all tube, analog circuitry to give a fat signal with a warmth and calority that will not be lost when the signal enters the digital domain.  The LPB-2ube is your first step in the audio chain.  It guarantees that what is put on disk is the highest quality sound with the character and tightness that is just unattainable from direct insertion.

WARNING: There are extremely high voltages in the LPB-2ube even when it is unplugged - DO NOT OPEN THE LPB-2UBE.


Please register online at https://www.ehx.com/product-registration or complete and return the enclosed warranty card within 10 days of purchase. Electro-Harmonix will repair or replace, at its discretion, a product that fails to operate due to defects in materials or workmanship for a period of one year from date of purchase. This applies only to original purchasers who have bought their product from an authorized Electro-Harmonix retailer. Repaired or replaced units will then be warranted for the unexpired portion of the original warranty term.

If you should need to return your unit for service within the warranty period, please contact the appropriate office listed below. Customers outside the regions listed below, please contact EHX Customer Service for information on warranty repairs at info@ehx.com or +1-718-937-8300. USA and Canadian customers: please obtain a Return Authorization Number (RA#) from EHX Customer Service before returning your product. Include with your returned unit:  a written description of the problem as well as your name, address, telephone number, e-mail address, and RA#; and a copy of your receipt clearly showing the purchase date.

United States & Canada
55-01 2ND STREET
Tel: 718-937-8300
Email: info@ehx.com

Tel: +44 179 247 3258
Email: electroharmonixuk@virginmedia.com

This warranty gives a purchaser specific legal rights.  A purchaser may have even greater rights depending upon the laws of the jurisdiction within which the product was purchased.

To hear demos on all EHX pedals visit us on the web at www.ehx.com
Email us at info@ehx.com


Note: 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 protection against harmful interference in a residential installation. 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 communications. However, 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 into 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.

Modifications not expressly approved by the manufacturer could void the user’s authority to operate the equipment under FCC rules.

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