electro-harmonix Op Amp Big Muff Pi User Manual
- June 6, 2024
- electro-harmonix
Table of Contents
Op-Amp Big Muff Pi
Congratulations on your purchase of the Op-Amp Big Muff, our faithful re- creation of the late `70s circuit. The circuitry of the Op-Amp Big Muff sometimes also referred to as the IC or V4 Big Muff differs from the traditional transistor-based Big Muff circuit in that it uses operational amplifiers (op-amps) to achieve its signature sustaining distortion sound. With widely-sweeping tone controls and a character all its own, the Op-Amp Big Muff will surely be a formidable addition to your sonic arsenal.
OPERATING INSTRUCTIONS
VOLUME – Control Sets the output level
TONE Control – Provides a range of sounds from high treble to deep bass.
As you turn the knob clockwise the treble increases and bass decreases.
TONE Switch – Removes the TONE control from the circuit. This switch
has been improved over the original Op-Amp Big Muff in that the volume remains
the same in both positions.
FUZZ Control – Adjusts the amount of sustain and distortion Footswitch &
Status LED When the LED is lit, the Big Muff effect is active. When the LED
is off, the Big Muff is in true bypass mode. The Footswitch toggles between
effect and bypass modes.
INPUT Jack – This ¼” jack is the audio input to the Op-Amp Big Muff. The
input impedance presented at this jack is 55 k.
AMP Jack – This ¼” jack is the audio output from the Op-Amp Big Muff.
When the Big Muff is in bypass mode, the AMP jack is connected directly to the
INPUT jack.
9V Power Jack – The Op-Amp Big Muff is powered from a 9V battery or you can use an optional 9VDC AC Adapter capable of delivering at least 25mA to the 9V power jack, such as the EHX9.6DC-200. The AC Adapter must have a center- negative plug. The battery may be left in or taken out when using an AC Adapter. The Op-Amp Big Muff has a current draw of approximately 5mA at 9VDC.
We recommend the Electro-Harmonix US96DC-200BI AC Adapter to power your Op- Amp Big Muff.
CHANGING THE BATTERY
To change the 9-volt battery, you must remove the 4 screws on the bottom of the Op-Amp Big Muff. Once the screws are removed, you can take off the bottom plate and change the battery. Please do not touch the circuit board while the bottom plate is off or you risk damaging a component.
WARRANTY INFORMATION
Please register online at http://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, RA#, and a copy of your receipt clearly showing the purchase date.
United States & Canada
EHX CUSTOMER SERVICE
ELECTRO-HARMONIX
c/o NEW SENSOR CORP.
47-50 33RD STREET
LONG ISLAND CITY, NY 11101
Tel: 718-937-8300
Email: info@ehx.com
Europe
JOHN WILLIAMS
ELECTRO-HARMONIX UK
13 CWMDONKIN TERRACE SWANSEA SA2 0RQ
UNITED KINGDOM
Tel: +44 179 247 3258
Email:
electroharmonixuk@virginmedia.com
References
Read User Manual Online (PDF format)
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