Electro-Harmonix Op-Amp Big Muff Pi Operating Instructions page 2

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.
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
CHANGING THE BATTERY
WARRANTY INFORMATION
Europe
JOHN WILLIAMS
ELECTRO-HARMONIX UK
13 CWMDONKIN TERRACE
SWANSEA SA2 0RQ
UNITED KINGDOM
Tel: +44 179 247 3258
Email: electroharmonixuk@virginmedia.com