Atma-Sphere Music Systems St. Paul, MN 55105 Phone: 651-690-2246 FAX: 651-699-1175 http://www.atma-sphere.
CONGRATULATIONS! You have purchased one of the world's finest preamplifiers and certainly one of the most unique. It was over fifteen years in development and represents a level of performance that others will be struggling to achieve for years to come. At the time of this writing, it is the only fully balanced differential vacuum-tube design in the world the also supports the 600 ohm standard.
LIMITED WARRANTY ON ATMA-SPHERE® MUSIC SYSTEMS PRODUCTS This warranty on your ATMA-SPHERE® MUSIC SYSTEMS product, which is distributed and warranted by ATMA-SPHERE® MUSIC SYSTEMS, shall remain in effect for two (2) years from the date of consumer purchase, provided the enclosed registration form is completed and returned to ATMASPHERE® MUSIC SYSTEMS within ten days of purchase. WHAT IS COVERED: Except as specified below, this warranty covers all defects in materials and workmanship.
MUSIC PREAMPLIFIER SET-UP AND OPERATION Unpack the preamplifier and its power supply carefully and save the packaging containers for future shipment if required. Warranty may be void if the unit is shipped in a different container. If you do not have a container, contact ATMA-SPHERE® MUSIC SYSTEMS for a replacement. The replacement container is $30.00. Place the tubes in the appropriate sockets as shown in the tube chart elsewhere in this manual. There is no tube in the power supply.
Almost all phonograph cartridges are balanced sources. Thus the MP-1 allows you to set up your turntable as a fully-balanced source, with considerable sonic advantage. For best results, follow the connection scheme outlined below: 1) Use a cable that has two signal conductors PLUS a shield for each channel. The two conductors are for the plus and minus outputs of the cartridge, and the shield connection becomes the tone arm/turntable ground connection and is common to BOTH channels.
MP-1 tube locations 8/98
NOTES ON TUBES 1) The 12AT7s in the upper left of each board are the most critical for low noise phono operation. 2) The constant current sources are outside of the signal path. 3) Matched sections in the frontmost 6SN7 of the preamp will reduce noise during operation of the front panel GAIN TRIM control. 4) Tube damping rings are recommended. 5) Do not remove tubes while unit is operating.
TROUBLESHOOTING TIPS Front panel LEDs on the power supply don't light up: Check the rear panel fuse and verify that the power cord is plugged in. Buzz, hum and/or RF interference: Make sure that the power cord is plugged into a properly grounded outlet and that no other equipment in the system is grounded (resulting in a ground loop). Sometimes RF can get into the phonograph through poorly shielded wiring in or from the tone arm. This is more common with straight-tracking arms.
NOTES
WARRANTY REGISTRATION FORM IMPORTANT: This form must be filled out and returned to ATMA-SPHERE® MUSIC SYSTEMS within 10 days of purchase to validate the warranty! Please type or print clearly.
