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1742 Selby Av.
St. Paul, MN 55104
6516902246
atmasphere.com
MA1 Mk.III amplifier setup and operation instructions
Installation: Place the amps in your system. Connect the preamp cable to the appropriate input connector on the rear of
the amp. If you use the RCA input connection, make sure a shorting jumper is installed between pins 1 & 3 on the XLR
connector else a buzz is possible. Verify that both power switches are OFF (down). Connect AC power to the AC input
connector on the rear of the amp. Connect the negative speaker cable to the negative output terminal and the positive
speaker cable to the positive output terminal. The amplifier is noninverting from the RCA input or pin 2 of the XLR.
Setup: Install the tubes in their sockets. The middle group of five sockets (no cooling holes) take the 6SN7GT driver
tube. All others are the 6AS7G output tubes. A total compliment of five driver and fourteen output tubes are required per
each chassis. Engage the Main Power switch (amber lamp, left side of chassis) and verify that the amber indicator
lights. In about 15 seconds, the filaments of all tubes should be visibly glowing orange. After at least one minute, engage
the Standby switch (red lamp, right side of chassis). The amplifier is now fully powered up.
DC Offset adjustment/Meter Switch: The middle switch controls the meter. Up is full power for full scale into 8 ohms,
Down is 1 watt for full scale. In the Down position, if the meter has a reading with no input signal, adjust the control for
no reading. This will be a null or dip in the meter setting. During normal operation, the Low position may only be useful
for high efficiency speakers. Use the High position if the meter is pegged to the right In the Low position.
Operation: The amplifier is now completely operational. Standby can be used at any time without loss of the warmup
character of the amplifier.
The MA1 will handle a four ohm speaker rather well. But, as for any tube amplifier, a speaker of 8 ohms is
recommended. Speakers of less then 8 ohms or speakers that are four ohms or less in the bass will not demonstrate all
the capabilities of any tube amplifier. If you must use a four ohm speaker, be careful to keep the length of the speaker
cables as short as possible, and in any event the speaker connections should be as tight as possible. Note that with a
tool to tighten the speaker connections on the rear of the amplifier care should be taken not to damage the connectors
by overtightening. Speakers of 4 ohms or less can also be used by use of the ZERO product; see
http://www.zeroimpedance.com for details.
New tubes may exhibit arcovers directly after shipment. If a tube arcs, put the amp in Standby, let it sit for a minute,
then tap the tube gently and try the amp again. Often the arcing will clear. If not, replace the tube. Sudden changes in
the meter null setting may indicate a damaged tube. If you are unable to adjust the DC Offset this may also be an
indication of a bad tube or tubes. If the meter pegs a short is in one of the tubes. Do not allow this condition to
persist! The meter will settle out when the offending tube is removed and replaced.
Fuses: The fuse by the power cord entry is the Output section B+ and is 5 Amp Slow (2.5A slow for
235V). Check this fuse if the amp lights up but does not play. The middle fuse is the filament fuse and is 5 Amp Slow
(2.5A for 235). The last fuse controls the driver circuit and is .5 Amp slow (.25A Slow for 235 Volt). WARNING! To avoid
fire hazard, always replace fuses with same type and rating.
2007 AtmaSphere Music Systems Inc. 1742 Selby St. Paul, MN. 55104 651.690.2246
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- Page 1 1742 Selby Av. St. Paul, MN 55104 6516902246 atmasphere.com MA1 Mk.III amplifier setup and operation instructions Installation: Place the amps in your system. Connect the preamp cable to the appropriate input connector on the rear of the amp. If you use the RCA input connection, make sure a shorting jumper is installed between pins 1 & 3 on the XLR connector else a buzz is possible. Verify that both power switches are OFF (down). Connect AC power to the AC input connector on the rear of the amp. Connect the negative speaker cable to the negative output terminal and the positive speaker cable to the positive output terminal. The amplifier is noninverting from the RCA input or pin 2 of the XLR. Setup: Install the tubes in their sockets. The middle group of five sockets (no cooling holes) take the 6SN7GT driver tube. All others are the 6AS7G output tubes. A total compliment of five driver and fourteen output tubes are required per each chassis. Engage the Main Power switch (amber lamp, left side of chassis) and verify that the amber indicator lights. In about 15 seconds, the filaments of all tubes should be visibly glowing orange. After at least one minute, engage the Standby switch (red lamp, right side of chassis). The amplifier is now fully powered up. DC Offset adjustment/Meter Switch: The middle switch controls the meter. Up is full power for full scale into 8 ohms, Down is 1 watt for full scale. In the Down position, if the meter has a reading with no input signal, adjust the control for no reading. This will be a null or dip in the meter setting. During normal operation, the Low position may only be useful for high efficiency speakers. Use the High position if the meter is pegged to the right In the Low position. Operation: The amplifier is now completely operational. Standby can be used at any time without loss of the warmup character of the amplifier. The MA1 will handle a four ohm speaker rather well. But, as for any tube amplifier, a speaker of 8 ohms is recommended. Speakers of less then 8 ohms or speakers that are four ohms or less in the bass will not demonstrate all the capabilities of any tube amplifier. If you must use a four ohm speaker, be careful to keep the length of the speaker cables as short as possible, and in any event the speaker connections should be as tight as possible. Note that with a tool to tighten the speaker connections on the rear of the amplifier care should be taken not to damage the connectors by overtightening. Speakers of 4 ohms or less can also be used by use of the ZERO product; see http://www.zeroimpedance.com for details. New tubes may exhibit arcovers directly after shipment. If a tube arcs, put the amp in Standby, let it sit for a minute, then tap the tube gently and try the amp again. Often the arcing will clear. If not, replace the tube. Sudden changes in the meter null setting may indicate a damaged tube. If you are unable to adjust the DC Offset this may also be an indication of a bad tube or tubes. If the meter pegs a short is in one of the tubes. Do not allow this condition to persist! The meter will settle out when the offending tube is removed and replaced. Fuses: The fuse by the power cord entry is the Output section B+ and is 5 Amp Slow (2.5A slow for 235V). Check this fuse if the amp lights up but does not play. The middle fuse is the filament fuse and is 5 Amp Slow (2.5A for 235). The last fuse controls the driver circuit and is .5 Amp slow (.25A Slow for 235 Volt). WARNING! To avoid fire hazard, always replace fuses with same type and rating. 2007 AtmaSphere Music Systems Inc. 1742 Selby St. Paul, MN. 55104 651.690.2246 ...
- Page 2 LIMITED WARRANTY ON ATMASPHERE MUSIC SYSTEMS PRODUCTS This warranty on your ATMASPHERE MUSIC SYSTEMS product, which is distributed and warranted by ATMASPHERE MUSIC SYSTEMS, shall remain in effect for three (3) 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. The following are NOT covered by the three year limited warranty: Vacuum tubes are covered for one (1) year, with the following exclusions, as per the rest of the warranty: Damage occurring during shipment (present claims to carrier). Damage resulting from failure or inability to follow proper instructions. Damage resulting from the performance of repairs or modifications by other than ATMASPHERE MUSIC SYSTEMS. WHAT WE WILL PAY FOR: ATMASPHERE MUSIC SYSTEMS will pay for all labor and material expenses for repairs covered by this warranty. HOW TO OBTAIN WARRANTY SERVICE: If your unit requires repairs covered by this warranty, you MUST obtain a return authorization number from ATMASPHERE MUSIC SYSTEMS. You are responsible for transporting the unit to ATMASPHERE MUSIC SYSTEMS, 1742 Selby Av., St. Paul, Minn. 55104. You must pay the initial shipping charges, but ATMASPHERE MUSIC SYSTEMS will pay the return charges, if the repairs are covered by the warranty. All products MUST be shipped in the original carton(s) or in replacement cartons supplied by ATMA SPHERE MUSIC SYSTEMS. Contact ATMASPHERE MUSIC SYSTEMS for replacement cartons and cost. LIABILITY IS LIMITED TO THE REPAIR OR REPLACEMENT, AT OUR OPTION, OF ANY DEFECTIVE PRODUCT AND SHALL IN NO EVENT INCLUDE INCIDENTAL OR CONSEQUENTIAL DAMAGE OF ANY KIND. This warranty is transferable. Warranties of merchantability and fitness for a particular purpose are not implied. This warranty sets forth all expressed warranties made with regard to the above referenced product. We neither assume nor authorize any other liability in connection with the sale or any shipment of products. This warranty gives you specific legal rights and you may also have other rights which vary from state to state. We reserve the right to make changes and improvements in our products without incurring any obligation to similarly alter products previously purchased.
- Page 3 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. NAME_________________________________________________________________________________________________ Address______________________________________________________________________________________________ City__________________________________________________State_______________zipcode_____________________ Country______________________________________________________________________________________________ Name of dealership___________________________________________________________________________________ Model MA-1 Mk. III Date of purchase_______________serial #___________price paid_________________...
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