Atma-Sphere M-60 MkIII Owner's Manual

1742 Selby Av.
St. Paul, MN 55104

651-690-2246
atma-sphere.com

Atma-Sphere M-60 Mk. III amplifier setup and operation instructions

Installation: Place the amps in your system. Allow for adequate cooling- do not set the
amp on a carpet, and if in a cabinet you may have to set up a cooling fan as well. Connect
the preamp cable to the appropriate input connector on the front of the amp. If you use
the RCA input connector, make sure a shorting jumper is installed between pins 1 & 3 on
the XLR connector else a buzz may result. Verify that both power switches are OFF and
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.

Setup: Install the tubes in their sockets. The middle four sockets take the 6SN7GT driver
tube. All other sockets take the 6AS7G output tube. A total compliment of four driver and
eight output tubes are required per each chassis. Engage the main power switch (left edge
of chassis, amber lamp) and verify that the amber indicator lights. In about 15 seconds,
the filaments of all tubes should be visibly glowing orange. Wait at least one minute,
then engage the standby switch (right side of chassis) and verify that the red indicator
lights. The amplifier is now fully powered up.

Meter Range/Meter Switch: The meter is operational all the time. The small toggle switch
to the right of the input connectors controls its range. Up is is the high range- full
output from the amplifier will result in full scale deflection. Down is 1 watt for full
scale, and is useful on high efficiency speakers and the DC Offset Null adjustment. The
meter is calibrated for 8 ohms.

DC Offset Null adjustment: Place Meter Switch in the down position. Examine the
reading on the VU meter. If it is NOT -20db (zero on the bottom scale) use the DC Null
control to bring the meter to its lowest reading. Note that if you overshoot the setting
the meter will rise again- set for the lowest reading. Bias is automatic. Note: It may not
be possible to null the DC Offset if there are defective tubes in the amplifier.

Operation: The amplifier is now completely operational. It can be set in standby or fully
On at will. Note: Some bluish florescence of the output tubes is normal.

At the time of this writing, the M-60 is the most neutral and musical 60-watt amplifier
available. It is quite transparent. Be prepared to hear things you have not heard before­both good and bad. Many preconceived notions may have to go in order for you to get the
most out of the M-60. We recommend that as you make improvements in your system, make only
one change at a time in order to understand its significance. As always, feel free to
contact Atma-Sphere for advice.

Fuses: The first fuse by the power cord entry is the Output section B+ and is 3 Amp Slow
(1.5A slow for 235V). The second fuse is for the output filaments and is 3 Amp Slow (1.5A
for 235). The last fuse controls the driver circuit and is 0.5 Amp slow (0.25A Slow for
235 Volt). WARNING! To avoid fire hazard, always replace fuses with same type and rating.

© 2005 Atma-Sphere Music Systems Inc. 1742 Selby Av., St. Paul, MN. 55104 651.690.2246

1742 Selby Av.
St. Paul, MN 55104

651-690-2246
atma-sphere.com

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 three (3) years from
the date of consumer purchase, provided the enclosed registration form is completed and
returned to ATMA-SPHERE 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
ATMA-SPHERE MUSIC SYSTEMS.

WHAT WE WILL PAY FOR:

ATMA-SPHERE 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 ATMA-SPHERE MUSIC SYSTEMS. You are responsible for transporting
the unit to ATMA-SPHERE MUSIC SYSTEMS, 1742 Selby Av., St. Paul, MN 55104. You must pay
the initial shipping charges, but ATMA-SPHERE 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. Implied warranties of merchantability and fitness for a
particular purpose are limited in duration to the length of this warranty. 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.