Owner`s manual

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. Small capacitors may have to be installed between the inputs and ground. See previous section on Phonograph
Hookup.
Distortion:
Check the output tubes (6SN7, upper right in diagram) and the associated 6SN7 in front for defects. If any of the output pins of the main output
XLR connectors other than pin one is at ground potential, distortion may result.
One or both channels out:
There are two fuses located on the right side of the power supply circuit board (as you face the front of the unit), one for each
channel. Replace with the same type slow-blow fuse (.75 Amp for 117 Volt units, .35 Amp for 230 Volt units). If you are not qualified, do not remove the
cover. Hazardous or lethal voltages are present with the cover removed. Refer servicing to qualified service personnel.
Both channels out, intermittent noise or thumping in both channels:
Power supply tube (6080) is loose, defective or not installed.
Low output from one channel:
Check tubes.
DC Offset LED lit up continuously:
Check the 6SN7s (upper right two in diagram) in the channel associated with the LED. If good 6SN7s still lit the LED,
replace the 6080/6AS7A regulator tube. If the LED remains lit, replace the TLO82 opamp ICs on the power supply board by the regulator tube AND the same
ICs inside the head unit by the 6SN7s. They are in sockets and the ICs are availble from Radio Shack or other electronic supply houses. REPLACE the
6080/6AS7A EVERY SIX MONTHS IF THE UNIT IS ON ALL THE TIME. Arc-over failure of the regulator tube will damage all the ICs in the unit.
NEVER, EVER, USE TWEEK® ON TUBE SOCKETS! Tweek® is an organic compound and is capable of forming resistance paths if it breaks down.
If none of these suggestions help, please contact your dealer or ATMA-SPHERE® MUSIC SYSTEMS.
MORE TIPS AND TWEAKS
When ordering from any source, specify tubes for a differential circuit (matched tube sections). The 12AT7s at the input of the phonograph section and the
6SN7 at the input of the high-level section (lower front in diagram) are perhaps the most audible.
Harmonics of the powerline frequency have been shown to be far more problematic for good sound then all other types of powerline problems (RF, spikes,
etc.) put together. Be sure that the conditioner you use can filter line frequency harmonics, particularly the fifth (300 Hz on 60Hz line).
The power cord can have audible effects! A good cable is recommended.
The Sound Anchors equipment stand is the finest we have seen. It is highly recommended. Use it in conjunction with the Ultra Resolution Technologies
vibration-damping platform. Nav-Com Silencers or other anti-vibration pads are also recommended. Tube damping rings are highly recommended.
Most cartridges with more than .2mv seem to work fine. The higher the output the better, tempered with a musical presentation. Some recommended
choices: The Grado Statement and Master Reference, Lyra series (includes the Helicon cartridge), Van Den Hul and Micro Benz. There are of course many
others.