TROUBLESHOOTING
TIPS
Bottom front panel LED won't light up: Check the rear panel AC connector and verify that the power cord
is plugged in. If so, the internal 1.5Amp SLOW BLOW (.75A if 235 Volts) fuse may be blown.
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 common with
modern straight-tracking arms. Buzz can also occur if the input of the amplifier is not properly balanced.
Distortion: Check the output tube (6SN7) and the associated 12AU7 for defects.
Both channels dead, unit lights up: There is a fuse located on the rear right side edge of the circuit board
(as you face the front of the unit). 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.
LED lit up continuously: Check the 6SN7 in the channel associated with the LED. If the LED remains lit,
replace the TLO82 opamp ICs beside the associated 6SN7. They are in sockets and the ICs are
available from Radio Shack or other electronic supply houses.
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
You can reduce the noise level beyond the specification by using low noise tubes. When ordering from
any source, specify tubes for a differential circuit (matched tube sections). We have found that the 12AT7
at the input of the phonograph section, and the 12AU7 at the input of the high-level section are perhaps
the most audible.
We recommend line conditioning. The fifth harmonic of the powerline frequency has 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).
We have found that 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.
A cartridge with .3mv or more is recommended.