Manley STEELHEAD Version 2 - Manual (Page 13)

Symptom Possible Cause Corrective Action, cont’d
Lights ON, no output Open 6922 filament, either Check for glowing 6922
either channel after warm channel. 6922 unplugged. filaments. Replace if
up delay times out. necessary.
Output MUTE function UnMUTE the preamp.
activated.
Hum heard on unused Input connectors are non- Avoid unused inputs; install
MM or MC inputs. shorting. shorting plugs.
Hum heard on active inputs. Ground link between CHAS-
SYS and CIRCUIT open. Replace jumper if necessary
Turntable / tonearm ground Establish inter-chassis
link to CHASSIS open. connection.
Open cartridge leads. Check lead / head-shell
continuity.
Phono plugs not fully in- Check for proper connection.
serted.
‘Table lines close to hum Keep source lines away from
magnetic field. transformers, motors, etc.
Ground loop between Break ground connection of
STEELHEAD and turntable one or two of the three
or downstream pre-amp/
system elements.
power amplifiers. Experimentation may be necessary.
Faulty shield connection, Roll or swap cables, or
input or output interconnect replace cables.
cables.
No or bad sound heard Check DIN plug wiring Re-wire plug for continuity.
on MC2 input. Left: 1high, 4 low.
Right: 3 high, 5 low,
Shield: 2 earth, chassis.
Remarks on hum pick-up: Please be aware that the STEELHEAD can develop voltage amplification
factors as high as 30,000 times, or 90 dB at the 50-60 Hz power line “hum” frequencies. It is of the utmost
importance that cables handling the tiny signals from the phono cartridges be of high quality, with good
screening and connection properties, if the single-ended signal is to have any chance of being received by the
preamp reasonably free from hum and noise intrusions. This is especially true formoving coil pickups. Please
use the shortest practical interconnects and carefully route these away from all possible electrical or magnetic
hum or interference sources.
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