Manley STEELHEAD Version 1 - Manual (Page 10)

The winking MUTE lamp indicates the beginning of a 30 second warm-up mute delay,
during which time the muting relay is engaged; no output will be heard from the preamp.
DURING OPERATION
Once audio is heard from the STEELHEAD the exploration for the ideal control settings can
begin. However it would be best to allow about 15 minutes of warm-up time for the system to
reach thermal equilibrium.
Again, notice that the MUTE function operates over both FIXED and VARIable outputs,
while the DIM and SUM functions are only available at the VARIable output jacks.
RETURNING TO STANDBY MODE
At the conclusion of your listening session press the STANDBY switch again to cut power
to the preamp. Notice that effort has been made to keep power engagement and cessation noise
generated by the preamp to a minimum. Nevertheless it is wise to remove power mains and signal
feed to your power amps when the preamp is undergoing a power state change.
Additionally, it is best to return the STEELHEAD to the STANDBY mode when not in use
rather then leaving the power on indefinitely. This will enhance tube and system life. The tubes
should last thousands of hours under normal conditions.
REPLACING A TUBE OR ILLUMINATED BADGE LAMP
Yes there are user-servicable parts inside! But, as with other vacuum tube based products,
there is also high voltage present. Therefore caution must be used when covers are removed;
otherwise there could be shock hazard. As with all mains-powered gear make sure the mains power
is off and mains cords are unplugged. Then unplug the power supply from the preamp. If the
preamp has been powered up within the last 15 minutes stop! and let the large internal capacitors
finish discharging. Wait about 5 minutes before opening the preamp once the 16-pin connector is
unplugged.
You will need a #1 Philips screwdriver and a small slot driver.
FUSE-LAMP REPLACEMENT: After removing the cover use the small slot driver to help
pry the badge’s fuse-lamp out of the clip holder. Use one hand only when reaching into the
enclosure or touching any components inside. Keep the other hand away from the preamp,
preferably in your pocket.
TUBE REPLACEMENT: Increased noise level whether gradual or abrupt can generally be
attributed to aging tubes. Gradual noise increase from weakened tube cathode emission is the chief
symptom of an aging tube, which may be accompanied by exaggerated distortion or loss of
headroom. The noise may be a variation in the level of hiss, or the noise may develop a more
granular “large-curd” quality. Should these symptoms appear, unplug the tubes in the offending
channel and replace with new devices of known-good quality. If the front-end 6922 tube is being
replaced in one channel it is wise to replace the same tube in the alternate channel, preferably with
matching manufacturer and date code if possible.