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Product Description:
Butler Audio Models 5150 is a vacuum tube-driven 5-channel power
amplifier. Each channel Power Module is completely independent
and includes separate RCA input and 5-way speaker output binding
posts, vacuum tube, rectifier & filter capacitors, electronic
components, protection and output power devices, etc. Butler
Audio Model 3150 is identical to all descriptions within this booklet
except that Power Modules 2 and 4 have been removed for a total
of 3 channels. An internal AC Relay is provided for remote operation
from a pre-amp capable of providing a voltage of 8 - 13V DC (either
polarity) via the 3.5mm input jack on the rear panel.
Note: Leave the front panel AC Power switch in the "OFF" (down) position for
remote operation.
Power Output:
Each channel is powered by a separate secondary winding from the
massive 2KW-rated power toroid transformer. This yields a power
rating of 150 Watts, RMS per channel into 8 Ohms, all channels
operating simultaneously. Each channel is also capable of producing
225 Watts, RMS per channel into 4 Ohms. An appropriate source
of 115 -120VAC nominal input line voltage with a minimum current
supply of 15A for the 5150 or 12A for the 3150 is required.
230VAC models require approx. 50% of the current rating of 115-
120V models.
Protection:
Listed below are the various types of internal protection provided
for unexpected conditions:
1) AC input fuse for protection against any major system power
fault. Do not replace with a fuse of higher current rating!
2) Protection against AC input line transient voltage spikes and
surges.
3) Slow vacuum tube filament warm-up: Provides safe, fully
regulated, slow turn-on 6.3VDC for the tube heater filaments.
This technique promotes longest tube life.
4) Turn-on and warm-up transient delay: This circuit will not allow
the speaker relay to close (connect power module output to
speaker posts) for a delay of approximately 20 - 30 sec. after
turn-on. This provides for safe vacuum tube warm-up and
output stabilization.
Note: Due to normal component tolerance differences, some power
modules will click "on" earlier than others.
5) Main DC Power (+/- 65V) Fuses: A red LED will be visible from
the front panel adjacent to the tube of the affected channel if a
fault condition causes a fuse to open.