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.
