Butler TUBE DRIVER BLUE 2250 Technical manual

A U D I O, I N C
WWW.BUTLERAUDIO.COM
OWNER'S INFORMATION FOR
MODEL 2250
MODULAR DIRECT-COUPLED
VACUUM TUBE DRIVEN
TWO CHANNEL POWER AMPLIFIER
UTILIZING
b
T H E R M I O N I C
VACUUM TUBE TECHNOLOGY
Concept & Design: B K Butler
Patented in the USA
Worldwide patents pending
"Tube Driver", "Tube Driver Blue", "Thermionic" and Blue Tube illumination appearance / method are
trademarks of or patented by
BK Butler

Contents
Congratulations………..…………………………………… 1
Product Description
Power Output
Protection………………………………………………..…… 2
Use and Operation
Front Panel Power Switch
Rear Panel Remote Jack………………………...…….. 3
Inputs
Speaker Output Binding Posts
Speaker Phasing
Remote Operation….…………………….…….....……… 4
Specifications……….…………………………………..…… 5
Cable Quality
The Marvelous Vacuum Tube………..………………. 6
Tube Reliability……………………………………………….. 7
Warranty & Repair Policy….……………………………8

Congratulations
Please accept our sincere thanks and congratulations for making
your musical choice Butler Audio. This newUSA-Patented
technology from BK Butler promises to become a classic design,
just as his former efforts have in the professional music and auto
sound industry.
After more than 25 years of tube audio experience in the
Professional Music Industry with some of the world's greatest
musical talents, BK Butler has now created an entirely new class of
home audio and theater amplifier products. With careful emphasis
on the achievement of practical "all tube" response characteristics,
Butler Audio's Tube DriverbBLUE technology satisfies even the
most critical vacuum tube audiophiles.
The Past is the Futureu
For the first time in the history of tube amplifier design, the original
"Edison Effect," or theessence of pure Thermionic vacuum tube
emissions have been fully utilized to yield very lowdistortion and
produce "all tube" type musical response characteristics in a multi-
channel home amplifier. With painstaking efforts and great
attention to detail, BK Butler has balanced the sonic response, load
and transfer characteristics of individually selected twin triode
vacuum tubes to operate under optimum conditions in this open-
ended ZERO global negative feedback circuit topology.
Previous hybrid designs employing vacuum tubes generally utilized
tubes only in impedance-isolated preamp or driver stages.
However, Butler places the triodes exactly where they should be:
DC -Coupled through the output power devices to the speakers.
Therefore, the tubes are positioned to naturally and actively
respond to the speaker load. This also completely eliminates one of
the most inefficient and non-musical components in a typical tube
power amplifier: the Output Transformer. Without hundreds of
feet of phase-shifting, musicality-robbing wire and many pounds of
induction-generating core iron to overcome, Butler's newly
patented current-multiplying DC coupling circuitry allows the output
driver tubes to directly operate into the fixed ratio-reduced
speaker output load. This novel design results in the production of
authentic power vacuum tube characteristics hundreds of times
greater than normal capabilities of the driver tubes.
Comparable in concept to precision racecar active power steering,
Butler allows the tubes to "power steer" the audio output signal
directly into your speakers. The result: A superlative marriage of
tube and solid-state technology without the limitations of either.
Literally, you get the reliable, efficient power capability of solid-state
with all the greatly extended dynamics, warmth and musicality of the
highest quality vacuum tube design available today.

Product Description:
Butler Audio Model 2250 is a vacuum tube-driven 2-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.
A separate 5-way speaker output binding post is provided for Mono
operation An internal AC Relay is included internally 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 therear 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 250 Watts, RMS per channel into 8 Ohms, both channels
operating simultaneously. Each channel is also capable of
producing 400 Watts, RMS per channel into 4 Ohms. An
appropriate source of 120VAC nominal input line voltage with a
minimum current supply of 12A is required. 230-240 VAC models
require approx. 50% of the current rating of 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 witha 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, one power
modules will probably click "on" earlier than the other.
5) Main DC Power (+/-75V) 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.

6) DC Offset Voltage at Speaker Output: Continuous monitoring
circuit immediately opens the speaker relay upon the
detection of any excessive DC voltagelevel.
7) Short circuit protection: In addition to the Main DC Power
Fuses, mentioned in #4 above, this continuously active circuit
becomes active to the speaker output below a load of approx.
2 ohms. It will prevent a catastrophic over-current condition
for the output devices in the case of a direct short circuit
between the + and -output speaker binding posts.
8) Over Temp Circuit Breaker: Opens the speaker relay if the
heatsink temperature exceeds 115 deg. C. If this occurs, the
amp should automatically begin operate again after the
temperature has decreased sufficiently.
NOTE: BE CERTAIN THAT AIR FLOW IS COMPLETELY UNRESTRICTED ABOVE
AND BELOW THE AMPLIFIER. IF RACKMOUNTED, LEAVE AT LEAST A
STANDARD SINGLE SPACE BETWEEN THE NEXT PIECE OF EQUIPMENT (TOP
AND BOTTOM) OR PROVIDE FORCED AIR COOLING. THIS AMP IS DESIGNED
FOR USE ONLY AT ROOM TEMPERATURE WITH ADEQUATE VENTILATION AND
CIRCULATION.
IMPORTANT: COOL OPERATION = LONGEST LIFE AND RELIABILITY!
DO NOT OPERATE WITHIN A COMPLETELY CLOSED CABINET OR ENCLOSURE!
LET YOUR AMP BREATHE!
Use and Operation:
Important: Do not apply power until you have read and understand this section!
Connect or disconnect cables only with amplifier OFF.
Note: Your new Butler Audio amp is designed to operate in stereo with ONE separate
speaker system connected per channel.Connect "Speaker Outputs" to speakers only!
DO NOT SHORT ANY SPEAKER OUTPUT POST TERMINAL TO ANY OTHER SPEAKER
OUTPUT POST TERMINAL. CONNECT EACH SEPARATE SPEAKER LOAD ONLY
BETWEEN THE SPEAKER POSTS OF PAIR CHANNEL. WHEN USING MONO MODE
(BRIDGED), BE SURE TO SELECT THE “MONO” SETTING (DOWN POSITION) OF THE
STEREO/MONO SWITCH.
Front Panel Power Switch:
Suppliesmain AC power to the amplifier. The ON position is up and
will be indicated by the blue LED indicator and the glow of the tubes
through the front panel louvers.
Rear Panel Remote Jack:
This 3.5mm standard mini phone jack is connected to a heavy duty
AC relay that parallels the operation of the Front Panel Power
Switch. Therefore if remote operation is desired, leave the switch
in the OFF (down) position. Whenever an 8 -13V DC voltage is
supplied to the jack (either polarity) the amp will be turned ON just
as if the front power switch were used. It will not harm the amplifier
if the front panel power switch is turned ON with the relay activated,
but this will disable the remote function until it is switched OFF
again.