Mapletree Black Buff User manual

Black Buff Amplifier
Users' Manual
Rev Oct. 22/16
Mapletree Audio esign
Al Freundorfer
www.mapletreeaudio.com
[e-mail]
© Copyright Al Freundorfer 2016
0

Introduction
The Black Buff is designed as a stand-alone tube-output-buffer for C players, AC or any line level
device. The result is an improved tonal quality, relaxed open musical detail and imaging, reduced
listener's fatigue and enhanced 3 effect of better recordings.
The Mapletree Audio esign Black Buff Amplifier represents a high performance development of an
octal-based buffer amplifier that uses the 6SN7/5692 or 12SN7 and is based on the cathode follower
from the Mapletree Audio Line 2 and Ultra 4 pre-amplifiers. Premium components include metal film
resistors and polypropylene film capacitors.
Many people would like to have the tube sound in their home theater without buying and building an
expensive all tube system. This can be solved by adding three Black Buffs to the outputs of a
V /Home Theater player to bring its performance up to a tube level quality. Placing one Black Buff
on the front channel, one on the rear channels and a final unit on the center channel and sub output
(three Black Buffs total), turns your V /Home Theater player into a respectable sounding 6 channel
tube output with excellent sound.
Input/Output Connections
There are a single pair of RCA input and output connections. The RCA jacks allow connection to a
line-level stereo source while maintaining the connection to the regular amplification system. The input
impedance is 1 MΩ which is compatible with all source output circuits. The RCA output jacks are also
at the rear of the Black Buff and can handle loads as low as 5K ohms.
The standard IEC line cord is attached to the receptacle on the rear panel of the Black Buff power
supply. It is compatible with a 120 AC volts. A 0.25A/120 V fuse provides primary protection for the
power supply. It is located on the back of the power supply unit. Under normal conditions, it should not
be necessary to replace the fuse. If power fails to come on, you can check the fuse and replace with a
spare if necessary. If the fuse blows a second time, you should not try to operate the unit. Contact
Mapletree Audio esign for information regarding servicing. The power switches are located on the
front panel and the LE pilot light indicates the power on.
1

Black Buff
2
Fuse
Holder
120 VAC Power
Input
Power Indicator LED
Power Switch
Tu e sound control
Min. Tu e sound:
Full Counter-
Clockwise
Max. Tu e sound:
Full Clockwise
When turning the knob
allow the bias to settle,
approximately 3
seconds, before critical
listening. Normally
after turning the knob
the output would sound
quieter with volume
slowly increasing and
improving in clarity.
Audio
Input
Audio
Output Heater Voltage Switch
(6.3 VDC down and 12.6VDC up)

Controls
The Tube sound level controls the amount of tube sound is added to the audio from input to output
when the selector switch is set to Black buff mode. When turning the knob allow the bias to settle,
approximately 3 seconds, before critical listening. Normally after turning the knob the output would
sound quieter with volume slowly increasing and improving in clarity.
Tubes
A tube burn-in period of several hours may be needed to achieve the best sonic performance. Tube life
should be thousands of hours. Aging tubes may result in a reduced gain in one or both channels or an
increase in noise levels. Infrequently, a heater may burn out which is indicated by total loss of sound.
The Black Buff is supplied with 1 – 6SN7 or 12SN7 tube. Replacement tubes can be obtained from
several suppliers in the U. S. and Canada. 6SN7 types are currently manufactured and are also available
as new old stock (NOS). Some listeners enjoy trying different brands and variants of tubes. The greatest
sonic variation will occur with different driver tubes.
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123

Warranty
Tubes are warranted for 90 days exclusive of shipping cost.
Additional Notes
This manual is an aid to the user for the operation of the Black Buff. etails of the amplifier and power supply circuits are
subject to change without notice so as to achieve the best possible performance. The schematic is only representative of the
actual amplifier and component manufactures, model and values may vary.
4
Back
6SN7 or 5692
Front

MAD Black Buff pecifications
Frequency response at 0.2 Vrms output into 4.5k, 10k and 25k Ohms load:
10 100 1000 10000 100000
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
Series1
Series1
Series1
Frequency [Hz]
Relative Gain [dB]
1Vrms output at 1 kHz: 10K Ohm load predominately 2nd order distortion.
Output impedance at 1 kHz: 454 Ω
Input impedance: 20 kΩ
Hum and noise at output: less than 0.1m Vrms
Phase: non-inverting
Power consumption: 4 W, 120 VAC (230 and 240 VAC) 50-60 Hz
5
Vout=1.0 Vrms
10 100 1000 10000 100000
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
4.5k Ohm Load
Frequency [Hz]
Relative Gain [dB]
4.5K Ohm Load
10 K Ohm Load
25 K Ohm Load

MAD Black Buff Headphone Amplifier
Ver ion: 4
© Copyright Al P Freundorfer 2016
Rev. Oct. 2016
6